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Open AccessEditorial

Preface: The European Navigation Conference 2024 (ENC 2024)

by Terry Moore

Eng. Proc. 2025, 88(1), 80; https://doi.org/10.3390/engproc2025088080 - 14 Jan 2026

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Abstract

The European Navigation Conference 2024 (ENC 2024) took place at the European Space Research and Technology Centre (ESTEC) of the European Space Agency (ESA) in Noordwijk, the Netherlands, from 22 to 24 May 2024 [...] Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2268 KB

Open AccessProceeding Paper

Evaluation of H-ARAIM Reference Algorithm Performance Using Flight Data

by Natali Caccioppoli, David Duchet and Gerhard Berz

Eng. Proc. 2025, 88(1), 1; https://doi.org/10.3390/engproc2025088001 - 14 Mar 2025

Viewed by 1935

Abstract

Currently, relevant efforts are being dedicated to the implementation of Advanced Receiver Autonomous Integrity Monitoring (ARAIM) in future aviation receiver standards. These contributions focus on the specific aspects of algorithm processing and performance using simulated or real static user grid data. However, significant [...] Read more.

Currently, relevant efforts are being dedicated to the implementation of Advanced Receiver Autonomous Integrity Monitoring (ARAIM) in future aviation receiver standards. These contributions focus on the specific aspects of algorithm processing and performance using simulated or real static user grid data. However, significant differences in the quality of measurements made by ground receivers compared to an avionics receiver may arise due to operational constraints such as space weather (troposphere and/or ionosphere), multipath, signal outages, and cycle slips. The objective of our work is to evaluate the Horizontal-ARAIM (H-ARAIM) reference algorithm sensitivity in an operational scenario using GPS and GALILEO dual-frequency flight data. Navigation performances are analyzed for typical arrival and approach maneuvers with respect to positioning accuracy and integrity for Required Navigation Performance (RNP) specifications, along with the evaluation of algorithm computational load when subjected to the dynamics of the aircraft. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4626 KB

Open AccessProceeding Paper

Performance Analysis for the Galileo High-Accuracy Service and Related Work in the DLR Galileo Competence Center

by Marios Smyrnaios, Wolfgang Dilg, Katharina Lutz, Bernhard Röttgers and Johann Furthner

Eng. Proc. 2025, 88(1), 2; https://doi.org/10.3390/engproc2025088002 - 14 Mar 2025

Cited by 1 | Viewed by 3278

Abstract

A system for monitoring and analyzing GNSS performance is being developed at DLR’s Galileo Competence Centre. Various parameters are monitored in order to characterize the performance of the four global satellite navigation systems. The focus of this contribution is on the extension of [...] Read more.

A system for monitoring and analyzing GNSS performance is being developed at DLR’s Galileo Competence Centre. Various parameters are monitored in order to characterize the performance of the four global satellite navigation systems. The focus of this contribution is on the extension of our system with monitoring and analysis capabilities for the Galileo HAS and specifically for the Internet Data Distribution component of the service. An initial analysis of the content of the HAS messages and the positioning performance of the service at example IGS station locations is discussed. Our analysis shows the continuous availability of the internet distribution component of the service and a horizontal positioning performance of the order of 20 cm or better for 95% of the epochs of the selected time periods and for the selected station locations. In addition to HAS, we also examined an additional set of performance parameters, which show similar performance levels between the Galileo, GPS and BeiDou systems. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 7682 KB

Open AccessProceeding Paper

Maximum Tolerable Multipath for Successful Meta-Signal Sub-Carrier Ambiguity Fixing

by Mohamed Bochkati, Ece Kayacilar, Muhammad S. Hameed, Markel Arizabaleta-Diez and Thomas Pany

Eng. Proc. 2025, 88(1), 3; https://doi.org/10.3390/engproc2025088003 - 14 Mar 2025

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Abstract

The prospect of GNSS meta-signal tracking promises the synergy of both code reliability and the high precision of sub-carrier observations. The latter has the advantage, in comparison to carrier-phase observations, of having wavelengths in the order of a few meters instead of cm-level. [...] Read more.

The prospect of GNSS meta-signal tracking promises the synergy of both code reliability and the high precision of sub-carrier observations. The latter has the advantage, in comparison to carrier-phase observations, of having wavelengths in the order of a few meters instead of cm-level. This realizes the possibility of resolving sub-carrier-phase ambiguities without the need for a reference station providing positioning solutions with a sub-meter level of accuracy. In the frame of the HANDS-CD project led by IGASPIN GmbH, a synthetic meta-signal observation formed from Galileo E5a and E5b signals using the widelaning concept will be demonstrated in this contribution. This analysis is performed based on a simulated kinematic trajectory. The synthetic meta-signal observations are fed into an extended Kalman filter-based positioning engine called the meta-signal positioning engine (M-SiPE-tool), which applies the least-squares ambiguity decorrelation adjustment (LAMBDA) ambiguity fixing method to resolve the sub-carrier ambiguities. To assess the robustness of the positioning filter against signal impairments, the observations of many Galileo satellites are synthetically contaminated by multipath reflection with different amplitudes. The outcome of the positioning engine exhibits successful sub-carrier ambiguity fixing and provides a sub-decimeter positioning accuracy for a code multipath amplitude of less than 30 m, or for a sub-carrier multipath amplitude of less than 0.5 m. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 3772 KB

Open AccessProceeding Paper

LDACS PNT Architecture Integrating Asymmetric Two-Way Timing Filters for Enhanced and Reliable Positioning

by Gianluca Zampieri, Gary McGraw, Brandon Weaver and Michael Meurer

Eng. Proc. 2025, 88(1), 4; https://doi.org/10.3390/engproc2025088004 - 17 Mar 2025

Cited by 2 | Viewed by 1258

Abstract

This research investigates the positioning performance of the L-band Digital Aeronautical Communications System (LDACS) and presents a system architecture based on carrier-smoothed ground-to-air pseudoranges (PRs), along with clock corrections derived from asymmetric two-way time and frequency transfer (A-TWTFT) filters. The objective is to [...] Read more.

This research investigates the positioning performance of the L-band Digital Aeronautical Communications System (LDACS) and presents a system architecture based on carrier-smoothed ground-to-air pseudoranges (PRs), along with clock corrections derived from asymmetric two-way time and frequency transfer (A-TWTFT) filters. The objective is to achieve required positioning accuracy and integrity for aviation operations, addressing the complexities associated with utilizing a terrestrial communications system for complementary positioning, navigation, and timing (CPNT). Through error covariance analysis, this study assesses the steady-state value, convergence time, and bounding performances of the filters. The positioning performance highlights the benefits provided by the proposed architecture. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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8 pages, 2885 KB

Open AccessProceeding Paper

Resilient Time Dissemination Fusion Framework for UAVs for Smart Cities

by Sorin Andrei Negru, Triyan Pal Arora, Ivan Petrunin, Weisi Guo, Antonios Tsourdos, David Sweet and George Dunlop

Eng. Proc. 2025, 88(1), 5; https://doi.org/10.3390/engproc2025088005 - 17 Mar 2025

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Abstract

Future smart cities will consist of a heterogeneous environment, including UGVs (Unmanned Ground Vehicles) and UAVs (Unmanned Aerial Vehicles), used for different applications such as last mile delivery. Considering the vulnerabilities of GNSS (Global Navigation System Satellite) in urban environments, a resilient PNT [...] Read more.

Future smart cities will consist of a heterogeneous environment, including UGVs (Unmanned Ground Vehicles) and UAVs (Unmanned Aerial Vehicles), used for different applications such as last mile delivery. Considering the vulnerabilities of GNSS (Global Navigation System Satellite) in urban environments, a resilient PNT (Position, Navigation, Timing) solution is needed. A key research question within the PNT community is the capability to deliver a robust and resilient time solution to multiple devices simultaneously. The paper is proposing an innovative time dissemination framework, based on IQuila’s SDN (Software Defined Network) and quantum random key encryption from Quantum Dice to multiple users. The time signal is disseminated using a wireless IEEE 802.11ax, through a wireless AP (Access point) which is received by each user, where a KF (Kalman Filter) is used to enhance the timing resilience of each client into the framework. Each user is equipped with a Jetson Nano board as CC (Companion Computer), a GNSS receiver, an IEEE 802.11ax wireless card, an embedded RTC (Real Time clock) system, and a Pixhawk 2.1 as FCU (Flight Control Unit). The paper is presenting the performance of the fusion framework using the MUEAVI (Multi-user Environment for Autonomous Vehicle Innovation) Cranfield’s University facility. Results showed that an alternative timing source can securely be delivered fulfilling last mile delivery requirements for aerial platforms achieving sub millisecond offset. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 1170 KB

Open AccessProceeding Paper

The ConTAD Project: Detection of Multi-Container Loss for Safety of Navigation

by Moritz Oberjatzas, Christian Denker, Hanns-Christian Wüstner and Moritz Schmidt

Eng. Proc. 2025, 88(1), 6; https://doi.org/10.3390/engproc2025088006 - 17 Mar 2025

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Abstract

In recent years, there has been a significant increase in the number of shipping containers lost at sea. Such incidents result in environmental pollution and economic costs. Given that the underlying causes of container loss are not yet fully understood, it is reasonable [...] Read more.

In recent years, there has been a significant increase in the number of shipping containers lost at sea. Such incidents result in environmental pollution and economic costs. Given that the underlying causes of container loss are not yet fully understood, it is reasonable to assume that further incidents will occur in the future. The research in the ConTAD project aims to automatically detect multi-container loss with the use of advanced container tracking technology. This paper presents the concept behind the targeted container tracking device, which will be designed to reduce the environmental and economic impact of container loss in the future. A container loss accident phase model is proposed to visualize the impact of the new container tracking technology. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1305 KB

Open AccessProceeding Paper

Low-Cost SDR for GNSS Interference Mitigation Using Spatial Diversity Techniques

by Lucía Pallarés-Rodríguez, David Gómez-Casco, Noori Bni-Lam, Gonzalo Seco-Granados, José A. López-Salcedo and Paolo Crosta

Eng. Proc. 2025, 88(1), 7; https://doi.org/10.3390/engproc2025088007 - 17 Mar 2025

Cited by 2 | Viewed by 2738

Abstract

This paper addresses the feasibility of implementing spatial diversity techniques to mitigate interference signals using low-cost GNSS receivers. Global Navigation Satellite Systems (GNSSs) remain at the core of navigation technologies and obtaining precise and robust positioning solutions in harsh scenarios becomes essential for [...] Read more.

This paper addresses the feasibility of implementing spatial diversity techniques to mitigate interference signals using low-cost GNSS receivers. Global Navigation Satellite Systems (GNSSs) remain at the core of navigation technologies and obtaining precise and robust positioning solutions in harsh scenarios becomes essential for the proper functioning of modern applications. Furthermore, this challenge is even more complex when mass-market receivers are addressed, since the previous requirements must be achieved while maintaining low-cost architectures. A promising solution is to use beamforming techniques, which exploit the spatial domain to achieve enhanced reliability and robustness. In this paper, the potential of beamforming in mass-market receivers is analyzed by implementing two interference mitigation techniques and using a five-channel low-cost software defined radio (SDR), KrakenSDR. The results show that the algorithms implemented are able to mitigate strong interference signals, allowing the GNSS receiver to compute an accurate positioning solution. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 3939 KB

Open AccessProceeding Paper

Interference Monitoring from Low Earth Orbit: The OPS-SAT Experiment

by Francesco Menzione, Ottavio M. Picchi, Tommaso Senni, Vladimir Zelenevskiy, Luca Cucchi, Andrea Piccolo and Joaquim Fortuny-Guasch

Eng. Proc. 2025, 88(1), 8; https://doi.org/10.3390/engproc2025088008 - 17 Mar 2025

Cited by 4 | Viewed by 3144

Abstract

In the context of the Jammertest 2023, a collaborative experiment was carried out by the European Commission Joint Research Centre (JRC), the European Space Operations Centre of ESA (ESOC), the Norwegian Communication Authority, and the Norwegian Defense Research Establishment (FFI) to explore potential [...] Read more.

In the context of the Jammertest 2023, a collaborative experiment was carried out by the European Commission Joint Research Centre (JRC), the European Space Operations Centre of ESA (ESOC), the Norwegian Communication Authority, and the Norwegian Defense Research Establishment (FFI) to explore potential RF interference monitoring in the navigation GNSS band from LEO. The experiment utilizes the ESA OPS-SAT satellite and the possibility of transmitting a custom jamming signal pattern during the Jammertest event. The objective is to validate the feasibility of detecting and locating ground-generated jamming signals using SDR technology on-board LEO. The insight into the signal structure and location provides a unique chance to assess the performance and limitations of this approach in a real-world scenario. This paper presents the processing of raw RF data collected during the in-flight experiment, including the generation of frequency difference of arrival (FDOA) observables and emitter geolocation. Despite the constraints posed by onboard resources and mission limitations, this work offers a persuasive proof of concept and suggests new guidelines for implementing this technology on future LEO missions. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 5167 KB

Open AccessProceeding Paper

GNSS Constellations Monitoring Using a Phased Array Antenna System

by Lionel Tombakdjian, Noori BniLam, Fabien Ferrero and Paolo Crosta

Eng. Proc. 2025, 88(1), 9; https://doi.org/10.3390/engproc2025088009 - 18 Mar 2025

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Abstract

This study presents a novel approach to enhance GNSS (Global Navigation Satellite System) signal reception using an eight-port beamformer tailored for satellite navigation applications. The beamformer architecture integrates key stages including filtering, amplification, phase shifting, and signal combination to optimize signal reception. For [...] Read more.

This study presents a novel approach to enhance GNSS (Global Navigation Satellite System) signal reception using an eight-port beamformer tailored for satellite navigation applications. The beamformer architecture integrates key stages including filtering, amplification, phase shifting, and signal combination to optimize signal reception. For demonstration, a GNSS signal generator simulates a four-element phased array antenna, emitting GPS L1 constellation signals across four outputs connected to the beamformer ports. By manipulating phase settings on each port, the beamformer enables beam steering, showcasing improved signal detection. The results highlight the efficacy of the custom beamformer in enhancing GNSS signal reception and suggest promising implications for satellite signal tracking and navigation. This research contributes valuable insights into advanced antenna design and signal processing strategies for optimizing GNSS performance. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 8349 KB

Open AccessProceeding Paper

Hybrid Cycle Slip Detection Method for Smartphone Global Navigation Satellite System

by Naman Agarwal and Kyle O’Keefe

Eng. Proc. 2025, 88(1), 10; https://doi.org/10.3390/engproc2025088010 - 18 Mar 2025

Cited by 3 | Viewed by 1466

Abstract

The main roadblock to precise Smartphone GNSS positioning is erroneous carrier phase data which is highly prone to cycle slips (CSs). There is a dearth of research on cycle slip detection and repair (CSDR) methods for Smartphone GNSS. Existing literature on CSDR methods [...] Read more.

The main roadblock to precise Smartphone GNSS positioning is erroneous carrier phase data which is highly prone to cycle slips (CSs). There is a dearth of research on cycle slip detection and repair (CSDR) methods for Smartphone GNSS. Existing literature on CSDR methods is based on phase data captured by professional-grade receivers. These methods can be broadly categorized into two groups: (1) Geometry-Free CSDR (GF-CSDR) and (2) Geometry-Based CSDR (GB-CSDR). GF-CSDR methods rely on individual satellite measurements, whereas the GB-CSDR technique considers the whole satellite–receiver geometry. This paper proposes a real-time single-frequency CSDR method combining both GF and GB-CSDR. Experimental results are presented for a static and a kinematic smartphone dataset. It is shown that although reliable CS detection is possible for Smartphone GNSS, CS repair reliability is limited due to the carrier phase precision quality. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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7 pages, 2872 KB

Open AccessProceeding Paper

Drone-Based Radar Terrain-Referenced Navigation Using a Low-Cost Automotive-Class FMCW Radar to Enable GNSS-Denied Navigation

by John Markow and Aled Catherall

Eng. Proc. 2025, 88(1), 11; https://doi.org/10.3390/engproc2025088011 - 19 Mar 2025

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Abstract

Drones are increasingly being used for a variety of applications, but their use can be hampered when Global Navigation Satellite System (GNSS) signals are unavailable. This paper presents Terrain-Referenced Navigation (TRN) from a class 1 drone using a low-cost, automotive-class mm-wave radar to [...] Read more.

Drones are increasingly being used for a variety of applications, but their use can be hampered when Global Navigation Satellite System (GNSS) signals are unavailable. This paper presents Terrain-Referenced Navigation (TRN) from a class 1 drone using a low-cost, automotive-class mm-wave radar to enable accurate navigation in GNSS-denied environments. The radar-derived elevation profile of the ground beneath the drone as it flies is compared to a light detection and ranging (lidar)-based digital terrain map, and using a particle filter, the drone’s position is estimated. Results show that mm-wave radar TRN can provide an accurate navigation capability in the absence of GNSS and offers several advantages over other alternative navigation technologies. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2900 KB

Open AccessProceeding Paper

Sensitivity Analysis of Galileo OSNMA Cross-Authentication Sequences

by Aleix Galan, Cillian O’Driscoll, Ignacio Fernandez-Hernandez and Sofie Pollin

Eng. Proc. 2025, 88(1), 12; https://doi.org/10.3390/engproc2025088012 - 20 Mar 2025

Cited by 3 | Viewed by 1931

Abstract

The Galileo Open Service Navigation Message Authentication (OSNMA) service has been transmitting stably in recent years and is expected to be declared operational in the next months. While the protocol is very flexible, most of the parameters, such as key and tag sizes [...] Read more.

The Galileo Open Service Navigation Message Authentication (OSNMA) service has been transmitting stably in recent years and is expected to be declared operational in the next months. While the protocol is very flexible, most of the parameters, such as key and tag sizes and cryptographic functions, have been already fixed in view of the operational declaration. However, some degree of flexibility remains in the tag and cross-authentication sequence. The cross-authentication sequence defines the satellites “cross-authenticated” by an authenticating Galileo satellite and is one of the main properties of the OSNMA protocol. It facilitates the authentication of nearby Galileo satellites for higher redundancy against losses, authenticating data from satellites not connected to the ground and therefore not transmitting OSNMA, and authenticating GPS or other data in the future. It has a significant impact on OSNMA performance: if the sequence is too long, many cross-authenticated satellites will not be seen by the users, limiting the optimal use of the OSNMA bandwidth, and with a major impact on TBA (Time Between Authentications) and Time To First Authenticated Fix (TTFAF). If the sequence is too short, several non-connected but visible satellites may remain unauthenticated, also degrading performance. This paper presents an analysis with real SIS data from different cross-authentication sequences transmitted by Galileo in recent months, involving different tag distribution and a number of cross-authenticated satellites including open-sky static, dynamic, and urban environments. This work shows the degradation with sub-optimal cross-authentication sequences and identifies current bottlenecks, proposing some recommendations for future sequences. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 7211 KB

Open AccessProceeding Paper

Monitoring and Data Distribution of the Galileo High-Accuracy Service System and User Performance

by Paolo Zoccarato, Francesco Menzione, Ciro Gioia, Joaquim Fortuny-Guasch and Matteo Paonni

Eng. Proc. 2025, 88(1), 13; https://doi.org/10.3390/engproc2025088013 - 20 Mar 2025

Cited by 1 | Viewed by 3140

Abstract

Global Navigation Satellite Systems (GNSSs) provide free services such as the Galileo High-Accuracy Service (HAS) to enhance navigation precision. The Joint Research Centre (JRC) developed a monitoring system for HAS corrections from Galileo signals and the internet, comparing them with Multi-GNSS Experiment (MGEX) [...] Read more.

Global Navigation Satellite Systems (GNSSs) provide free services such as the Galileo High-Accuracy Service (HAS) to enhance navigation precision. The Joint Research Centre (JRC) developed a monitoring system for HAS corrections from Galileo signals and the internet, comparing them with Multi-GNSS Experiment (MGEX) products. HAS is also exploited to compute daily position and timing solutions of IGS stations and JRC receivers. Performance is evaluated by analyzing HAS ephemeris errors and positioning accuracy considering single- and dual-constellation modes. Signal-in-space and Internet data distribution HAS corrections, their streams, and the derived experimental HAS products are stored at the JRC and made available for research. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 4167 KB

Open AccessProceeding Paper

Toward Context-Aware GNSS Positioning: A Preliminary Analysis

by Giovanni Cappello, Antonio Maratea, Ciro Gioia, Antonio Angrisano, Silvio Del Pizzo and Salvatore Gaglione

Eng. Proc. 2025, 88(1), 14; https://doi.org/10.3390/engproc2025088014 - 21 Mar 2025

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Abstract

The vast majority of GNSS users move in urban areas, where the signal conditions are highly unstable and multipath or gross errors make GNSS navigation unreliable or plainly unfeasible. In this study, features from real GNSS data collected by different grades of receivers [...] Read more.

The vast majority of GNSS users move in urban areas, where the signal conditions are highly unstable and multipath or gross errors make GNSS navigation unreliable or plainly unfeasible. In this study, features from real GNSS data collected by different grades of receivers have been compared to find candidate statistical indicators of the context that allow the automatic recognition of open sky or obstructed environments. The features considered are all pre-PVT and snapshot-based and hence suitable for real-time applications. They are namely the number of visible satellites, the dilution of precision, multipath linear combination with dual-frequency measurements, and the C/N0 difference between each couple of satellites in the same epoch at the same frequency. All measurements have been gathered both in open sky and in obstructed scenarios. The evidences suggest multipath linear combination and the C/N0 difference between couples of satellites as the most promising baselines for an environment classifier based on Machine Learning. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2560 KB

Open AccessProceeding Paper

Making a Good Thing Better: Jammertest 2023 Jamming, Meaconing, Spoofing, and Synchronization on the Norwegian Coast

by Aiden Morrison, Nadezda Sokolova, Nicolai Gerrard, Harald Hauglin, Thomas Rødningen and Anders Rødningsby

Eng. Proc. 2025, 88(1), 15; https://doi.org/10.3390/engproc2025088015 - 24 Mar 2025

Cited by 1 | Viewed by 1960

Abstract

Jammertest is the largest known GNSS jamming, meaconing, and spoofing test event in the world, which has an open policy towards both user participation and user communication with no restrictions on the sharing of data or publication of results. The organizers implemented several [...] Read more.

Jammertest is the largest known GNSS jamming, meaconing, and spoofing test event in the world, which has an open policy towards both user participation and user communication with no restrictions on the sharing of data or publication of results. The organizers implemented several changes and enhancements within the 2023 test campaign to further broaden the appeal and applicability of the tests for as many demographics of GNSS users as possible. More than 200 participants from 19 nations took part in person from 18 to 22 September at the test sites along the west coast of the Andøy island. This paper summarizes the design and motivation of the tests and test venue with particular attention to the efforts taken to provide users with precision timing and frequency references independent of the denied and disrupted GNSS signals. Aspects of surveilling and enforcing unintentional emissions, and real-time communication and coordination to the large number of distributed participants are also discussed. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 2383 KB

Open AccessProceeding Paper

WiFi–Round-Trip Timing (WiFi–RTT) Simultaneous Localisation and Mapping: Pedestrian Navigation in Unmapped Environments Using WiFi–RTT and Smartphone Inertial Sensors

by Khalil J. Raja and Paul D. Groves

Eng. Proc. 2025, 88(1), 16; https://doi.org/10.3390/engproc2025088016 - 24 Mar 2025

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Abstract

A core problem relating to indoor positioning is a lack of prior knowledge of the environment. To date, most WiFi–RTT research assumes knowledge of the access points in an indoor environment. This paper provides a solution to this problem by using a simultaneous [...] Read more.

A core problem relating to indoor positioning is a lack of prior knowledge of the environment. To date, most WiFi–RTT research assumes knowledge of the access points in an indoor environment. This paper provides a solution to this problem by using a simultaneous localisation and mapping (SLAM) algorithm, using WiFi–RTT and pedestrian dead reckoning, which uses the inertial sensors in a smartphone. A WiFi–RTT SLAM algorithm has only been researched in one instance at the time of writing; this paper aims to expand the exploration of this problem, particularly in relation to the use of outlier detection and motion models. For the trials, which were 35 steps long, the final mobile device horizontal positioning error was 1.01 m and 1.7 m for the forward and reverse trials, respectively. The results of this paper show that unmapped indoor positioning using WiFi–RTT is feasible for metre-level indoor positioning, given correct access point calibration. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 1633 KB

Open AccessProceeding Paper

Signal Design and Compatibility Assessment for LEO Navigation Augmentation System

by Tao Yan, Ying Wang, Lang Bian and Yansong Meng

Eng. Proc. 2025, 88(1), 17; https://doi.org/10.3390/engproc2025088017 - 25 Mar 2025

Viewed by 2407

Abstract

With the booming development of low earth orbit (LEO) satellite constellations, improving the global navigation satellite system (GNSS) performance based on LEO satellites is attracting more and more research attention. To shorten the convergence time of precise point positioning (PPP) with the help [...] Read more.

With the booming development of low earth orbit (LEO) satellite constellations, improving the global navigation satellite system (GNSS) performance based on LEO satellites is attracting more and more research attention. To shorten the convergence time of precise point positioning (PPP) with the help of the LEO navigation augmentation system, the dedicated LEO navigation augmentation signals need to be broadcasted, and the signals need to meet some special design requirements. This paper takes the GNSS L1 and L5 frequency bands as examples to design the LEO navigation augmentation signals. From the perspective of reducing interference to GNSS signals, the carrier frequency of the LEO navigation augmentation signal is selected, and the modulation type is designed. In order to support both high-precision measurement and high data rate, it is proposed that the LEO navigation signal consists of a measurement component and a data component with a high data rate. These two signal components are combined into one composite signal using the multiplexing code shift keying (MCSK) method. On this basis, compatibility between LEO navigation augmentation signals and GNSS signals is evaluated. The impact of LEO navigation augmentation signals on GNSS signals is further analyzed. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1430 KB

Open AccessProceeding Paper

Improvement of PNT Performances Using DLCNS in the Lunar Navigation System

by Andrea Massaccesi, Marco Fortunato, Jacopo Capolicchio and Lorenzo Marchionne

Eng. Proc. 2025, 88(1), 18; https://doi.org/10.3390/engproc2025088018 - 25 Mar 2025

Viewed by 916

Abstract

The increasing complexity of lunar exploration missions necessitates stricter navigation requirements, especially when human life is involved. Extensive research is currently being conducted on various positioning systems suitable for the lunar environment. These include both the exploitation of terrestrial GNSS (Global Navigation Satellite [...] Read more.

The increasing complexity of lunar exploration missions necessitates stricter navigation requirements, especially when human life is involved. Extensive research is currently being conducted on various positioning systems suitable for the lunar environment. These include both the exploitation of terrestrial GNSS (Global Navigation Satellite System) signals, and the deployment of a lunar-dedicated satellite system known as the Lunar Communication and Navigation Service (LCNS). In order to meet the demanding navigation requirements, the usage of one or more lunar beacons to enhance Positioning, Navigation, and Timing (PNT) performance for different assets is under investigation to complement the LCNS system. This research aims to demonstrate the improvement of PNT accuracy by exploiting Differential LCNS (DLCNS) positioning techniques. To this end, both Single Point Positioning (SPP) and DLCNS techniques along with estimation algorithms such as Weighted Least Squares (WLS) and Extended Kalman Filter (EKF) were developed in a simulated lunar environment to assess their performances. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2091 KB

Open AccessProceeding Paper

Early Detection of Coherent GNSS Spoofing Attacks with Cluster Analysis at Receiver Acquisition Stage

by Jan M. Becker

Eng. Proc. 2025, 88(1), 19; https://doi.org/10.3390/engproc2025088019 - 25 Mar 2025

Viewed by 2397

Abstract

The resilience of Global Navigation Satellite System (GNSS) usage against spoofing attacks can be increased by signal monitoring algorithms aiming to detect a spoofing signal at the acquisition stage of GNSS receiver signal processing. A common approach is to search for the presence [...] Read more.

The resilience of Global Navigation Satellite System (GNSS) usage against spoofing attacks can be increased by signal monitoring algorithms aiming to detect a spoofing signal at the acquisition stage of GNSS receiver signal processing. A common approach is to search for the presence of multiple correlation peaks in the absolute value of the Cross-Ambiguity Function (CAF). In this context, it is particularly challenging to detect spoofing signals with a correlation peak closely aligned to that of the authentic signal, as is the case at the early stage of a coherent spoofing attack. In the present work, a spoofing detection method is proposed that monitors the magnitude of the CAF by means of clustering techniques. It is designed to detect the pull-off during a coherent power-matched spoofing attack already at an early stage. The method is evaluated for the GPS L1 C/A signal based on a static scenario from the Texas Spoofing Test Battery (TEXBAT) data set as well as for the Galileo E1-B signal based on a real-world digital snapshot recording in the E1 frequency band that is augmented by emulated spoofing signals at the level of digital signal processing. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 2578 KB

Open AccessProceeding Paper

Concept of a Multi-Receiver-Vector Tracking Algorithm Within a Gnss Network

by Stefan Laller and Philipp Berglez

Eng. Proc. 2025, 88(1), 20; https://doi.org/10.3390/engproc2025088020 - 26 Mar 2025

Cited by 1 | Viewed by 1022

Abstract

This paper deals with the concept of a GNSS monitoring network, which fulfills requirements in relation to sustainability, cost efficiency and flexibility. For the proposed approach, the hardware of the GNSS monitoring stations should be reduced to a minimum. Therefore, Remote Radio Head [...] Read more.

This paper deals with the concept of a GNSS monitoring network, which fulfills requirements in relation to sustainability, cost efficiency and flexibility. For the proposed approach, the hardware of the GNSS monitoring stations should be reduced to a minimum. Therefore, Remote Radio Head sensors or especially RF Front-Ends, which are already used in the field of GNSS, should be used. In this concept, GNSS network stations are equipped with an antenna, an RF Front-End, and hardware for data transfer (raw I&Q samples) to a central processing facility. The idea is to realize a collaborative processing of all receivers with a Multi-Receiver-Vector Tracking (MRVT) algorithm in one single Software-Defined GNSS receiver (SDR). Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 4438 KB

Open AccessProceeding Paper

Impact of Solar Cycle 25 on GNSS Measurements: Analysis of Ionospheric Scintillation and Positioning Challenges

by Ali Broumandan, Isabelle Tremblay and Sandy Kennedy

Eng. Proc. 2025, 88(1), 21; https://doi.org/10.3390/engproc2025088021 - 26 Mar 2025

Cited by 6 | Viewed by 3187

Abstract

As the peak of solar cycle 25 approaches, increased ionospheric and scintillation activity is being observed, which is negatively impacting the quality of GNSS measurements and presenting challenges in the positioning domain. Ionospheric refraction and diffraction introduce delays and distortions to GNSS carrier [...] Read more.

As the peak of solar cycle 25 approaches, increased ionospheric and scintillation activity is being observed, which is negatively impacting the quality of GNSS measurements and presenting challenges in the positioning domain. Ionospheric refraction and diffraction introduce delays and distortions to GNSS carrier phase measurements, leading to positioning errors that exceed the anticipated accuracies. These position errors can be a significant concern for users across the world who depend on precise GNSS positioning, such as in agriculture, offshore marine positioning and autonomous automotive positioning. To understand the direct impact on NovAtel receivers and its positioning engines, a comprehensive analysis was conducted. A closer look was taken at what happened in 2023–2024 by characterizing scintillation using the amplitude scintillation index (S4) values in an equatorial region. Additionally, the scintillation effect on the receivers was characterized through the analysis of C/N0, lock breaks, double differences and other indicators. With a substantial amount of data collected at 20° latitude, where high solar activity occurs due to the proximity to the equator, the positioning performance of Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) was analyzed. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4307 KB

Open AccessProceeding Paper

Combined Navigation and Tracking with Applications to Low Earth Orbit Satellites

by Fabio Pisoni, Domenico Di Grazia, Giovanni Gogliettino, Thyagaraja Marathe, Paul Tarantino, Tyler Reid and Mathieu Favreau

Eng. Proc. 2025, 88(1), 22; https://doi.org/10.3390/engproc2025088022 - 28 Mar 2025

Cited by 2 | Viewed by 3359

Abstract

Low Earth Orbit (LEO) satellites complement classic GNSS by offering stronger signals, improved visibility, and system redundancy. Typical high speeds in LEO orbits generate rapid variations of the receiver-to-satellite geometry, which can improve the convergence of Precise Point Positioning (PPP) algorithms. However, high [...] Read more.

Low Earth Orbit (LEO) satellites complement classic GNSS by offering stronger signals, improved visibility, and system redundancy. Typical high speeds in LEO orbits generate rapid variations of the receiver-to-satellite geometry, which can improve the convergence of Precise Point Positioning (PPP) algorithms. However, high dynamics also induce strong Doppler rates at the receiver, which make the tracking procedures more difficult. In this paper, a loosely combined navigation and tracking architecture is applied to a Xona PULSAR™ Demonstration Signal in the L-Band such that the dynamic stress perceived by the receiver is mitigated. Other practical aspects of the Xona PULSAR™ receiver will be also discussed. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 6650 KB

Open AccessProceeding Paper

Real-Time Kinematic Positioning Using Multi-Frequency Smartphone Measurements

by Francesco Zanini, Melania Susi, Gabriele Losi and Dmitry Nikitin

Eng. Proc. 2025, 88(1), 23; https://doi.org/10.3390/engproc2025088023 - 28 Mar 2025

Cited by 1 | Viewed by 2706

Abstract

Nowadays, several smartphones on the market provide multi-frequency multi-constellations GNSS measurements, including carrier phase ones, allowing the achievement of high-accuracy positioning by exploiting Real Time Kinematic (RTK) or Precise Point Positioning (PPP) techniques. This paper will showcase the effectiveness of using smartphone measurements [...] Read more.

Nowadays, several smartphones on the market provide multi-frequency multi-constellations GNSS measurements, including carrier phase ones, allowing the achievement of high-accuracy positioning by exploiting Real Time Kinematic (RTK) or Precise Point Positioning (PPP) techniques. This paper will showcase the effectiveness of using smartphone measurements for RTK under different scenarios and for different applications using baselines of different lengths. The impact of the smartphone’s antenna on the solution will also be analysed. The assessment will be performed by evaluating different key performance indicators, including the time to first fix and the horizontal/vertical accuracy. This paper shows that around a 99% fix position can be achieved even using the smartphones’ antennas for the static case under open sky conditions. Moreover, high percentages of fix solutions can also be achieved in kinematic mode by ad hoc tuning of the RTK algorithm. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 5586 KB

Open AccessProceeding Paper

Investigation of Static and Kinematic Surveying Performance of Handheld GNSS Receiver

by Reha Metin Alkan, Serdar Erol, Bilal Mutlu and Muhammed Yahya Bıyık

Eng. Proc. 2025, 88(1), 24; https://doi.org/10.3390/engproc2025088024 - 28 Mar 2025

Cited by 1 | Viewed by 2015

Abstract

In this study, the static and kinematic positioning performance of the Garmin GPSMAP 66sr handheld GNSS receiver has been tested. For the static test, GNSS data was collected for 24 h and divided into shorter sessions of 1, 2, and 4 h to [...] Read more.

In this study, the static and kinematic positioning performance of the Garmin GPSMAP 66sr handheld GNSS receiver has been tested. For the static test, GNSS data was collected for 24 h and divided into shorter sessions of 1, 2, and 4 h to assess the performance of the receiver as a function of occupation time. The whole and subgroup data were processed by the relative method for different satellite constellations using three reference stations, to form a very short (45 m), short (5.1 km), and relatively long (73.2 km) baselines. For the kinematic test, the data was collected for approximately 1 h and processed with the relative method. Additionally, the whole and subgroup static and kinematic GNSS data of the Garmin receiver were also processed with the Canadian Spatial Reference System-Precise Point Positioning (CSRS-PPP) online service. All Garmin static and kinematic solutions (both relative and PPP) were compared with those calculated by the geodetic receiver. The overall static results show that the Garmin GPSMAP 66sr handheld receiver provides accuracy in a few centimeters with the relative method when integer ambiguities were correctly fixed and in the decimeter-to-meter level using the PPP technique. For the kinematic scenario, the results were relatively poor within the level of decimeters with the relative method while the level of meters with the PPP technique. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 2874 KB

Open AccessProceeding Paper

Analysis of GNSS Signal Correlation in Terrestrial Vehicles

by David Gómez-Casco, Xurxo Otero Villamide and Paolo Crosta

Eng. Proc. 2025, 88(1), 25; https://doi.org/10.3390/engproc2025088025 - 28 Mar 2025

Viewed by 1094

Abstract

This paper deals with the analysis of the distortion of the correlation functions in real vehicular scenarios. A multicorrelator GNSS receiver is used to process the data collected in urban and rural environments. Two methods are proposed to evaluate the distortion of the [...] Read more.

This paper deals with the analysis of the distortion of the correlation functions in real vehicular scenarios. A multicorrelator GNSS receiver is used to process the data collected in urban and rural environments. Two methods are proposed to evaluate the distortion of the correlation functions due to the presence of multipath. The first one consists of analyzing the error of the estimated correlation functions and the second one is based on estimating the multipath signals by implementing a Non-linear Least Squares (NLS) algorithm. The paper determines the number of reflected signals and assesses the differences and similarities between both scenarios. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 3200 KB

Open AccessProceeding Paper

GNSS Accuracy Under White Gaussian Noise Jamming

by Barend Lubbers

Eng. Proc. 2025, 88(1), 26; https://doi.org/10.3390/engproc2025088026 - 28 Mar 2025

Cited by 2 | Viewed by 2005

Abstract

The jamming of Global Navigation Satellite Systems (GNSSs) is now a major threat for GNSS-based Position, Navigation, and Timing (PNT) users. A jammed receiver will lose its fix at a certain distance and will not be able to provide PNT information. At greater [...] Read more.

The jamming of Global Navigation Satellite Systems (GNSSs) is now a major threat for GNSS-based Position, Navigation, and Timing (PNT) users. A jammed receiver will lose its fix at a certain distance and will not be able to provide PNT information. At greater distances, there will be a fix, so this PNT information can be obtained; however, the information will be less accurate, as the carrier-to-noise (

C / N_{0}

) ratios of the received signals will be suppressed by the jammer. In this paper, the pseudo-range accuracy of a GNSS receiver under jamming conditions is investigated in order to provide more insight into the effects of a jammer on the accuracy of a GNSS receiver. The theory available in the literature will be reviewed, after which this theory will be evaluated by comparing the theoretical results with actual measurements using a high-end GNSS signal simulator and a software-defined GNSS receiver. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 852 KB

Open AccessProceeding Paper

Advanced Receiver Autonomous Integrity Monitoring and Local Effect Models for Rail, Maritime, and Unmanned Aerial Vehicles Sectors

by Javier de Toro, Carlos Sanz, Elena Labrador, Roxana Clopot, Florin Mistrapau, Javier Fidalgo, Enrique Domínguez, Ginés Moreno, Fulgencio Buendía, Ana Cezón, Merle Snijders, Heiko Engwerda, Juliette Casals, Sophie Damy, Matteo Sgammini and Juan Pablo Boyero

Eng. Proc. 2025, 88(1), 27; https://doi.org/10.3390/engproc2025088027 - 31 Mar 2025

Viewed by 2203

Abstract

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) represents an advancement over RAIM, designed to utilize dual-frequency and multi-constellation technologies. Originally developed for aviation, the European Commission (EC) is now exploring its broader application. This paper examines the adaptation of ARAIM for rail, maritime, and [...] Read more.

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) represents an advancement over RAIM, designed to utilize dual-frequency and multi-constellation technologies. Originally developed for aviation, the European Commission (EC) is now exploring its broader application. This paper examines the adaptation of ARAIM for rail, maritime, and Unmanned Aerial Vehicles (UAVs) sectors. It briefly discusses aspects of the integrity concept, including architecture and user algorithms while the main focus is on characterizing local error models for local effects using real data campaigns. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1920 KB

Open AccessProceeding Paper

Radar-Altimeter Inertial Vertical Loop—Multisensor Estimation of Vertical Parameters for Autonomous Vertical Landing

by Tomas Vaispacher, Radek Baranek, Pavol Malinak, Vibhor Bageshwar and Daniel Bertrand

Eng. Proc. 2025, 88(1), 28; https://doi.org/10.3390/engproc2025088028 - 31 Mar 2025

Viewed by 3227

Abstract

The design, key functionalities, and performance requirements placed on modern aircraft navigation systems must adhere to the needs imposed by the progressively growing UAS/UAM and eVTOL segments, especially for terminal area operations in urban areas. This paper describes the design, implementation, and real-time [...] Read more.

The design, key functionalities, and performance requirements placed on modern aircraft navigation systems must adhere to the needs imposed by the progressively growing UAS/UAM and eVTOL segments, especially for terminal area operations in urban areas. This paper describes the design, implementation, and real-time validation of Honeywell’s Kalman filter-based radar-altimeter inertial vertical loop (RIVL) prototype. Inspired by the legacy of barometric altimeter-based technology, the RIVL prototype aims to provide high accuracy and integrity estimates of vertical parameters (altitude/height above ground and vertical velocity). The results from simulation tests, flight tests, and crane tests demonstrate that the vertical parameters estimated by the prototype satisfy vertical performance requirements across different terrains and scenarios. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 2773 KB

Open AccessProceeding Paper

Spatial Sensitivity of Navigation Using Signal-of-Opportunity (SoOP) from Starlink, Iridium-Next, GlobalStar, OneWeb, and Orbcomm Constellations

by Ahmad Esmaeilkhah and Rene Jr Landry

Eng. Proc. 2025, 88(1), 29; https://doi.org/10.3390/engproc2025088029 - 31 Mar 2025

Cited by 3 | Viewed by 4166

Abstract

This paper presents a thorough investigation into the EKF-based SoOP navigation algorithm’s sensitivity to spatial parameters and receiver- and transmitter-related properties. Utilizing the innovative SoOPNE simulation platform, our study unveils significant insights. For instance, at high latitudes, Iridium-Next, and Oneweb show a ten-fold [...] Read more.

This paper presents a thorough investigation into the EKF-based SoOP navigation algorithm’s sensitivity to spatial parameters and receiver- and transmitter-related properties. Utilizing the innovative SoOPNE simulation platform, our study unveils significant insights. For instance, at high latitudes, Iridium-Next, and Oneweb show a ten-fold accuracy improvement over Orbcomm. Additionally, discrepancies between predicted and actual satellite trajectories, with a nominal drift of approximately 250 m, result in navigation errors of around 400 m. Our findings underscore the critical importance of addressing these factors to optimize SoOP navigation performance. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 3571 KB

Open AccessProceeding Paper

Putting the Synthetic Global Navigation Satellite System Meta-Signal Paradigm into Practice: Application to Automotive Market Devices

by Domenico Di Grazia, Fabio Pisoni, Giovanni Gogliettino, Ciro Gioia and Daniele Borio

Eng. Proc. 2025, 88(1), 30; https://doi.org/10.3390/engproc2025088030 - 2 Apr 2025

Cited by 1 | Viewed by 1433

Abstract

The synthetic meta-signal reconstruction approach enables the generation of wideband Global Navigation Satellite System (GNSS) measurements from side-band observations. This approach is of particular interest for automotive market devices where, for instance, hardware constraints do not allow full-band Galileo Alternative Binary Offset Carrier [...] Read more.

The synthetic meta-signal reconstruction approach enables the generation of wideband Global Navigation Satellite System (GNSS) measurements from side-band observations. This approach is of particular interest for automotive market devices where, for instance, hardware constraints do not allow full-band Galileo Alternative Binary Offset Carrier (Alt-BOC) processing. In this paper, the applicability of the synthetic GNSS meta-signal paradigm is extended by introducing a half-cycle ambiguity detector for the reconstructed carrier phases and a jump detector for the pseudoranges. These accessories make the reconstruction approach more robust and suitable for mass market devices. Tests conducted using the STMicroelectronics TeseoV receiver demonstrate the validity and potential of this approach. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4642 KB

Open AccessProceeding Paper

Diversity Architecture for Robust GNSS/INS Navigation in Launcher Applications

by Fabio Scibona, Sergi Dueñas Pedrosa, Brendan David Polidori, Samuele Fantinato, Stefano Carletta, Paolo Teofilatto, Giovanni Palmerini and Eleftherios Plakidis

Eng. Proc. 2025, 88(1), 31; https://doi.org/10.3390/engproc2025088031 - 8 Apr 2025

Viewed by 1383

Abstract

The ESA DIVERGENCE (Diversity Architecture for Robust GNSS Receivers in Launcher Applications) project is focused on the design of a GNSS/INS hybrid navigation system and an appropriate FDIR/FDE algorithm for GNC applications in launchers and re-entry vehicles. The main goal is to demonstrate [...] Read more.

The ESA DIVERGENCE (Diversity Architecture for Robust GNSS Receivers in Launcher Applications) project is focused on the design of a GNSS/INS hybrid navigation system and an appropriate FDIR/FDE algorithm for GNC applications in launchers and re-entry vehicles. The main goal is to demonstrate architecture robustness with respect to possible threats and weaknesses introduced by GNSS and INS technology. A baseline navigation system architecture has been developed through a sensor fusion algorithm, which combines IMU, GNSS/DGNSS, a radar altimeter, and a star sensor to cover the accuracy requirements for all the flight phases. The navigation system has been designed to be easily adaptable to multiple applications, such as expendable launch vehicles, micro-launchers, reusable first stage boosters and unmanned re-entry vehicles. The most critical threats/failures were considered for the development of the FDIR/FDE algorithm, comprising GNSS signal outages, spoofing, satellite/receiver clock bias/drift discontinuities, IMU failures, saturation, vibration rectification, coning and sculling, and INS software numerical failures. A preliminary description of the implemented robust FDIR/FDE techniques is reported, and an analysis is conducted to compare the performance before and after FDIR/FDE algorithm implementation in a representative launcher scenario. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4034 KB

Open AccessProceeding Paper

Flight Test Results of Separation Assurance Methods for Joint Manned and Unmanned Aircraft Operations Using GNSS Measurement-Based ADS-L

by Benjamin Lochow, Anne-Sophie Polz, Vanessa Kempen and Maarten Uijt de Haag

Eng. Proc. 2025, 88(1), 32; https://doi.org/10.3390/engproc2025088032 - 8 Apr 2025

Viewed by 912

Abstract

This paper discusses a precise relative navigation and separation assurance system based on the exchange of Global Navigation Satellite (GNSS) measurements via new message types for Automatic Dependent Surveillance–Light (ADS-L). A measurement-based ADS-L implementation, which transmits raw measurements from the GNSS receiver rather [...] Read more.

This paper discusses a precise relative navigation and separation assurance system based on the exchange of Global Navigation Satellite (GNSS) measurements via new message types for Automatic Dependent Surveillance–Light (ADS-L). A measurement-based ADS-L implementation, which transmits raw measurements from the GNSS receiver rather than aircraft state vectors and performance parameters, is utilized to improve surveillance performance and add integrity to the surveillance solution. Furthermore, recent flight tests with one manned aircraft and two UASs are discussed, and the benefits of using GNSS measurement-based ADS-L data for separation assurance as opposed to traditional methods are reviewed. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 666 KB

Open AccessProceeding Paper

Galileo Timing Receiver Standard

by Héctor Llorca, Javier Fidalgo, Ricardo Píriz, Javier Bárcena, Francisco Arribas, Valeria Catalano, Gert-Jan Pauwels, Joaquim Fortuny, Beatrice Motella, Javier Tegedor, Matteo Sgammini, Miguel Aguilera, Juan Pablo Boyero and Tom Willems

Eng. Proc. 2025, 88(1), 33; https://doi.org/10.3390/engproc2025088033 - 9 Apr 2025

Viewed by 1828

Abstract

The European Commission (EC) is taking steps towards the implementation of a Galileo Timing Service. This service is now formally part of the mission of the Galileo Second Generation, and it puts emphasis on serving critical infrastructure. Implementing a proper service implies putting [...] Read more.

The European Commission (EC) is taking steps towards the implementation of a Galileo Timing Service. This service is now formally part of the mission of the Galileo Second Generation, and it puts emphasis on serving critical infrastructure. Implementing a proper service implies putting all the necessary elements in place to be able to meet the defined level of performance. In order to ensure the correct processing of the service’s signals and a minimum level of performance of the user receiver, corresponding standards are needed. Therefore, a fundamental element in the Galileo Timing Service concept is the standardization of Galileo Timing Receivers. The STARLITE project (Preparation of Standards for Galileo Timing Receivers) funded by the EC is the first international initiative to develop standards for GNSS Timing Receivers. The target users for the standard are all Galileo Timing users, with a special focus on critical infrastructure within the telecommunications, finance and energy sectors. The standard leverages the specificities of the Galileo Timing Service. This will become fundamental in order to ensure the end-to-end performance for those users operating a receiver compliant with the standard. At the same time, the standard allows the use of other systems to further enhance the performance. The project helped to establish a formal Working Group (WG9) for the development of the standard under CEN/CENELEC JTC5. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1082 KB

Open AccessProceeding Paper

Improving Structural Power Content Analysis Robustness for Satellite Navigation Applications

by Jelle Rijnsdorp and Andre Young

Eng. Proc. 2025, 88(1), 34; https://doi.org/10.3390/engproc2025088034 - 14 Apr 2025

Viewed by 712

Abstract

Many critical applications exhibit a growing dependency on Global Navigation Satellite Systems (GNSS), which has led to GNSS jamming and spoofing becoming an increasing threat to society. The Structural Power Content Analysis (SPCA) algorithm is a pre-despreading, low-complexity, and effective method to detect [...] Read more.

Many critical applications exhibit a growing dependency on Global Navigation Satellite Systems (GNSS), which has led to GNSS jamming and spoofing becoming an increasing threat to society. The Structural Power Content Analysis (SPCA) algorithm is a pre-despreading, low-complexity, and effective method to detect spoofing events, but in practice it is seen that false alarms are being generated in certain jamming scenarios. To mitigate these effects, alternative filtering techniques are evaluated and tested on both simulated data and publicly available spoofing datasets. Effective false alarm reduction with only a minor degradation in spoofing detection sensitivity is demonstrated. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 4122 KB

Open AccessProceeding Paper

UKSBAS Testbed Performance Assessment of Two Years of Operations

by Javier González Merino, Fernando Bravo Llano, Michael Pattinson, Madeleine Easom, Juan Ramón Campano Hernández, Ignacio Sanz Palomar, María Isabel Romero Llapa, Sangeetha Priya Ilamparithi, David Hill and George Newton

Eng. Proc. 2025, 88(1), 35; https://doi.org/10.3390/engproc2025088035 - 21 Apr 2025

Cited by 1 | Viewed by 1313

Abstract

Current Satellite-Based Augmentation Systems (SBASs) improve the positioning accuracy and integrity of GPS satellites and provide safe civil aviation navigation services for procedures from en-route to LPV-200 precision approach over specific regions. SBAS systems, such as WAAS, EGNOS, GAGAN, and MSAS, already operate. [...] Read more.

Current Satellite-Based Augmentation Systems (SBASs) improve the positioning accuracy and integrity of GPS satellites and provide safe civil aviation navigation services for procedures from en-route to LPV-200 precision approach over specific regions. SBAS systems, such as WAAS, EGNOS, GAGAN, and MSAS, already operate. The development of operational SBAS systems is in transition due to the extension of L1 SBAS services to new regions and the improvements expected by the introduction of dual frequency multi-constellation (DFMC) services, which allow the use of more core constellations such as Galileo and the use of ionosphere-free L1/L5 signal combination. The UKSBAS Testbed is a demonstration and feasibility project in the framework of ESA’s Navigation Innovation Support Programme (NAVISP), which is sponsored by the UK’s HMG with the participation of the Department for Transport and the UK Space Agency. UKSBAS Testbed’s main objective is to deliver a new L1 SBAS signal in space (SIS) from May 2022 in the UK region using Viasat’s Inmarsat-3F5 geostationary (GEO) satellite and Goonhilly Earth Station as signal uplink over PRN 158, as well as L1 SBAS and DFMC SBAS services through the Internet. SBAS messages are generated by GMV’s magicSBAS software and fed with data from the Ordnance Survey’s station network. This paper provides an assessment of the performance achieved by the UKSBAS Testbed during the last two years of operations at the SIS and user level, including a number of experimentation campaigns performed in the aviation and maritime domains, comprising ground tests at airports, flight tests on aircraft and sea trials on a vessel. This assessment includes, among others, service availability (e.g., APV-I, LPV-200), protection levels (PL), and position errors (PE) statistics over the service area and in a network of receivers. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2333 KB

Open AccessProceeding Paper

Assessment of Situational Awareness in Relation to Advanced Navigation Systems Using Ship Handling Simulators

by Hari Sundar Mahadevan, Ashwarya Kumar, Robert Grundmann and Anastasia Schwarze

Eng. Proc. 2025, 88(1), 36; https://doi.org/10.3390/engproc2025088036 - 25 Apr 2025

Cited by 1 | Viewed by 2856

Abstract

Digitalization has revolutionized the maritime industry, particularly in navigation systems. The use of advanced tools such as the Electronic Chart Display and Information System (ECDIS) has increased the need for information processing. However, the complexity of these systems can be overwhelming for navigators. [...] Read more.

Digitalization has revolutionized the maritime industry, particularly in navigation systems. The use of advanced tools such as the Electronic Chart Display and Information System (ECDIS) has increased the need for information processing. However, the complexity of these systems can be overwhelming for navigators. To address the concern of usability of these complex navigation systems, training with simulator data allows the crew to familiarize themselves with these systems, handle complex navigation scenarios effectively, support the transition from paper-based systems to digital systems, and help in improving their situational awareness (SA) at sea. We propose a tool that provides optimal conditions for assessing situational awareness and informing the development of intuitive systems and user interfaces. In the maritime safety domain, there is an inverse correlation between situational awareness and scenario/system complexity, highlighting the importance of effective training and assessments to improve SA. The proposed tool utilizes the Situational Awareness Global Assessment Technique (SAGAT) method, widely used in other domains, to calculate an individual’s SA score. It evaluates participants’ situational awareness in different navigational scenarios on Ship Handling Simulators, using dynamic questionnaires and contextual maps. Additionally, it integrates a rule-based system to assess participants’ performance and calculate a situational awareness score in real time, offering possibilities for assessing the SA of navigators. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 3058 KB

Open AccessProceeding Paper

Establishing Large-Scale Network PPP-RTK Through a Decentralized Architecture with a Common Pivot Station

by Cheolmin Lee, Sulgee Park and Sanghyun Park

Eng. Proc. 2025, 88(1), 37; https://doi.org/10.3390/engproc2025088037 - 30 Apr 2025

Viewed by 1000

Abstract

In this study, we introduce a decentralized architecture aimed at enhancing the efficiency of precise point positioning real-time kinematics (PPP-RTK) in large-scale networks with a common pivot station. Initially, we partition the extensive network into multiple smaller subnetworks (SNs), each with a common [...] Read more.

In this study, we introduce a decentralized architecture aimed at enhancing the efficiency of precise point positioning real-time kinematics (PPP-RTK) in large-scale networks with a common pivot station. Initially, we partition the extensive network into multiple smaller subnetworks (SNs), each with a common pivot station. The augmentation parameters for each SN are then computed using the precise orbit corrections and ionosphere-weighted constraints. However, directly applying the estimated augmentation parameters to users across subnetworks poses challenges due to inter-subnetwork discontinuities. These discontinuities arise from variations in the network configurations and the time correlation of the Kalman filters, despite the use of the same pivot station. To address this, common augmentation parameters, such as the satellite clocks and phase biases from each SN, are integrated into a unified set of parameters and broadcast to users. The aligned common augmentation parameters are then fed back into each SN, and the Kalman filter is re-updated to mitigate the inter-subnetwork discontinuities. The proposed architecture offers a reduced computational burden compared to the centralized PPP-RTK architecture, which handles a full-scale network simultaneously. Unlike previous research on decentralized PPP-RTK, the use of a common pivot station ensures a consistent basis for the common augmentation parameters. This approach enables seamless user positioning during transitions between SNs, eliminating the need to reset the user navigation filter during handover operations and simplifying the integration process. To evaluate the effectiveness of our proposed architecture, we gather dual-frequency global positioning system (GPS) observation data from over 40 continuously observed reference stations (CORSs) in Korea. These data are then partitioned into four SNs, each sharing a common pivot station. Subsequently, we compare the static positioning error and processing time of our proposed architecture with those of the centralized architecture. Additionally, the mitigation performance of the inter-network discontinuities is shown. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2968 KB

Open AccessProceeding Paper

Performance Analysis of Spoofing and Interference Detection Techniques for Satellite-Based Augmentation System and Global Navigation Satellite System Reference Receivers

by Xavier Álvarez-Molina, Gonzalo Seco-Granados, Marc Solé-Gaset, Sergi Locubiche-Serra and José A. López-Salcedo

Eng. Proc. 2025, 88(1), 38; https://doi.org/10.3390/engproc2025088038 - 29 Apr 2025

Cited by 1 | Viewed by 1969

Abstract

Global Navigation Satellite System (GNSS) reference receivers are an essential part of ground stations that make the operation of Satellite-Based Augmentation Systems (SBAS) possible. Recently, there has been increasing concern about spoofing and interference events, which may seriously hinder the operation of GNSS [...] Read more.

Global Navigation Satellite System (GNSS) reference receivers are an essential part of ground stations that make the operation of Satellite-Based Augmentation Systems (SBAS) possible. Recently, there has been increasing concern about spoofing and interference events, which may seriously hinder the operation of GNSS receivers in liability- and safety-critical applications and, in particular, SBAS ground stations. In this context, the goal of this paper is two-fold. On the one hand, a set of spoofing and interference detection techniques should be presented specifically tailored to operate with the outputs provided by a NovAtel G-III SBAS reference receiver. On the other hand, assessing these techniques with various tests conducted using a Safran Skydel GSG-8 GNSS RF simulator in order to validate their implementation and effectiveness is necessary. This work concludes with an analysis of the obtained results, providing insightful recommendations and guidelines. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1265 KB

Open AccessProceeding Paper

Indoor Signal Strength Evaluation of the Orbcomm Low Earth Orbit Satellite Constellation

by Wout Van Uytsel, Thomas Janssen, Maarten Weyn and Rafael Berkvens

Eng. Proc. 2025, 88(1), 39; https://doi.org/10.3390/engproc2025088039 - 29 Apr 2025

Cited by 1 | Viewed by 3256

Abstract

In this connected world, communication in all kinds of complex environments is crucial. As a result, indoor satellite communication could enable many new applications and use cases. In this study, we explore the potential of Low Earth Orbit (LEO) satellites to provide indoor [...] Read more.

In this connected world, communication in all kinds of complex environments is crucial. As a result, indoor satellite communication could enable many new applications and use cases. In this study, we explore the potential of Low Earth Orbit (LEO) satellites to provide indoor coverage. This is done by evaluating the signal strength of Orbcomm LEO satellite signals in multiple indoor environments within a suburban home. Starting from IQ samples, we developed an algorithm to calculate the Carrier-to-Noise Density Ratio (C/N0) as a key performance metric to compare environments when the Carrier-To-Noise Ratio (CNR) is above 0 dB. By utilizing a Software Defined Radio (SDR) in combination with this algorithm, we were able to evaluate the signal strength differences between environments. We found that the LEO satellite signals penetrated into every environment including the basement. The signals were even received with high signal strength in the attic, reaching values above 55 dB-Hz. Moreover, the signals were well received in every above-ground environment. Unsurprisingly, the satellite signals were received the weakest in the basement and only for a short duration of time. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 906 KB

Open AccessProceeding Paper

Evaluation and Simulation of Ultra-Wide Band (UWB) Transceiver Timebases

by Václav Navrátil and Josef Krška

Eng. Proc. 2025, 88(1), 40; https://doi.org/10.3390/engproc2025088040 - 29 Apr 2025

Viewed by 1638

Abstract

Ultra-Wide Band (UWB) real-time localization systems usually require either precise and robust synchronization of the anchor transceivers or sufficiently stable clocks for methods referred to as “synchronization-free”. Typically, reasonably priced crystals or TCXOs are utilized as frequency references for the UWB transceivers. Clock [...] Read more.

Ultra-Wide Band (UWB) real-time localization systems usually require either precise and robust synchronization of the anchor transceivers or sufficiently stable clocks for methods referred to as “synchronization-free”. Typically, reasonably priced crystals or TCXOs are utilized as frequency references for the UWB transceivers. Clock characterization and simulation are necessary to evaluate and tune the synchronization or positioning algorithms without the need of hardware-pulling of the UWB reference oscillators. In this paper, the method of transceiver clock stability measurement is presented, and several modules with various clock sources are evaluated. As a reference, a UWB module with a clock derived from a Caesium standard is utilized. A method for simulating typical timestamp-series errors attributed to UWB transceiver clocks is provided as well. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 1163 KB

Open AccessProceeding Paper

Deriving a Dilution of Precision Indicator for GNSS Factor Graph Optimization Solutions

by Paul Thevenon, Hakim Cherfi and Julien Lesouple

Eng. Proc. 2025, 88(1), 41; https://doi.org/10.3390/engproc2025088041 - 30 Apr 2025

Cited by 1 | Viewed by 1272

Abstract

Dilution of Precision (DOP) is routinely used in GNSS to assess the quality of the constellation geometry for the positioning algorithm. Those DOP indicators are computed from the estimation covariance of a snapshot weighted least squares (WLS) estimate under certain hypotheses. This paper [...] Read more.

Dilution of Precision (DOP) is routinely used in GNSS to assess the quality of the constellation geometry for the positioning algorithm. Those DOP indicators are computed from the estimation covariance of a snapshot weighted least squares (WLS) estimate under certain hypotheses. This paper proposes to define DOP indicators for GNSS solutions based on Factor Graph Optimization (FGO). FGO solutions have become popular in the GNSS domain. They allow to easily model probabilistic contraints, called factors, over a large time window, by mixing observations and motion constraints accross consecutive epochs. The solution is solved by performing a batch WLS estimation for the states at all considered epochs, using all available factors. Due to the simple nature of the estimation algorithm—a WLS solution—it is possible to derive the theoretical estimation error covariance, which will indicate the accuracy of the computed solution. In this paper, a formula is proposed to approximate the DOP for the FGO solution. Then, the formula is validated in various scenarios involving fixed or changing satellite visibility. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 3582 KB

Open AccessProceeding Paper

Analysis and Validation of Distributed GNSS Spoofing Threat

by Minghan Zhong, Hong Li and Mingquan Lu

Eng. Proc. 2025, 88(1), 42; https://doi.org/10.3390/engproc2025088042 - 6 May 2025

Cited by 5 | Viewed by 1661

Abstract

This paper delves into the distributed GNSS spoofing threat, a sophisticated deployment structure wherein multiple spoofing antennas each emit a single spoofing signal to the victim receiver. This study analyzes the challenges associated with executing distributed spoofing and proposes potential structures to address [...] Read more.

This paper delves into the distributed GNSS spoofing threat, a sophisticated deployment structure wherein multiple spoofing antennas each emit a single spoofing signal to the victim receiver. This study analyzes the challenges associated with executing distributed spoofing and proposes potential structures to address them. To validate the distributed spoofing threat, an experimental platform is designed specifically for distributed spoofing. Field test results confirm that distributed spoofing can effectively manipulate the victim’s PVT solution, underscoring the potential hazard of this sophisticated GNSS spoofing threat. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2834 KB

Open AccessProceeding Paper

UWB-Based Positioning Is Not Invulnerable from Spoofing Attacks: A Case Study of Crazyswarm

by Mahyar Shariat, Jelena Gabela Majić, Max Brandstätter and Wolfgang Kastner

Eng. Proc. 2025, 88(1), 43; https://doi.org/10.3390/engproc2025088043 - 7 May 2025

Viewed by 1854

Abstract

Spoofing attacks pose a threat to drones, which can lead to their crash or takeover. As a countermeasure, the European Space Agency has implemented the Timed Efficient Loss-tolerant Authentication (TESLA) broadcast protocol in the Galileo Open Service Navigation Message Authentication (OSNMA) to detect [...] Read more.

Spoofing attacks pose a threat to drones, which can lead to their crash or takeover. As a countermeasure, the European Space Agency has implemented the Timed Efficient Loss-tolerant Authentication (TESLA) broadcast protocol in the Galileo Open Service Navigation Message Authentication (OSNMA) to detect such events. This study explores the application of TESLA in detecting spoofing attacks targeted at drone swarms that rely on positioning systems utilizing ultra-wideband (UWB) technology. The results of our experiments reaffirm that UWB-based positioning systems are not automatically invulnerable from spoofing attacks and that cryptographic methods such as TESLA are required to provide a layer of protection against spoofing attacks to detect them effectively. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 2181 KB

Open AccessProceeding Paper

Integrating Multi-Sensor Augmented PNT to Enhance Outdoor Human Motion Capture Using Low-Cost GNSS Receivers

by Andrea Maffia, Georgii Kurshakov, Tiziano Cosso, Vittorio Sanguineti and Giorgio Delzanno

Eng. Proc. 2025, 88(1), 44; https://doi.org/10.3390/engproc2025088044 - 8 May 2025

Viewed by 1246

Abstract

We are working on an innovative approach to outdoor human motion capture, using a wearable device that integrates a low-cost GNSS (Global Navigation Satellite System) receiver and an INS (Inertial Navigation System) via a zero-velocity update (ZUPT) methodology. In this study, we focused [...] Read more.

We are working on an innovative approach to outdoor human motion capture, using a wearable device that integrates a low-cost GNSS (Global Navigation Satellite System) receiver and an INS (Inertial Navigation System) via a zero-velocity update (ZUPT) methodology. In this study, we focused on using these devices to reconstruct the foot trajectory. Our work addresses the challenge of capturing precise foot movements in uncontrolled outdoor environments, a task traditionally constrained by the limitations of laboratory settings. We equipped devices that combine inertial measurement units (IMUs) with GNSS receivers in the following configuration: one on each foot and one on the head. We experimented with different GNSS data processing techniques, such as Post-Processed Kinematic (PPK) positioning with and without Moving Base (MB), and after the integration with the IMU, we obtained centimeter-level precision in horizontal and vertical positioning for various walking speeds. This integration leverages a loosely coupled GNSS/INS approach, where the GNSS solution is independently processed and subsequently used to refine the INS outputs. Enhanced by ZUPT and Madgwick filtering, this method significantly improves the trajectory reconstruction accuracy. Indeed, our research includes a study of the impact of moving speed on the performance of these low-cost GNSS receivers. These insights pave the way for future exploration into tightly coupled GNSS/INS integration using low-cost GNSS receivers, promising advancements in fields like sports science, rehabilitation, and well-being. This work seeks not only to contribute to the field of wearable technology, but also to open possibilities for further innovation in affordable, high-accuracy personal navigation and activity monitoring devices. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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7 pages, 3448 KB

Open AccessProceeding Paper

Two-Stage Beamforming Technique for GNSS Applications

by Noori BniLam, Samah Chazbeck, Szabolcs Berki, Raffaele Fiengo and Paolo Crosta

Eng. Proc. 2025, 88(1), 45; https://doi.org/10.3390/engproc2025088045 - 9 May 2025

Cited by 1 | Viewed by 1862

Abstract

In this paper, we introduce a robust beamforming technique using array antennas. The proposed solution constitutes two stages; the first stage exploits the space-alternating generalized expectation-maximization (SAGE) algorithm to decompose the received GNSS signal into its constituent signals, i.e., direct and reflected signals. [...] Read more.

In this paper, we introduce a robust beamforming technique using array antennas. The proposed solution constitutes two stages; the first stage exploits the space-alternating generalized expectation-maximization (SAGE) algorithm to decompose the received GNSS signal into its constituent signals, i.e., direct and reflected signals. The SAGE algorithm estimates the angle of arrival (AoA) and the received covariance matrix for both the direct and reflected signals. The second stage, on the other hand, utilizes the Minimum Variance Distortionless Response (MVDR) algorithm to produce the weight vector that steers the main beam towards the satellite’s direction and the nulls towards the multipath effect. The MVDR uses the AoA of the direct path and the covariance matrix of the reflected path to minimize the multipath effect. The experimental results reveal that the proposed technique improves the received signal strength and the location estimation accuracy, as compared to a single-antenna system. Furthermore, the proposed technique outperforms the traditional MVDR technique in the tested environment. Finally, the 95% 3D position error of the proposed solution is 5.2 m, and the position dilution of precision (pdop) is 0.84. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1714 KB

Open AccessProceeding Paper

Efficient Detection of Galileo SAS Sequences Using E6-B Aiding

by Rafael Terris-Gallego, Ignacio Fernandez-Hernandez, José A. López-Salcedo and Gonzalo Seco-Granados

Eng. Proc. 2025, 88(1), 46; https://doi.org/10.3390/engproc2025088046 - 9 May 2025

Cited by 1 | Viewed by 1495

Abstract

Galileo Signal Authentication Service (SAS) is an assisted signal authentication capability under development by Galileo, designed to enhance the robustness of the European Global Navigation Satellite System (GNSS) against malicious attacks like spoofing. It operates by providing information about some fragments of the [...] Read more.

Galileo Signal Authentication Service (SAS) is an assisted signal authentication capability under development by Galileo, designed to enhance the robustness of the European Global Navigation Satellite System (GNSS) against malicious attacks like spoofing. It operates by providing information about some fragments of the unknown spreading codes in the E6-C signal. Unlike other approaches, Galileo SAS uniquely employs Timed Efficient Stream Loss-tolerant Authentication (TESLA) keys provided by Open Service Navigation Message Authentication (OSNMA) in the E1-B signal for decryption, avoiding the need for key storage in potentially compromised receivers. The encrypted fragments are made available to the receivers before the broadcast of the E6-C signal, along with their broadcast time. However, if the receiver lacks an accurate time reference, searching for these fragments—which typically last for milliseconds and have periodicities extending to several seconds—can become impractical. In such cases, the probability of detection is severely diminished due to the excessively large search space that results. To mitigate this, initial estimates for the code phase delay and Doppler frequency can be obtained from the E1-B signal. Nevertheless, the alignment between E1-B and E6-C is not perfect, largely due to the intrinsic inter-frequency biases they exhibit. To mitigate this issue, we can leverage auxiliary signals like E6-B, processed by High Accuracy Service (HAS)-compatible receivers. This is a logical choice as E6-B shares the same carrier frequency as E6-C. This could help in obtaining more precise estimates of the location of the encrypted fragments and improving the probability of detection, resulting in enhanced robustness for the SAS authentication process. This paper presents a comparison of uncertainties associated with the use of the E1-B and E6-B signals, based on real data samples obtained with a custom-built Galileo SAS evaluation platform based on Software Defined Radio (SDR) boards. The results show the benefits of including E6-B in SAS processing, with minimal implementation cost. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 781 KB

Open AccessProceeding Paper

Study of Proposed SIS Monitoring Strategies for a Lunar Navigation System

by Daniele Musacchio, Laura De Leo and Mattia Carosi

Eng. Proc. 2025, 88(1), 47; https://doi.org/10.3390/engproc2025088047 - 9 May 2025

Viewed by 783

Abstract

The deployment of a lunar navigation satellite system will be justified by the provision of navigation services to the many planned lunar missions that will include both orbiting and surface users. In this context, system monitoring and system validation will require an innovative [...] Read more.

The deployment of a lunar navigation satellite system will be justified by the provision of navigation services to the many planned lunar missions that will include both orbiting and surface users. In this context, system monitoring and system validation will require an innovative approach different from common GNSS terrestrial application, considering the initial absence of a ground station on the lunar surface. A trade-off will be performed between three proposed strategies for the monitoring of navigation signals broadcasted by lunar-orbiting satellites, considering the advantages and disadvantages and proposing the best strategy to verify the structure and/or content of the navigation signal. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 3265 KB

Open AccessProceeding Paper

IEC-61108-7 SBAS Standard for Shipborne Receivers: Preliminary Testing Validation Activities

by Javier Tegedor, Joaquim Fortuny, Guillermo Fernandez, Elisabet Lacarra, Ettore Canestri, Silvia Porfili and Ciro Gioia

Eng. Proc. 2025, 88(1), 48; https://doi.org/10.3390/engproc2025088048 - 12 May 2025

Cited by 1 | Viewed by 1669

Abstract

The IEC 61108-7 standard focuses on the minimum performance required by shipborne receivers using satellite-based augmentation system (SBAS) L1 signals to be compliant with the performance specified in IMO Resolution A.1046(27). Apart from the minimum performance requirements, the standard specifies the testing methods [...] Read more.

The IEC 61108-7 standard focuses on the minimum performance required by shipborne receivers using satellite-based augmentation system (SBAS) L1 signals to be compliant with the performance specified in IMO Resolution A.1046(27). Apart from the minimum performance requirements, the standard specifies the testing methods and a full set of scenarios with their pass/fail criteria. To verify the feasibility of the tests defined in the standard, a comprehensive test campaign was carried out in a joint effort by the European Satellite Services Provider (ESSP) and the European Commission’s Joint Research Centre (JRC) under the coordination of the European Union Agency for the Space Programme (EUSPA). This paper presents an assessment of the validity and appropriateness of the test scenarios and the minimum performance requirements specified in the IEC-61108-7 standard. To conduct the campaign, dedicated setups were designed and implemented at the JRC and ESSP laboratories, where live and simulated GPS+SBAS signals were used. For the analysis, all the test cases (TCs) described in the standard were implemented, and two commercial devices were tested. From the results, it emerged that all the TCs were properly designed and implemented, thereby confirming the feasibility of the tests defined in IEC 61108-7. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1948 KB

Open AccessProceeding Paper

Exploitation of 5G, LTE, and Automatic Identification System Signals for Fallback Unmanned Aerial Vehicle Navigation

by Adrian Winter, Aiden Morrison, Oliver Hasler and Nadezda Sokolova

Eng. Proc. 2025, 88(1), 49; https://doi.org/10.3390/engproc2025088049 - 13 May 2025

Cited by 2 | Viewed by 1607

Abstract

Reliable Position, Navigation, and Timing (PNT) is becoming more and more important, considering the proliferation of highly autonomous safety- and liability-critical systems. Due to their vulnerability to various threats such as deliberate Radio Frequency Interference (RFI), including jamming, spoofing, and others, there is [...] Read more.

Reliable Position, Navigation, and Timing (PNT) is becoming more and more important, considering the proliferation of highly autonomous safety- and liability-critical systems. Due to their vulnerability to various threats such as deliberate Radio Frequency Interference (RFI), including jamming, spoofing, and others, there is significant research into finding backup/fallback solutions that allow safe mission completion or termination. This work compares two such systems: one based on Angle of Arrival (AoA) measurement and one based on cellular (4G and 5G) signals. The results are generated using simulations, which are substantiated by real-world performance measurements. It is shown that both systems have the potential to serve as backup navigation solutions and that the cellular system outperforms the AoA-based solution, albeit at a much higher price and with higher computational requirements. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1156 KB

Open AccessProceeding Paper

In-Band Medium-Frequency R-Mode Signal Quality Estimation ^†

by Filippo Giacomo Rizzi, Lars Grundhöfer, Niklas Hehenkamp, Stefan Gewies, Daniel Medina and Juan Manuel Gandarias

Eng. Proc. 2025, 88(1), 50; https://doi.org/10.3390/engproc2025088050 - 13 May 2025

Cited by 1 | Viewed by 736

Abstract

Assessing the quality of a received signal is of fundamental importance to predict the performance of the receiver. In general, the signal to noise ratio (SNR) or the carrier to noise density

C / N_{0}

ratio is used as an indicator to [...] Read more.

Assessing the quality of a received signal is of fundamental importance to predict the performance of the receiver. In general, the signal to noise ratio (SNR) or the carrier to noise density

C / N_{0}

ratio is used as an indicator to describe the signal quality of most receivers. For the medium-frequency (MF) R-Mode, a terrestrial positioning navigation and timing (PNT) system, the knowledge of the SNR or

C / N_{0}

is important for monitoring purposes, helping the service operator to assess the healthiness of the transmitted signals, as well as for the users to optimize the receiver algorithms and performance. In this paper, we present how the

C / N_{0}

can be estimated from the output of the discrete Fourier transform (DFT). The DFT is already used in the receiver to perform the phase estimation; hence, the receiver computational load is reduced. Theory is first presented and discussed, followed by the definition of the estimator, which is tested with Monte Carlo simulation as well as with real data to validate the approach. The results show good agreement between theory, simulation, and in-field measurements, which proves that the estimated

C / N_{0}

is a good indicator to measure the received signal quality under optimal propagation condition. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 1729 KB

Open AccessProceeding Paper

On the Edge Model-Aided Machine Learning GNSS Interference Classification with Low-Cost COTS Hardware

by Simon Kocher, David Contreras Franco, Antonia Dietz and Alexander Rügamer

Eng. Proc. 2025, 88(1), 51; https://doi.org/10.3390/engproc2025088051 - 14 May 2025

Viewed by 1922

Abstract

Interference signals can disrupt global navigation satellite system (GNSS) receivers and degrade or deny a position-velocity-time (PVT) solution. After detecting an interference signal, classifying its type can provide insight into its cause and help determine the necessary next steps to counteract it. In [...] Read more.

Interference signals can disrupt global navigation satellite system (GNSS) receivers and degrade or deny a position-velocity-time (PVT) solution. After detecting an interference signal, classifying its type can provide insight into its cause and help determine the necessary next steps to counteract it. In this paper, we present a method for interference detection and a resource-efficient model-aided on-the-edge machine learning (ML) model for interference signal classification running on low-cost commercial-off-the-shelf (COTS) hardware, enabling a highly cost-effective spectral monitoring solution. The choice of detection metrics is justified based on real-world spectral monitoring data from a German highway and the capability of the ML model to generalize across different environments is demonstrated in an outdoor field test. Overall, we present an operationally ready GNSS interference detection and classification system. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 803 KB

Open AccessProceeding Paper

A Novel Navigation Message for Future LCNS Satellites

by Filipe De Oliveira Salgueiro, Floor Thomas Melman, Richard Swinden, Yoann Audet, Pietro Giordano and Javier Ventura-Traveset

Eng. Proc. 2025, 88(1), 52; https://doi.org/10.3390/engproc2025088052 - 14 May 2025

Cited by 1 | Viewed by 1956

Abstract

With the renewed interest in the Moon, several countries are launching projects to explore the Moon (at both institutional and private level). As part of the Moonlight Programme, the European Space Agency (ESA) is developing Lunar Communication and Navigation Services (LCNS) with its [...] Read more.

With the renewed interest in the Moon, several countries are launching projects to explore the Moon (at both institutional and private level). As part of the Moonlight Programme, the European Space Agency (ESA) is developing Lunar Communication and Navigation Services (LCNS) with its industrial partners. The Moon orbits, specifically the Elliptical Lunar Frozen Orbits (ELFO), are quite different compared to the GNSS orbits. This work presents a novel orbit model for the LCNS that can support different ELFOs and other orbits. The performance of the new model is measured in terms of accuracy and the number of bits (required to broadcast the information) against other available models. Such a model could be used to broadcast the ephemeris of the LCNS satellites within the navigation message of the LunaNet Augmented Forward Signal (AFS). Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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13 pages, 6636 KB

Open AccessProceeding Paper

Estimation of the Effect of Single Source of RF Interference on an Airborne Global Navigation Satellite System Receiver: A Theoretical Study and Parametric Simulation

by Ahmad Esmaeilkhah and Rene Jr Landry

Eng. Proc. 2025, 88(1), 53; https://doi.org/10.3390/engproc2025088053 - 14 May 2025

Cited by 2 | Viewed by 920

Abstract

This paper addresses the critical issue of unwanted interference in airborne GNSS receivers, crucial for navigational safety. Previous studies often simplified the problem, but this work offers a comprehensive approach, considering factors like Earth’s reflective properties, 3D calculations, and distinct radiation patterns. It [...] Read more.

This paper addresses the critical issue of unwanted interference in airborne GNSS receivers, crucial for navigational safety. Previous studies often simplified the problem, but this work offers a comprehensive approach, considering factors like Earth’s reflective properties, 3D calculations, and distinct radiation patterns. It introduces Spatial Interference Distribution Expression Heat-map and Operation Efficacy Plot graphs to visualize interference distribution along flight paths. The results highlight the significance of physical configuration and distance from interference sources on receiver performance. The algorithm developed can assess interference effects on GNSS receivers and aid in selecting optimal flight paths for minimal interference. This research enhances understanding and management of unintentional interference in airborne navigation systems. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 2822 KB

Open AccessProceeding Paper

Performance Analysis of CUDA-Based Galileo Signal Quality Monitoring

by Florian Binder, Daniel J. Bauer, Thomas Pany and Torben Schüler

Eng. Proc. 2025, 88(1), 54; https://doi.org/10.3390/engproc2025088054 - 15 May 2025

Cited by 1 | Viewed by 821

Abstract

The aim of this study was to develop basic findings for a continuous Signal Quality Monitoring system based on a measurement campaign. Four Galileo satellites were repeatedly recorded, using a dish antenna, and their metrics were analyzed. Due to the stable course, thresholds [...] Read more.

The aim of this study was to develop basic findings for a continuous Signal Quality Monitoring system based on a measurement campaign. Four Galileo satellites were repeatedly recorded, using a dish antenna, and their metrics were analyzed. Due to the stable course, thresholds for the detection of threat models can be determined. These values were tested against simulated signals and the sensitivity of the detection was found to be satisfactory. Based on the convergence behavior of the data, a measurement duration of 180–200 s can be recommended. Finally, the influence of the GPU and memory clock on the performance of predefined conditions close to the receiver was tested. The core clock of the GPU was identified as the bottleneck of the processing. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 11179 KB

Open AccessProceeding Paper

GNSS Jamming Observed on Sounding Rocket Flights from Northern Scandinavia

by Benjamin Braun, Oliver Montenbruck, Markus Markgraf, Marcus Hörschgen-Eggers and Rainer Kirchhartz

Eng. Proc. 2025, 88(1), 55; https://doi.org/10.3390/engproc2025088055 - 16 May 2025

Cited by 1 | Viewed by 3081

Abstract

Since 2022, DLR’s Mobile Rocket Base (MORABA) has observed jamming of GNSS signals on sounding rockets launched from Esrange in northern Sweden and Andøya Space Center (ASC) in northern Norway. The jamming primarily affected the GPS L1, Galileo E1 and BeiDou B1C and [...] Read more.

Since 2022, DLR’s Mobile Rocket Base (MORABA) has observed jamming of GNSS signals on sounding rockets launched from Esrange in northern Sweden and Andøya Space Center (ASC) in northern Norway. The jamming primarily affected the GPS L1, Galileo E1 and BeiDou B1C and B1I signals on the L1 frequency band and was noticeable through a pronounced reduction in the carrier-to-noise ratio of the received GNSS signals. Jamming was observed in northern Sweden at an altitude above 22 km and in northern Norway at an altitude above 36 km. Geometric considerations made it possible to roughly localize the source of the jamming signals from the points of the flight path marking the start and end of interference. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 4185 KB

Open AccessProceeding Paper

Enhancing GNSS PPP Algorithms with AI: Towards Mitigating Multipath Effects

by Álvaro Tena, Adrián Chamorro and Jesús David Calle

Eng. Proc. 2025, 88(1), 56; https://doi.org/10.3390/engproc2025088056 - 19 May 2025

Cited by 1 | Viewed by 2863

Abstract

Nowadays, high precision and reliability of Global Navigation Satellite Systems are increasingly important in positioning applications. Machine learning is used to improve the performance of the GSHARP PPP algorithm by reducing the effect of multipath on GNSS measurements. The clustering analysis is conducted [...] Read more.

Nowadays, high precision and reliability of Global Navigation Satellite Systems are increasingly important in positioning applications. Machine learning is used to improve the performance of the GSHARP PPP algorithm by reducing the effect of multipath on GNSS measurements. The clustering analysis is conducted on the primary GNSS data points with the goal of discovering and analyzing patterns in the multipath interference. This study represents an early attempt to apply AI to the GSHARP PPP algorithm. Since Lightweight Machine Learning is used in this research, it is easier to integrate and might lay the groundwork for future integration of advanced deep learning methods. About 50 h of data collected from different environments (e.g., highways and urban areas) serves as the training data for these algorithms, which ensures their robustness and real-world applicability. The use of machine learning clustering inside the PPP algorithm serves as a way to improve its performance against multipath effects, as well as provide a platform for subsequent development of precision GNSS systems through AI technologies. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4421 KB

Open AccessProceeding Paper

Geometric Analysis of LEO-Based Monitoring of GNSS Constellations

by Can Oezmaden, Omar García Crespillo, Michael Niestroj, Marius Brachvogel and Michael Meurer

Eng. Proc. 2025, 88(1), 57; https://doi.org/10.3390/engproc2025088057 - 19 May 2025

Cited by 2 | Viewed by 2756

Abstract

The last decade has seen a surge in the development and deployment of low Earth orbit (LEO) constellations primarily serving broadband communication applications. These developments have also influenced the interest providing positioning, navigation, and timing (PNT) services from LEO. Potential services include new [...] Read more.

The last decade has seen a surge in the development and deployment of low Earth orbit (LEO) constellations primarily serving broadband communication applications. These developments have also influenced the interest providing positioning, navigation, and timing (PNT) services from LEO. Potential services include new ranging signals from LEO, augmentation of global navigation satellite systems (GNSS), and monitoring of GNSS. The latter promises an advantage over existing ground-based monitoring due to the reception of observables with reduced atmospheric error contributions and the potential for lower costs. In this paper, we investigate the influence of LEO constellation design on the line-of-sight visibility conditions for GNSS monitoring. We simulate a series of Walker constellations in LEO with a varying number of total satellites, orbital planes, and orbital heights. From the simulated data, we gather statistics on the number of visible GNSS and LEO satellites, durations of visibility periods, and the quality of this visibility quantified by the dilution of precision (DOP) metric. Our findings indicate that increasing the total number of LEO satellites results in diminishing returns. We find that constellations with relatively few total satellites equally yield an adequate monitoring capability. We also identify orbital geometric constraints resulting in suboptimal performance and discuss optimization strategies. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2559 KB

Open AccessProceeding Paper

An End-To-End Solution Towards Authenticated Positioning Utilizing Open-Source FGI-GSRx and FGI-OSNMA

by Muwahida Liaquat, Mohammad Zahidul H. Bhuiyan, Toni Hammarberg, Saiful Islam, Mika Saajasto and Sanna Kaasalainen

Eng. Proc. 2025, 88(1), 58; https://doi.org/10.3390/engproc2025088058 - 19 May 2025

Viewed by 1994

Abstract

This paper presents an end-to-end solution towards authenticated positioning using only Galileo E1B signal by utilizing the Open Service Navigation Message Authentication (OSNMA). One of the primary objectives of this work is to offer a complete OSNMA-based authenticated position solution by releasing FGI-GSRx-v2.1.0 [...] Read more.

This paper presents an end-to-end solution towards authenticated positioning using only Galileo E1B signal by utilizing the Open Service Navigation Message Authentication (OSNMA). One of the primary objectives of this work is to offer a complete OSNMA-based authenticated position solution by releasing FGI-GSRx-v2.1.0 (an open-source software-defined multi-constellation GNSS receiver) update. The idea is to bridge the gap between two open-source implementations by the Finnish Geospatial Research Institute (FGI): FGI-GSRx and FGI-OSNMA (an open-source Python software package). FGI-GSRx-v2.1.0 utilizes FGI-OSNMA as an OSNMA computation engine to generate the authentication events with the information of whether a tag is valid or not. FGI-GSRx computes the position authentication at the navigation layer with the Galileo E1B satellites that are OSNMA verified and have

C / N_{0}

greater than 30 dB-Hz. OSNMA-based position authentication is shown through the findings from two real-world open sky use cases: (i) a clean nominal scenario and (ii) a spoofing scenario recorded during the Jammertest 2023 in Andøya, Norway. In the case of the spoofing scenario, the software receiver stops offering an authenticated position solution. A detailed comparison between the authenticated and non-authenticated position solutions also highlights the damage spoofing could cause to the end user in deviating the user’s position on a target spoofed location. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1598 KB

Open AccessProceeding Paper

Improving Magnetic Flux Density Fingerprint Map Matching by Mitigating AC-Induced Variability

by Peter J. Thompson, Paul D. Groves, Owen J. Griffiths, Robin J. Handley and David R. Selviah

Eng. Proc. 2025, 88(1), 59; https://doi.org/10.3390/engproc2025088059 - 20 May 2025

Viewed by 2641

Abstract

Magnetic flux density (MFD) map matching is a technique that can provide absolute position solutions by comparing a series of MFD measurements with a database. Map matching relies on the consistent measurement of the same physical phenomena during the surveying and positioning phases. [...] Read more.

Magnetic flux density (MFD) map matching is a technique that can provide absolute position solutions by comparing a series of MFD measurements with a database. Map matching relies on the consistent measurement of the same physical phenomena during the surveying and positioning phases. However, fluctuations in MFD due to alternating current (AC) electricity, influenced by dynamic power requirements, pose a challenge. This paper analyses the characteristics of the influences of AC sources on MFD measurements. It shows that employing spectral filtering can isolate magnetic perturbations from AC sources, which could be used to enhance the magnetic map matching’s resilience to this form of temporal change. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 562 KB

Open AccessProceeding Paper

Characteristics of Experimental VDE-SAT Ranging Signals and System Performance Analysis for Critical Navigation

by Øyvind Bryhn Pettersen, Jose van den IJssel and Sven-Ingve Rasmussen

Eng. Proc. 2025, 88(1), 60; https://doi.org/10.3390/engproc2025088060 - 21 May 2025

Viewed by 1567

Abstract

Traditional Global Navigation Satellite Systems (GNSSs) are subject to intentional or unintentional disturbances in the northern regions of Norway, leading to loss of critical infrastructure. The VHF Data Exchange System (VDES) has been suggested as an alternative source of positioning, navigation and timing [...] Read more.

Traditional Global Navigation Satellite Systems (GNSSs) are subject to intentional or unintentional disturbances in the northern regions of Norway, leading to loss of critical infrastructure. The VHF Data Exchange System (VDES) has been suggested as an alternative source of positioning, navigation and timing (PNT), based on statistical estimates. However, an empirical investigation into the feasibility of such a contingency-system has only recently become possible after the launch of the NorSat-TD satellite with purpose-designed VDES ranging capabilities. This paper presents an analysis of the characteristics of empirical VDE-SAT range measurements and a system-level performance analysis of a single-satellite system. In total, 1121 VDE-SAT pseudorange observations obtained from 54 satellite passes, recorded from July to October 2023, are analyzed. Residual analysis shows that these observations have a large and constant mean error of about 416 km, with a standard deviation of 335.2 m. The previously neglected atmospheric propagation effects on a VDE-SAT range measurement are shown to be significant, and the largest effect is likely to be the time-delay due to the ionosphere. The system performance analysis shows that VDE-SAT as a PNT-source has potential to be a navigation backup system, with a target metric positioning accuracy of 1000 m. This project was funded by the ESA NAVISP program. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 1745 KB

Open AccessProceeding Paper

Initial Experimentation of a Real-Time 5G mmWave Downlink Positioning Testbed

by José A. del Peral-Rosado, Ali Y. Yildirim, Auryn Soderini, Rakesh Mundlamuri, Florian Kaltenberger, Elizaveta Rastorgueva-Foi, Jukka Talvitie, Ivan Lapin and Detlef Flachs

Eng. Proc. 2025, 88(1), 61; https://doi.org/10.3390/engproc2025088061 - 29 May 2025

Cited by 2 | Viewed by 2512

Abstract

This work presents the initial experimentation of a real-time 5G mmWave downlink positioning testbed deployed at Airbus premises. This experimentation is part of a first-of-a-kind testbed for hybrid Global Navigation Satellite Systems (GNSS), fifth-generation (5G) new radio (NR) and sensor positioning, called the [...] Read more.

This work presents the initial experimentation of a real-time 5G mmWave downlink positioning testbed deployed at Airbus premises. This experimentation is part of a first-of-a-kind testbed for hybrid Global Navigation Satellite Systems (GNSS), fifth-generation (5G) new radio (NR) and sensor positioning, called the Hybrid Overlay Positioning with 5G and GNSS (HOP-5G) testbed. The mmWave 5G base station (BS) exploits the 5G standard positioning reference signal (PRS) to support positioning capabilities within the 5G NR downlink transmissions. Outdoor field results are used to characterize the received power levels and beam-based angle-of-arrival (AoA) estimation accuracy of this 5G mmWave PRS platform. The goal is to assess the suitability of this platform to enhance the positioning performance thanks to the 5G downlink mmWave transmissions. To the best of the authors’ knowledge, this paper presents the first AoA results using OpenAirInterface (OAI) PRS mmWave signal transmissions at 27 GHz for positioning. These initial field results indicate a maximum coverage of 30 m and an AoA accuracy limited by the reduced array size. The limitations and potential enhancements of this platform are provided as future recommendations. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 1408 KB

Open AccessProceeding Paper

Integrity Monitoring of GNSS Constellations with Only LEO-PNT Satellites

by Carlos Catalán Catalán, Luis García Iglesias and Andrés Juez Muñoz

Eng. Proc. 2025, 88(1), 62; https://doi.org/10.3390/engproc2025088062 - 29 May 2025

Viewed by 2218

Abstract

This paper explores the usage of LEO-PNT (Positioning, Navigation, and Timing) for providing navigation integrity to GNSS (Global Navigation Satellite System) constellations. LEO mega-constellations, which are positioned between GNSSs and users, offer closer-to-the user geometry, improving performance, reducing the time to alarm (TTA) [...] Read more.

This paper explores the usage of LEO-PNT (Positioning, Navigation, and Timing) for providing navigation integrity to GNSS (Global Navigation Satellite System) constellations. LEO mega-constellations, which are positioned between GNSSs and users, offer closer-to-the user geometry, improving performance, reducing the time to alarm (TTA) and enabling integrity monitoring without complex ground segments of any sort. The aim is to use future LEO mega-constellations as integrity monitors for a forthcoming European Global Navigation Satellite System (EGNSS) specifically focused on automotive users, which has minimal onboard satellite capabilities and no ground involvement. This plan builds on earlier studies, anticipating the performance of the upcoming LEO-PNT In-Orbit Demonstration. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 1970 KB

Open AccessProceeding Paper

Optimised Signal Selection Algorithm for Acquisition and Re-Acquisition in Multi-Constellation, Multi-Frequency GNSS Receivers

by R. Tiwari and C. Mather

Eng. Proc. 2025, 88(1), 63; https://doi.org/10.3390/engproc2025088063 - 5 Jun 2025

Viewed by 1607

Abstract

Acquiring and tracking multiple frequencies across many GNSS satellites introduces computation complexity, resulting in higher power consumption. A relatively small but optimal list of signals and satellites may result in better performance without adding additional complexity load and unnecessary power loss. This research [...] Read more.

Acquiring and tracking multiple frequencies across many GNSS satellites introduces computation complexity, resulting in higher power consumption. A relatively small but optimal list of signals and satellites may result in better performance without adding additional complexity load and unnecessary power loss. This research intended to generate an optimal list of satellites and signals and to prioritise them to be tracked by the receiver, minimising unnecessary processing. To achieve this, an optimal geometry is generated using a bootstrapping algorithm, which also introduces an innovative index to determine what to add to the satellites/signals list to prioritise acquisition and tracking. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2329 KB

Open AccessProceeding Paper

Definition of Optimal Ephemeris Parameters for LEO-PNT

by Carlos Gómez Navajas, Aitor Auz Gómez, Alejandro Muñoz Muñoz, Carlos Catalán Catalán and Andrés Juez Muñoz

Eng. Proc. 2025, 88(1), 64; https://doi.org/10.3390/engproc2025088064 - 10 Jun 2025

Cited by 1 | Viewed by 1788

Abstract

This paper addresses the selection and justification of ephemeris parameters to be broadcast in a LEO-PNT navigation message. The temporal evolution of LEO orbital elements is analyzed, proving that the GPS/GAL model needs to evolve to cope with LEO orbit dynamics and to [...] Read more.

This paper addresses the selection and justification of ephemeris parameters to be broadcast in a LEO-PNT navigation message. The temporal evolution of LEO orbital elements is analyzed, proving that the GPS/GAL model needs to evolve to cope with LEO orbit dynamics and to ensure high-accuracy ephemeris. In addition, the ephemeris fitting process is performed systematically for different sets of parameters allowing the most convenient parameter combinations to be determined. If adequate parameters are included in an ephemeris model, the fitting error tends to reduce. Beyond ephemeris parametrization, the length of the fitting interval significantly influences the achievable accuracy—for short fitting intervals of 5–10 min with an optimal set of ephemeris parameters, a SISRE at WUL in the order of 1 to 7 mm is obtained. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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8 pages, 4226 KB

Open AccessProceeding Paper

Global Ionospheric Corrections: Enhancing High-Accuracy Positioning

by Nuria Pérez, Jorge Durán, Enrique Carbonell, Ana González, David Calle and Irma Rodríguez

Eng. Proc. 2025, 88(1), 65; https://doi.org/10.3390/engproc2025088065 - 17 Jun 2025

Viewed by 1032

Abstract

Electrically charged particles present in this layer of the Earth’s atmosphere can alter radio waves, such as those from GPS, Galileo, or BeiDou, resulting in non-estimated errors with respect to the available navigation models for the end user. For most positioning algorithms based [...] Read more.

Electrically charged particles present in this layer of the Earth’s atmosphere can alter radio waves, such as those from GPS, Galileo, or BeiDou, resulting in non-estimated errors with respect to the available navigation models for the end user. For most positioning algorithms based in sequential filters, this effect is translated into a slow convergence towards a solution around the decimeter error level. If we consider that the ionosphere’s effect varies based on the user’s location and solar activity due to the atmosphere particle composition, it becomes clear that a global accurate model, valid across wide areas accounting for different seasons and timespans, is, at the very least, quite challenging. The focus of this paper is the demonstration of a global ionosphere model designed to improve the positioning accuracy of the end user through the estimation of ionospheric corrections to the broadcasted navigation message. Mathematically, this method is based on a spherical harmonic expansion model. This approach has the advantage of reducing the dependency from a highly densified station network where the ionosphere delay must be constantly estimated in dozens of locations, in favor of a simplified model that barely needs to be adjusted with a limited set of real-time data (around 40 stations). In this case, GMV’s global station network was used, which comprises geodetic-grade receivers tracking the signal in open-sky locations around the globe. The global ionospheric model is configured to process signals from GPS and Galileo constellations. To evaluate the performances of this model on the final user position estimation, several precise point positioning (PPP) solutions were computed at different locations. The results were compared with PPP solutions calculated without ionospheric corrections at the same stations. The goal of this paper is to show the significant performance improvement observed with the implementation of the global model. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 7023 KB

Open AccessProceeding Paper

Reinforcement Learning for UAV Path Planning Under Complicated Constraints with GNSS Quality Awareness

by Abdulla Alyammahi, Zhengjia Xu, Ivan Petrunin, Bo Peng and Raphael Grech

Eng. Proc. 2025, 88(1), 66; https://doi.org/10.3390/engproc2025088066 - 25 Jun 2025

Cited by 3 | Viewed by 2229

Abstract

Requirements for Unmanned Aerial Vehicle (UAV) applications in low-altitude operations are escalating, which demands resilient Position, Navigation and Timing (PNT) solutions incorporating global navigation satellite system (GNSS) services. However, UAVs often operate in stringent environments with degraded GNSS performance. Practical challenges often arise [...] Read more.

Requirements for Unmanned Aerial Vehicle (UAV) applications in low-altitude operations are escalating, which demands resilient Position, Navigation and Timing (PNT) solutions incorporating global navigation satellite system (GNSS) services. However, UAVs often operate in stringent environments with degraded GNSS performance. Practical challenges often arise from dense, dynamic, complex, and uncertain obstacles. When flying in complex environments, it is important to consider signal degradation caused by reflections (multipath) and obscuration (Non-Line of Sight (NLOS)), which can lead to positioning errors that must be minimized to ensure mission reliability. Recent works integrate GNSS reliability maps derived from pseudorange error estimations into path planning to reduce loss-of-GNSS risks with PNT degradations. To accommodate multiple constraint conditions attempting to improve flight resilience against GNSS-degraded environments, this paper proposes a reinforcement learning (RL) approach to feature GNSS signal quality awareness during path planning. The non-linear relations between GNSS signal quality in the form of dilution of precision (DoP), geographic locations, and the policy of searching sub-minima points are learned by the clipped Proximal Policy Optimization (PPO) method. Other constraints considered include static obstacle occurrence, altitude boundary, forbidden flying regions, and operational volumes. The reward and punishment functions and the training method are designed to maximize the success criteria of approaching destinations. The proposed RL approach is demonstrated using a real 3D map of Indianapolis, USA, in the Godot engine, incorporating forecasted DoP data generated by a Geospatial Augmentation system named GNSS Foresight from Spirent. Results indicate a 36% enhancement in mission success rates when GNSS performance is included in the path planning training. Additionally, the varying tensor size, representing the UAV’s DoP perception range, exhibits a positive proportion relation to a higher mission rate, despite an increment in computational complexity. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2087 KB

Open AccessProceeding Paper

Terrain-Based Parameter Optimization for Zero Velocity Update Inertial Navigation Solutions

by Taylor Knuth and Paul Groves

Eng. Proc. 2025, 88(1), 67; https://doi.org/10.3390/engproc2025088067 - 18 Jul 2025

Cited by 1 | Viewed by 3944

Abstract

This paper demonstrates the benefits of adapting Zero Velocity Update (ZVU) algorithms in foot-mounted pedestrian inertial navigation by finely tuning the algorithm to account for the type of terrain over which the pedestrian travels. Conventional ZVU algorithms for foot-mounted inertial navigation are designed [...] Read more.

This paper demonstrates the benefits of adapting Zero Velocity Update (ZVU) algorithms in foot-mounted pedestrian inertial navigation by finely tuning the algorithm to account for the type of terrain over which the pedestrian travels. Conventional ZVU algorithms for foot-mounted inertial navigation are designed for indoor use and do not account for differences from various terrains. Different terrains affect the natural pedestrian gait and how zero velocity intervals (ZVIs) are identified. By tuning the algorithm to account for accelerometer and gyroscope magnitude and walking cycle duration across four terrains (concrete, grass, pebbles and sand), the accuracy is improved up to 31.04%, dependent on the terrain, and is viable for outdoor use. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 949 KB

Open AccessProceeding Paper

Securing Global Navigation Satellite System Signals: A Software Solution for Galileo Signal Authentication

by Miguel A. Ramírez, Adrián Chamorro, Simón Cancela and David Calle

Eng. Proc. 2025, 88(1), 68; https://doi.org/10.3390/engproc2025088068 - 30 Jul 2025

Viewed by 537

Abstract

The Galileo program is adding a layer of security through the Galileo Assisted Commercial Authentication Service (ACAS). This service complements Galileo Open Service Navigation Message Authentication (OSNMA) by introducing signal authentication through commercial service signals. In this framework, the ACAS employs a unique [...] Read more.

The Galileo program is adding a layer of security through the Galileo Assisted Commercial Authentication Service (ACAS). This service complements Galileo Open Service Navigation Message Authentication (OSNMA) by introducing signal authentication through commercial service signals. In this framework, the ACAS employs a unique approach to protect pseudoranges by incorporating authentication features. These features are implemented at the spreading-code level, utilizing spreading-code encryption on the signal to perform spreading-code authentication. The service is based on the re-encryption and publication of short-duration spreading sequences from an existing encrypted signal, such as the Galileo E6C signal. The re-encryption process enables the receiver to autonomously retrieve the required sequences without continuous communication with an external server. This paper details a commercial software solution implementing the ACAS service, designed for integration across a wide array of applications. A comprehensive description of the ACAS software solution and testing in nominal scenarios will be presented, leading to conclusions that assess the software’s performance, capabilities in real scenarios, and suggestions for further improvements. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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9 pages, 3679 KB

Open AccessProceeding Paper

Enhancing GNSS Situational Awareness by Monitoring the New Galileo Services

by Toni Hammarberg, Fabricio S. Prol and Mohammad Zahidul H. Bhuiyan

Eng. Proc. 2025, 88(1), 69; https://doi.org/10.3390/engproc2025088069 - 19 Aug 2025

Cited by 2 | Viewed by 1208

Abstract

Global Navigation Satellite Systems (GNSSs) have become a critical service in modern society, and this has increased the need for GNSS situational awareness. On top of this, the GNSS field is rapidly changing. Increased signal interference has been observed in the last few [...] Read more.

Global Navigation Satellite Systems (GNSSs) have become a critical service in modern society, and this has increased the need for GNSS situational awareness. On top of this, the GNSS field is rapidly changing. Increased signal interference has been observed in the last few decades, requiring more prominent GNSS services, in addition to flexibility and adaptability from GNSS monitoring systems. With the emergence of new Galileo features, such as Open Service Navigation Message Authentication (OSNMA) and the High Accuracy Service (HAS), monitoring systems have the opportunity to leverage these new services to enhance GNSS situational awareness. The Finnish Geospatial Research Institute (FGI) has developed an open GNSS situational awareness service called GNSS-Finland, which monitors signal quality, detects potential interference, and informs users of the expected level of performance of different services around 47 stations in the Finnish Continuously Operating Reference Station (CORS) network (FinnRef). Recently GNSS-Finland’s capabilities have been extended to monitor and leverage OSNMA and the HAS around FinnRef stations. Due to the novelty of both OSNMA and the HAS, custom software solutions are needed to integrate these services into GNSS-Finland. We give an overview of GNSS-Finland and its flexible architecture, present the integration of the new Galileo services into GNSS-Finland, and finally discuss how these new services can be leveraged from a monitoring system point of view. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 816 KB

Open AccessProceeding Paper

Mitigating GPS Spoofing Threats with Honeywell GPS-Aided Inertial Systems

by Matej Kucera, Radek Reznicek, Radek Baranek, Pavel Ptacek, Daniel Bertrand and Karl Keyzer

Eng. Proc. 2025, 88(1), 70; https://doi.org/10.3390/engproc2025088070 - 20 Aug 2025

Viewed by 4903

Abstract

GNSS-Inertial integration brings great potential to detect and mitigate the effect of erroneous (spoofed) GNSS data. When a trajectory of an airplane diverges from (or is inconsistent with) inertial data, the integrated system may detect this erroneous GNSS trajectory and may be able [...] Read more.

GNSS-Inertial integration brings great potential to detect and mitigate the effect of erroneous (spoofed) GNSS data. When a trajectory of an airplane diverges from (or is inconsistent with) inertial data, the integrated system may detect this erroneous GNSS trajectory and may be able to maintain navigation integrity by rejecting this data. A GNSS-Aided Inertial System can provide both self-contained detection of a GNSS spoofing event as well as mitigation, where mitigation is hard to achieve globally with other commercial aviation systems relying on good ground system coverage. This paper provides an overview of the newly developed Inertial Spoofing Monitor for aviation grade navigation systems, which was designed to detect multiple simultaneous erroneous (spoofed) satellite measurements. The Inertial Spoofing Monitor was then thoroughly tested, and simulations were performed to evaluate and demonstrate the detection, mitigation, and recovery capability of the spoofing monitor. The performance validation followed the process prescribed by Appendix Q of the RTCA DO-384 MOPS (Minimum Operation Performance Standard). The results show great detection, mitigation, and recovery performance of the developed Inertial Spoofing Monitor, but also indicate constraints regarding the assumed sensor error model. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 4876 KB

Open AccessProceeding Paper

Permanent Train-Side GNSS Multipath Characterization Considering Time-Correlation for Safe Railway Localization

by Ana Kliman, Anja Grosch and Omar Garcia Crespillo

Eng. Proc. 2025, 88(1), 71; https://doi.org/10.3390/engproc2025088071 - 20 Aug 2025

Viewed by 1341

Abstract

Railway transportation systems have high accuracy and high integrity demands for safe localization. In the future, railway signaling is expected to rely on onboard sensors like Global Navigation Satellite Systems (GNSSs) in order to reduce installation and maintenance costs. GNSS position determination can, [...] Read more.

Railway transportation systems have high accuracy and high integrity demands for safe localization. In the future, railway signaling is expected to rely on onboard sensors like Global Navigation Satellite Systems (GNSSs) in order to reduce installation and maintenance costs. GNSS position determination can, however, be highly degraded because of the presence of multipath on the train and railway environment. This paper tackles the characterization of multipath in code measurements caused exclusively by the antenna installation and derives a conservative error model of the antenna-installation-induced multipath and noise. First, we isolate multipath and noise from other GNSS errors using the Code-Minus-Carrier method. Second, an overbounding error model is derived. The limitation of modeling with restricted set of real data typically found in practice is discussed and we review methods that ensure the independence of samples. A new approach that creates separate data sets is ultimately proposed to derive an overbounding sigma. The presented methodology is supported by real measurements collected in an open-sky railway scenario. The derived models can be used as a reference nominal error models to build the null hypothesis of fault detection algorithms that detects the presence of excessive multipath in dynamic scenarios or as a part of a total error budget consideration. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2564 KB

Open AccessProceeding Paper

Multipath Characterization of GNSS Ground Stations Using RINEX Observations and Machine Learning

by Gerardo Allende-Alba, Stefano Caizzone and Ernest Ofosu Addo

Eng. Proc. 2025, 88(1), 72; https://doi.org/10.3390/engproc2025088072 - 22 Aug 2025

Viewed by 1746

Abstract

Multipath is one of the most challenging factors to model and/or characterize in the GNSS observation error budget. In the case of ground stations, code phase static multipath is typically the largest contributor of local observation errors. Current approaches for multipath characterization include [...] Read more.

Multipath is one of the most challenging factors to model and/or characterize in the GNSS observation error budget. In the case of ground stations, code phase static multipath is typically the largest contributor of local observation errors. Current approaches for multipath characterization include the analysis of code-minus-carrier (CMC) observables and the exploitation of multipath repeatability. This contribution presents an alternative strategy for multipath detection and characterization based on unsupervised and self-supervised machine learning methods. The proposed strategy makes use of observations in the Receiver Independent Exchange Format (RINEX), typically generated by GNSS receivers in ground stations, for model training and testing, without requiring the availability of labeled data. To assess the performance of the proposed strategy (data-based), a comparison with a model-based methodology for multipath error prediction using a digital twin model is carried out. Results from a test case using data from a monitoring station of the International GNSS Service (IGS) show a point of consistency between the two approaches. The proposed methodology is applicable for a similar characterization in any GNSS ground station. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2685 KB

Open AccessProceeding Paper

Performance Monitoring for Galileo High Accuracy Service and Reliable Galileo Service Operations

by Ganesh Lalgudi Gopalakrishnan, Antonio Salonico, Javier De Blas, Valerio Carandente, Pedro Pintor and Chris Nordmann

Eng. Proc. 2025, 88(1), 73; https://doi.org/10.3390/engproc2025088073 - 25 Aug 2025

Viewed by 2393

Abstract

In this paper, we present the performance reporting of one of the selected Galileo services, namely the HAS. Specifically, we present the evolution of the monitored Galileo HAS correction quality and availability as well as the HAS-derived user positioning accuracy at selected Galileo [...] Read more.

In this paper, we present the performance reporting of one of the selected Galileo services, namely the HAS. Specifically, we present the evolution of the monitored Galileo HAS correction quality and availability as well as the HAS-derived user positioning accuracy at selected Galileo Sensor Stations (GSSs). Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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12 pages, 749 KB

Open AccessProceeding Paper

Positioning of a Lunar Lander Using a Dedicated Lunar Communication and Navigation System Assuming Realistic ODTS Performances

by Yoann Audet, Floor T. Melman, Dimitrios V. Psychas, Richard D. Swinden and Javier Ventura-Traveset

Eng. Proc. 2025, 88(1), 74; https://doi.org/10.3390/engproc2025088074 - 27 Aug 2025

Viewed by 1847

Abstract

With the renewed interest in the Moon, manifested by the growing number of planned missions for the past decade, space agencies are investing in reliable and dedicated lunar communication and navigation systems and services, such as the Moonlight programme of the European Space [...] Read more.

With the renewed interest in the Moon, manifested by the growing number of planned missions for the past decade, space agencies are investing in reliable and dedicated lunar communication and navigation systems and services, such as the Moonlight programme of the European Space Agency (ESA), to provide support to all types of lunar users (i.e., surface users, landers and orbiters). In the context of lunar human and robotic exploration, one of the critical phases will be the landing of spacecraft on lunar soil. This type of operation is far from trivial, as shown by the recent crashes such as the one of the Luna25 lander from the Russian Space Agency. A reliable method to position a lander during its descent could be provided by a dedicated lunar navigation system. This paper will focus on what the achievable positioning accuracy is for a lander landing on the Moon’s South Pole using dedicated satellite-based navigation services such as Moonlight. It will be shown that using the LCNS constellation and the altimeter can achieve a sub 50 m accuracy with a 99% confidence interval. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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11 pages, 2041 KB

Open AccessProceeding Paper

Enhancing GNSS Robustness in Automotive Applications with Supercorrelation: Experimental Results in Urban Scenarios

by Javier Gonzalo Garcia, Johannes Rossouw van der Merwe, Hery Mwenegoha, Paulo Esteves, Samir Benmendil, Eugene Coetzee, James Ellis, Henry Eriksson-Martin, Rose Grey, Chris Higgins, Dana Jamal, Suraksha Kokradi, Ongun Kurt, Ramsey Faragher and Mark Crockett

Eng. Proc. 2025, 88(1), 75; https://doi.org/10.3390/engproc2025088075 - 10 Sep 2025

Viewed by 1471

Abstract

Mitigating multipath interference is one of the biggest challenges in radio positioning. The Supercorrelation™ technology developed via Focal Point Positioning (FPP) suppresses multipath interference by performing long coherent integration while undergoing complex motion to isolate the Line-Of-Sight (LOS) signals from the unwanted multipath [...] Read more.

Mitigating multipath interference is one of the biggest challenges in radio positioning. The Supercorrelation™ technology developed via Focal Point Positioning (FPP) suppresses multipath interference by performing long coherent integration while undergoing complex motion to isolate the Line-Of-Sight (LOS) signals from the unwanted multipath interference.This article presents live results with a Supercorrelating Global Navigation Satellite System (S-GNSS) Software-Defined Radio (SDR), demonstrating significantly suppressed multipath to regain position accuracy. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 3328 KB

Open AccessProceeding Paper

Jamming and Spoofing Detection and Classification Performance Under Hostile GNSS Environments

by Ali Broumandan, Ali Pirsiavash, Isabelle Tremblay and Sandy Kennedy

Eng. Proc. 2025, 88(1), 76; https://doi.org/10.3390/engproc2025088076 - 12 Dec 2025

Viewed by 1725

Abstract

Civilian Global Navigation Satellite Systems (GNSS) play a crucial role in critical infrastructure and safety-critical applications, where their low signal power and open descriptions make them vulnerable to threats such as jamming and spoofing. To address these major challenges and growing concerns, NovAtel’s [...] Read more.

Civilian Global Navigation Satellite Systems (GNSS) play a crucial role in critical infrastructure and safety-critical applications, where their low signal power and open descriptions make them vulnerable to threats such as jamming and spoofing. To address these major challenges and growing concerns, NovAtel’s OEM7 receivers are equipped with an advanced GNSS Resilience and Integrity Technology (GRIT) to identify and respond to GNSS threats effectively. This includes Interference Toolkit (ITK), Spoofing Detection Toolkit (SK) and Robust Dual-Antenna Receiver (RoDAR), which employ a range of countermeasures, from jamming detection and characterization to spoofing detection and mitigation, ensuring solution integrity and reliability. The newly developed Galileo Open Service Navigation Message Authentication (OSNMA) module also offers an additional layer of protection by checking for the authenticity of the navigation message for Galileo E1 signals. This paper evaluates the performance of NovAtel’s OEM7 receivers in detecting and mitigating jamming and spoofing using real event data. Effective jamming detection was achieved through spectrum monitoring across all GNSS bands. The effectiveness of GRIT’s anti-jamming and anti-spoofing technologies was demonstrated in advanced test cases. OSNMA results are discussed, highlighting its role as a complementary protection layer for enhanced GNSS security. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 984 KB

Open AccessProceeding Paper

NLOS Signal Detection from Early–Late Prompt Correlators Using Convolutional LSTM Network

by Zhengjia Xu, Ivan Petrunin, Antonios Tsourdos, Pekka Peltola, Smita Tiwari, Martin Bransby and Nicolas Giron

Eng. Proc. 2025, 88(1), 77; https://doi.org/10.3390/engproc2025088077 - 19 Dec 2025

Viewed by 817

Abstract

The emerging development of Global Navigation Satellite System (GNSS) software receivers has opened new opportunities in diverse operations. However, non-line-of-sight (NLOS) concatenated signal reception is one prevalent deterioration factor causing positioning errors in urban scenarios. To enhance integrity and reliability through receiver autonomous [...] Read more.

The emerging development of Global Navigation Satellite System (GNSS) software receivers has opened new opportunities in diverse operations. However, non-line-of-sight (NLOS) concatenated signal reception is one prevalent deterioration factor causing positioning errors in urban scenarios. To enhance integrity and reliability through receiver autonomous integrity monitoring (RAIM) techniques in urban environments, distinguishing between line-of-sight (LOS) and NLOS signals facilitates the exclusion of NLOS channels: this is challenging due to uncertain signal reflections/refractions from diverse obstruction conditions in the built environment. Moreover, NLOS features show similarity to multipath effects like scattering and diffraction which causes difficulty in identifying the NLOS type. Recent work exploited NLOS detections with multi-correlator outputs using neural networks that outperform using signal strength techniques for NLOS detection. This paper proposes a neural network approach designed to recognise and learn spatial features among early, late, and prompt correlator outputs, differentiating between correlations, and also by memorising temporal features to acquire propagation information. Specifically, the spatial features of correlator IQ streams are derived from convolutional layers incorporated with concatenations, to formulate associate models like early-minus-late discrimination. A Recurrent Neural Network (RNN), i.e., long short-term memory (LSTM), is integrated to obtain comprehensive temporal features; hereby, a softmax classifier is appended in the last layer to distinguish between NLOS and LOS signals. By simulating synthetic datasets generated by a Spirent simulator and captured by a software-defined radio (SDR), the correlator outputs are acquired during the scalar tracking stage. The product of the proposed network demonstrates high performance in terms of accuracy, time consumption and sensitivity, affirming the efficiency of utilising early-stage correlations for NLOS detection. Moreover, an impact analysis of varying the sliding window length on NLOS discrimination underscores the need to fine-tune the parameter, as well as balancing accuracy, operation complexity and sensitivity. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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8 pages, 2778 KB

Open AccessProceeding Paper

A Model for Data–Pilot Biases in Presence of Satellite and Receiver Imperfections

by Christoph Enneking, Steffen Thölert, Peter Steigenberger and Oliver Montenbruck

Eng. Proc. 2025, 88(1), 78; https://doi.org/10.3390/engproc2025088078 - 22 Dec 2025

Viewed by 503

Abstract

The data and pilot channel of the Global Positioning System (GPS) L5 signal and other modernized signals of the global navigation satellite system (GNSS) are subject to an intra-signal bias. This tracking-mode-dependent bias causes problems for the harmonized usage of receiver network data, [...] Read more.

The data and pilot channel of the Global Positioning System (GPS) L5 signal and other modernized signals of the global navigation satellite system (GNSS) are subject to an intra-signal bias. This tracking-mode-dependent bias causes problems for the harmonized usage of receiver network data, such as from the International GNSS Service (IGS). While previous studies have focused on exhaustive numeric analysis of the data–pilot bias, this work takes a closer look at the possible causes at satellite and receiver level. Our findings indicate that the data–pilot bias on GPS L5 can be well explained with a small set of parameters that are all related to the payload. These parameters include the digital distortion of the data and pilot component, plus a relative shift of the two components. Furthermore, our numerical results indicate that the according inter-signal corrections (ISCs) may need more frequent updates. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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10 pages, 2505 KB

Open AccessProceeding Paper

Flight Test Performance Assessment of a Machine-Learning Software-Enhanced Inertial Navigation System

by Matthew Starkey, Carl Sequeira, Conrad Rider, Gabriel Furse and Dylan Palmer-Jorge

Eng. Proc. 2025, 88(1), 79; https://doi.org/10.3390/engproc2025088079 - 6 Jan 2026

Viewed by 884

Abstract

In this paper, Flare Bright presents flight test results gathered using a ~2m fixed wingspan drone to demonstrate the capability that has been achieved using an Inertial Navigation System (INS) augmented by Machine Learning tuned software. INSs, using Inertial Measurement Units (IMUs), are [...] Read more.

In this paper, Flare Bright presents flight test results gathered using a ~2m fixed wingspan drone to demonstrate the capability that has been achieved using an Inertial Navigation System (INS) augmented by Machine Learning tuned software. INSs, using Inertial Measurement Units (IMUs), are invaluable for position estimation in GNSS-compromised environments as no external information is required. However, with no absolute measurement of a vehicle’s position or attitude, INSs suffer from significant drift over time. The results from a robust flight test programme, over multiple vehicles, terrains and flight paths, show how Flare Bright combined a low cost and low SWaP (space, weight and power) IMU, with their patent-pending software-only techniques, to boost INS performance to the degree of besting a ‘tactical grade’ IMU in ~20 min. These results credibly demonstrate the value of Flare Bright’s solution as an effective, low-cost and low-weight INS for extended flight operations of small uncrewed aerial systems in GNSS-compromised environments, with performance comparable to heavier, more expensive high-end IMUs. Full article

(This article belongs to the Proceedings of European Navigation Conference 2024)

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