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Special Issue "Global Positioning Systems (GPS) and Applications"

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A special issue of Remote Sensing (ISSN 2072-4292).

Deadline for manuscript submissions: closed (31 December 2010)

Special Issue Editor

Guest Editor
Prof. Dr. Chris Rizos

School of Surveying & Spatial Information Systems, the University of New South Wales, Sydney, Australia
Website | E-Mail
Interests: geodesy; GPS/GNSS technology and applications; navigation; precise positioning algorithms; continuously operating GPS/GNSS reference station infrastructure

Keywords

  • GPS/GNSS technology
  • applications
  • navigation
  • precise positioning

Published Papers (5 papers)

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Research

Open AccessArticle Regional Mapping of the Geoid Using GNSS (GPS) Measurements and an Artificial Neural Network
Remote Sens. 2011, 3(4), 668-683; doi:10.3390/rs3040668
Received: 22 December 2010 / Revised: 15 January 2011 / Accepted: 24 February 2011 / Published: 30 March 2011
Cited by 5 | PDF Full-text (1950 KB) | HTML Full-text | XML Full-text
Abstract
The determination of the orthometric height from geometric leveling has practical difficulties that, despite a number of scientific and technological advances, passed a century without substantial modifications or advances. Currently, the Global Navigation Satellite System (GNSS) has been used with reasonable success for
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The determination of the orthometric height from geometric leveling has practical difficulties that, despite a number of scientific and technological advances, passed a century without substantial modifications or advances. Currently, the Global Navigation Satellite System (GNSS) has been used with reasonable success for orthometric height determination. With a sufficient number of benchmarks with known horizontal and vertical coordinates, it is often possible to adjust using the least squares method mathematical expressions that allow interpolation of geoid heights. The objective of this study is to present an alternative method to interpolate geoid heights based on the technique of Artificial Neural Networks (ANNs). The study area is the Brazilian state of São Paulo, and for training the ANN the authors have used geoid height information from the EGM08 gravity model with a grid spacing of 10 minutes of arc. The efficiency of the model was tested at 157 points with known geoid heights distributed across the study area. The results were also compared with the Brazilian Geoid Model (MAPGEO2004). Based on those 157 benchmarks it was possible to verify that the model generated by ANNs provided a mean absolute error of 0.24 m in obtaining a geoid height value. Statistical tests have shown that there was no difference between the means from known geoid heights and geoid heights provided by the neural model for a significance level of 5%. It was also found that ANNs provided an improvement of 2.7 times in geoid height estimates when compared with the MAPGEO2004 geoid model. Full article
(This article belongs to the Special Issue Global Positioning Systems (GPS) and Applications)
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Open AccessArticle GPS Bias Correction and Habitat Selection by Mountain Goats
Remote Sens. 2011, 3(3), 435-459; doi:10.3390/rs3030435
Received: 23 December 2010 / Revised: 24 February 2011 / Accepted: 24 February 2011 / Published: 28 February 2011
Cited by 6 | PDF Full-text (934 KB) | HTML Full-text | XML Full-text
Abstract
In Washington State, USA, mountain goats (Oreamnos americanus) have experienced a long-term population decline. To assist management, we created annual and seasonal (summer and winter) habitat models based on 2 years of data collected from 38 GPS-collared (GPS plus collar v6,
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In Washington State, USA, mountain goats (Oreamnos americanus) have experienced a long-term population decline. To assist management, we created annual and seasonal (summer and winter) habitat models based on 2 years of data collected from 38 GPS-collared (GPS plus collar v6, Vectronic-Aerospace GmbH, Berlin, Germany) mountain goats in the western Cascades. To address GPS bias of position acquisition, we evaluated habitat and physiographic effects on GPS collar performance at 543 sites in the Cascades. In the western Cascades, total vegetation cover and the quadratic mean diameter of trees were shown to effect GPS performance. In the eastern Cascades, aspect and total vegetation cover were found to influence GPS performance. To evaluate the influence of bias correction on the analysis of habitat selection, we created resource selection functions with and without bias correction for mountain goats in the western Cascades. We examined how well the resultant habitat models performed with reserved data (25% of fixes from 38 study animals) and with data from 9 other GPS-collared mountain goats that were both temporally and spatially independent. The statistical properties of our GPS bias correction model were similar to those previously reported explaining between 20 and 30% of the variation, however, application of bias correction improved the accuracy of the mountain goat habitat model by only 1–2% on average and did not alter parameter estimates in a meaningful, or consistent manner. Despite statistical limitations, our habitat models, most notably during the winter, provided the widest extent and most detailed models of the distribution of mountain goat habitat in the Cascades yet developed. Full article
(This article belongs to the Special Issue Global Positioning Systems (GPS) and Applications)
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Open AccessArticle Inferring Snow Water Equivalent for a Snow-Covered Ground Reflector Using GPS Multipath Signals
Remote Sens. 2010, 2(10), 2426-2441; doi:10.3390/rs2102426
Received: 9 September 2010 / Revised: 13 October 2010 / Accepted: 18 October 2010 / Published: 20 October 2010
Cited by 18 | PDF Full-text (590 KB) | HTML Full-text | XML Full-text
Abstract
A nonlinear least squares fitting algorithm is used to estimate both snow depth and snow density for a snow-layer above a flat ground reflector. The product of these two quantities, snow depth and density, provides an estimate of the snow water equivalent. The
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A nonlinear least squares fitting algorithm is used to estimate both snow depth and snow density for a snow-layer above a flat ground reflector. The product of these two quantities, snow depth and density, provides an estimate of the snow water equivalent. The input to this algorithm is a simple ray model that includes a speculary reflected signal along with a direct signal. These signals are transmitted from the global positioning system satellites at 1.57542 GHz with right-hand circularly polarization. The elevation angles of interest at the GPS receiving antenna are between 5° and 30°. The results from this nonlinear algorithm show potential for inferring snow water equivalent using GPS multipath signals. Full article
(This article belongs to the Special Issue Global Positioning Systems (GPS) and Applications)
Open AccessArticle Towards Sea Ice Remote Sensing with Space Detected GPS Signals: Demonstration of Technical Feasibility and Initial Consistency Check Using Low Resolution Sea Ice Information
Remote Sens. 2010, 2(8), 2017-2039; doi:10.3390/rs2082017
Received: 30 June 2010 / Revised: 11 August 2010 / Accepted: 11 August 2010 / Published: 25 August 2010
Cited by 21 | PDF Full-text (1167 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents two space detected Global Positioning System (GPS)signals reflected off sea ice and compares the returned power profiles with independent estimates of ice concentration provided by the Advanced Microwave Scanning Radiometer (AMSR-E) and sea ice charts from the National Ice Center.
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This paper presents two space detected Global Positioning System (GPS)signals reflected off sea ice and compares the returned power profiles with independent estimates of ice concentration provided by the Advanced Microwave Scanning Radiometer (AMSR-E) and sea ice charts from the National Ice Center. The results of the analysis show significantly different signals received for each of the GPS reflections. For the first collection,comparisons with ice concentration estimates from AMSR-E and the National Ice Centers reveal a very strong GPS signal return off high concentration sea ice. The second GPS data collection occurs over a region of changing sea ice concentration, and the GPS signal level responds at roughly the same point that the AMSR-E data and National Ice Center charts indicate a change in ice concentration. However, the very strong signal of the first GPS collection is not consistent in magnitude with similar ice concentrations during the secondGPS data collection. This demonstration shows the potential and the difficulties of this new technique as a valuable low-cost compliment to existing sea ice monitoring instruments. Additionally, a general method for calculating the location of the specular reflection point on the Earth’s surface and the received Doppler frequencies and code phase delays is presented as part of an on-board open-loop signal tracking technique. Full article
(This article belongs to the Special Issue Global Positioning Systems (GPS) and Applications)
Open AccessArticle Global Evaluation of Radiosonde Water Vapor Systematic Biases using GPS Radio Occultation from COSMIC and ECMWF Analysis
Remote Sens. 2010, 2(5), 1320-1330; doi:10.3390/rs2051320
Received: 24 February 2010 / Revised: 30 April 2010 / Accepted: 5 May 2010 / Published: 7 May 2010
Cited by 32 | PDF Full-text (845 KB) | HTML Full-text | XML Full-text
Abstract
In this study, we compare specific humidity profiles derived from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) from August to November 2006 with those from different types of radiosonde and from ECMWF global analysis. Comparisons show that COSMIC
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In this study, we compare specific humidity profiles derived from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) from August to November 2006 with those from different types of radiosonde and from ECMWF global analysis. Comparisons show that COSMIC specific humidity data agree well with ECMWF analysis over different regions of the world for both day and night times. On the contrary, evaluation against COSMIC specific humidity shows a distinct dry bias of Shang-E radiosonde (China) and an obvious wet bias of VIZ-type (USA). No obvious specific humidity biases are found for MRZ (Russia) and MEISEI (Japan) radiosondes. These results demonstrate the usefulness of COSMIC water vapor for quantifying the dry/wet biases among different sensor types. Full article
(This article belongs to the Special Issue Global Positioning Systems (GPS) and Applications)
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