Search Results (8)

Research on extreme environmental exploration using unmanned robots has recently attracted significant attention. In particular, unmanned robot exploration in vast areas such as Antarctica requires a system capable of remotely monitoring and controlling multiple robots. This paper proposes an integrated control system designed to monitor, control, and assign exploration tasks to multiple robots operating in extreme environments. This system utilizes GPS-based collaboration to support specific tasks, such as crevasse exploration and automatic battery charging, in Antarctic target areas. The system’s user interface (UI) is designed for efficiency and integrates elements such as remote control and mission execution commands tailored to the Antarctic environment. The proposed system was implemented using three robot platforms, and through performance evaluation tests in Antarctica, it achieved a cumulative driving distance of over 500 km and over 200 h of operation for over a month. The successful execution of simultaneous crevasse exploration by three robots highlights the system’s capability for coordinated multi-robot operations in extreme environments. Full article

Exploring crevasses in extreme environments such as Antarctica is highly dangerous yet essential for ensuring safe movement. Recently, robotic systems have been investigated as a means to conduct exploration in such regions. Unlike conventional settings, these environments require integrated capabilities, including mobility in harsh terrain and the ability to operate reliably at extremely low temperatures. In this paper, we propose KAREX (Korea Antarctic Robot EXplorer), a robotic exploration system designed to investigate crevasses and support research activities in extreme environments. The robot is engineered for cold resistance with thermal insulation that enables low-power temperature maintenance, and it supports multiple swappable batteries for extended-range operation. The proposed system was tested at Jang Bogo Station in Antarctica to verify its performance and applicability in real-world extreme conditions. Full article

This paper introduces a UWB-based human-following system for polar-exploration robots, integrating obstacle and crevasse avoidance functions to enhance the safety and efficiency of explorers in extreme environments. The proposed system determines the relative position of the explorer using UWB anchors and tags. It also utilizes real-time local obstacle mapping and path-planning algorithms to find safe paths that avoid collisions with obstacles. Simulation and real-world experiments confirm that the proposed system operates effectively in polar environments, reducing the operational burden on explorers and increasing mission success rates. Full article

Coal mining causes overlying rocks to collapse and be destroyed. Overburdened crevasses provide a channel for gas discharge, which is a serious safety hazard. To study the evolution characteristics and migration pattern of overburdened fissures during the initial mining period, the 24207 working face of the Shaquan mine was used as a research object. Through similar physical simulation tests, a mechanical model of the mining structure during the initial mining period was constructed to explore the factors influencing the movement pattern of the overburden strata during the initial mining period. The research results show that the evolution of mining-induced fractures in the overburdened strata in the initial mining period mainly experience the slow and rapid rising stages of the fracture dimension, while the stable mining period is in the stable development stage of the fracture dimension. The research results will help supplement and improve the theory of gas disaster prevention and comprehensive resource utilization in the initial mining stage under the mining conditions of high gas and low permeability coal seam group, achieve the goal of “coal and gas co-mining”, and ensure the safe and efficient production of mines. Full article

Big Harris Creek, North Carolina, possesses a geomorphic history and alluvial stratigraphic record similar to many drainages in southern Appalachian Piedmont. An approximately 1 km reach of Upper Stick Elliott Creek, a tributary to Big Harris Creek, was used herein to (1) explore the use of chemostratigraphic methods to define and correlate late Holocene alluvial deposits along this relatively uncontaminated rural stream containing legacy sediments (historic, anthropogenically derived deposits), and (2) interpret depositional floodplain processes within small (<10 km²), headwater drainages. The lithofacies within four floodplain sections were described in channel banks and sampled at about 5 cm intervals. The 128 collected samples were then analyzed for grain size and the concentration of 22 elements using X-ray fluorescence. Well-defined chemostratigraphic units (facies) were defined on the basis of a multi-elemental fingerprint using a principal component analysis (PCA) and verified using discriminant analysis (DA). Chemostratigraphic units did not reflect grain size at a site (by design) but marginally correlated to lithofacies defined by field descriptions. Of significant importance, chemostratigraphic units could be quantitatively correlated between the four stratigraphic sections at a much higher spatial resolution (~5 cm) than could be performed using other sedimentologic parameters alone. In combination, the lithostratigraphic and chemostratigraphic architecture of the floodplain is consistent with a previously proposed sequence of deposition for the legacy deposits in which extensive land-use change associated with the onset of cotton farming in the 1860s led to upstream incision and gully formation and downstream deposition on the floodplain surface. Deposition appears to have progressed downvalley as incision deepened, probably in the form of crevasse splay deposits or proximal sandsheets that were occasionally interbedded with vertically accreted sediments. The results indicate that chemostratigraphy represents a highly useful approach to the assessment of floodplain depositional processes over (at least) relatively small temporal and spatial scales, even in areas with minimal sediment contamination. Full article

Crevasses are formed by glacier movement and the stresses within glacier ice. Knowledge of the crevasses’ distribution is critical for understanding the glacier and ice shelf stability. In this study, we propose an automated crevasse extraction framework based on Sentinel-1 SAR imagery and an improved U-Net network. The spatial distribution of crevasses on Antarctic ice shelves in 2020 was mapped with a spatial resolution of ~40 m, and the characteristics of crevasses on the Nickerson Ice Shelf, Jelbart Ice Shelf, Amery Ice Shelf, Thwaites Glacier, and Shackleton Ice Shelf were analyzed. The results indicated the extraction accuracy of our method was 84.2% and the F1 score was 72.5%. Compared with previous published studies, the identification of the crevasse areas had good visual consistency. However, in some scenes, the recall rate was relatively lower due to the quality of the SAR image, terrain surrounding the crevasses, and observation geometry. The crevasses on different ice shelves had different characteristics in terms of length, density, type, and spatial pattern, implying the different stress structures of ice shelves. The Thwaites Glacier and the Nickerson Ice Shelf in the West Antarctica Ice Sheet (WAIS) had shorter ice crevasses, whereas the lengths of ice crevasses on the Jelbart Ice Shelf and the Amery Ice Shelf in the East Antarctica Ice Sheet (EAIS) were relatively long. Nevertheless, there are more closely spaced crevasses on the ice shelf in WAIS compared to that in the EAIS. For the distribution of crevasse types, the Nickerson Ice Shelf and the Shackleton Ice Shelf had various forms of crevasses. There were mainly transverse crevasses developed on the Jelbart Ice Shelf and the Amery Ice Shelf. This study provides a helpful reference and guidance for automated crevasse extraction. The method proposed by this study manifests great application potential and the efficacy of producing a time-series crevasse data set with higher spatial resolution and larger coverage. In the future, more Sentinel-1 SAR imagery will be applied and the effect of temporal and spatial variations in crevasses on the stability of ice shelves will be investigated, which will contribute to project the ice shelf stability and explore the sea level rise implications of recent and future cryosphere changes. Full article

Ice thickness and bed topography of fast-flowing outlet glaciers are large sources of uncertainty for the current ice sheet models used to predict future contributions to sea-level rise. Due to a lack of coverage and difficulty in sounding and imaging with ice-penetrating radars, these regions remain poorly constrained in models. Increases in off-nadir scattering due to the highly crevassed surfaces, volumetric scattering (due to debris and/or pockets of liquid water), and signal attenuation (due to warmer ice near the bottom) are all impediments in detecting bed-echoes. A set of high-frequency (HF)/very high-frequency (VHF) radars operating at 14 MHz and 30–35 MHz were developed at the University of Kansas to sound temperate ice and outlet glaciers. We have deployed these radars on a small unmanned aircraft system (UAS) and a DHC-6 Twin Otter. For both installations, the system utilized a dipole antenna oriented in the cross-track direction, providing some performance advantages over other temperate ice sounders operating at lower frequencies. In this paper, we describe the platform-sensor systems, field operations, data-processing techniques, and preliminary results. We also compare our results with data from other ice-sounding radars that operate at frequencies both above (Center for Remote Sensing of Ice Sheets (CReSIS) Multichannel Coherent Depth Sounder (MCoRDS)) and below (Jet Propulsion Laboratory (JPL) Warm Ice Sounding Explorer (WISE)) our HF/VHF system. During field campaigns, both unmanned and manned platforms flew closely spaced parallel and repeat flight lines. We examine these data sets to determine image coherency between flight lines and discuss the feasibility of forming 2D synthetic apertures by using such a mission approach. Full article

Mendocino Channel, a deep-water sinuous channel located along the base of Gorda Escarpment, was for the first time completely mapped with a multibeam echosounder. This study uses newly acquired multibeam bathymetry and backscatter, together with supporting multichannel seismic and sediment core data to quantitatively describe the morphometry of the entire Mendocino Channel and to explore the age and possible causes that may have contributed to the formation and maintenance of the channel. The first 42 km of the channel is a linear reach followed for the next 83.8 km by a sinuous reach. The sinuous reach has a sinuosity index of 1.66 before it changes back to a linear reach for the next 22.2 km. A second sinuous reach is 40.2 km long and the two reaches are separated by a crevasse splay and a large landslide that deflected the channel northwest towards Gorda Basin. Both sinuous reaches have oxbow bends, cut-off meanders, interior and exterior terraces and extensive levee systems. The lower sinuous reach becomes more linear for the next 22.2 km before the channel relief falls below the resolution of the data. Levees suddenly decrease in height above the channel floor mid-way along the lower linear reach close to where the channel makes a 90° turn to the southwest. The entire channel floor is smooth at the resolution of the data and only two large mounds and one large sediment pile were found on the channel floor. The bathymetry and acoustic backscatter, together with previously collected seismic data and box and piston cores provide details to suggest Mendocino Channel may be no older than early Quaternary. A combination of significant and numerous earthquakes and wave-loading resuspension by storms are the most likely processes that generated turbidity currents that have formed and modified Mendocino Channel. Full article