GECORIS: An Open-Source Toolbox for Analyzing Time Series of Corner Reflectors in InSAR Geodesy

Czikhardt, Richard; Marel, H. van der; Papčo, Juraj

doi:10.3390/rs13050926

Cited by 9 publications

(16 citation statements)

References 44 publications

(94 reference statements)

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“…SAR time series analysis of the transponders is performed using the open-source toolbox GECORIS [11]. For the position of each transponder in each of the SLCs, an image patch of 10×10 resolution cells is selected and oversampled by a factor 32 in the frequency domain by zero-padding.…”

Section: Sentinel-1 Time Series Analysismentioning

confidence: 99%

On the Efficacy of Compact Radar Transponders for InSAR Geodesy: Results of Multiyear Field Tests

Czikhardt

Marel²,

Papčo

et al. 2022

IEEE Trans. Geosci. Remote Sensing

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Compact and low-cost radar transponders are an attractive alternative to corner reflectors (CR) for SAR interferometric (InSAR) deformation monitoring, datum connection, and geodetic data integration. Recently, such transponders have become commercially available for C-band sensors, which poses relevant questions on their characteristics in terms of radiometric, geometric, and phase stability. Especially for extended time series and for high-precision geodetic applications, the impact of secular or seasonal effects, such as variations in temperature and humidity, has yet to be proven. Here we address these challenges using a multitude of short baseline experiments with four transponders and six corner reflectors deployed at test sites in the Netherlands and Slovakia. Combined together, we analyzed 980 transponder measurements in Sentinel-1 time series to a maximum extent of 21 months. We find an average Radar Cross Section (RCS) of over 42 dBm 2 within a range of up to 15 degrees of elevation misalignment, which is comparable to a triangular trihedral corner reflector with a leg length of 2.0 m. Its RCS shows temporal variations of 0.3-0.7 dBm 2 (standard deviation) which is partially correlated with surface temperature changes. The precision of the InSAR phase double-differences over short baselines between a transponder and a stable reference corner reflectors is found to be 0.5-1.2 mm (one sigma). We observe a correlation with surface temperature, leading to seasonal variations of up to ±3 mm, which should be modeled and corrected for in high precision InSAR applications. For precise SAR positioning, we observe antenna-specific constant internal electronic delays of 1.2-2.1 m in slant-range, i.e., within the range resolution of the Sentinel-1 IW product, with a temporal variability of less than 20 cm. Comparing similar transponders from the same series, we observe distinct differences in performance. Our main conclusion is that these characteristics are favorable for a wide range of geodetic applications. For particular demanding applications, individual calibration of single devices is strongly recommended.

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Section: Sentinel-1 Time Series Analysismentioning

confidence: 99%

On the Efficacy of Compact Radar Transponders for InSAR Geodesy: Results of Multiyear Field Tests

Czikhardt

Marel²,

Papčo

et al. 2022

IEEE Trans. Geosci. Remote Sensing

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“…The toolbox is modular and standalone that provides functionality in two layers: analysis of SAR time series without tasks that are computationally demanding and analysis of the full area that includes the analysis of the InSAR time series. The toolbox demonstrates uniqueness in its application and the geodetic community [75]. The S1TBX (Sentinel-1) toolbox which is a part of the SNAP (Sentinel application platform) software has been developed for displaying, reading and writing data from different remote sensing satellites like the ENVISAT, ERS, Sentinel-1.…”

Section: E Discussionmentioning

confidence: 99%

Curved Synthetic Aperture Radar for Near-Field Terahertz Imaging

Gezimati

Singh

2023

IEEE Photonics J.

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High resolution imaging technique will play an essential role in the future smart imaging applications to provide potential solutions for accurate detection, monitoring and classification of the target. The potential of synthetic aperture radar (SAR) systems to acquire high resolution images has opened new frontiers and led to its exploration in new applications. The conventional microwave radar imaging suffers limited range resolution in the sub-millimeter wave range and optical imaging methods are constrained by the diffraction limit. In the terahertz (THz) regime of the spectrum, the SAR systems could be operated in all the weather, all the time and are capable of penetrating through clouds, smoke, dust etc. to achieve high resolution images beyond the diffraction limit. The curved SAR presents a SAR system created by circularly encircling the target scene. The Circular SAR and Spiral SAR which are based on a circular and cylindrical spiral scanning trajectory, respectively are the scanning methods used for curved SAR. In this paper, we have explored a new toolbox that enables the rapid development of near-field THz-SAR imaging systems and generation of large near-field THz imaging scenarios with the goal to support and facilitate data driven research such as deep learning in the THz community through synthetically generated SAR images as well as its potential for THz based high resolution and 2D/3D near-field imaging application. Initially, the potential advantages of THz-SAR over Microwave SAR and optical imaging methods are presented. Further, a frequency modulated continuous wave (FMCW) radar testbed is simulated in multi-input multi-output (MIMO) configuration for the target frequency band. Moreover, the circular and cylindrical SAR scanning methods are explored for near-field imaging of point targets to obtain 2D and 3D THz-SAR images, respectively. Also, the radar images are reconstructed using the Back Propagation and Polar Formatting Algorithms, focusing on short range applications like indoor environments. Finally, the SAR performance evaluation metrics are reported and a roadmap for future work is presented.

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“…The known position of the effective phase centre allows to determine the SAR positioning errors and opens possibilities for geodetic InSAR co-location. The exploitation of several CRs covering the whole critical area can create a subsidence monitoring network which can provide reliable displacement time series over the critical subsidence zones, strengthen the natural PS estimation network, improve the positioning precision of the nearby natural PS and provide an absolute geodetic reference for the InSAR displacement estimates (Czikhardt et al, 2021;. The particular benefit of using artificial reflectors is the precise knowledge of their effective phase centre, allowing the direct colocation with other geodetic measurements in the observation space with local ties known with accuracy better than the measurement noise of the observation techniques at hand.…”

Section: Insar Analysismentioning

confidence: 99%

Multi-sensor and multi-temporal approach in monitoring of deformation zone with permanent monitoring solution and management of environmental changes: A case study of Solotvyno salt mine, Ukraine

et al. 2023

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Salt deposits were a rich source of mineral resources in the past, and some are still mined today. However, salt mines, especially abandoned ones, pose a threat to populated areas, infrastructure and the natural environment. Solotvyno (Ukraine) is one of the most significantly affected areas, with a deformation zone where significant year-on-year subsidences occur. Mining activities have caused a disturbance of the balance in the mountain massif, and as a consequence, the mountains are being reshaped, and the land cover is deformed. Deformation zone of the historical salt mine Solotvyno (Ukraine), Tyachiv district of Zakarpattia region is situated on the right bank of the Tisza river in the border area with Romania in Central Europe. This paper deals with the multi-sensor monitoring of the active deformation zone over the Solotvyno salt mine using satellite radar data (Sentinel-1), optical satellite imagery (Pleiades, SPOT) and in-situ UAV photogrammetry. Since the area represents a significant geohazard from a hydrogeological (Tisza River) and civil security standpoints (infrastructure of the inhabited regions), the design of a high-precision monitoring system to monitor and evaluate current environmental changes is proposed. Multi-temporal InSAR analysis exposed steeper subsidence tendencies of >−2 cm in the central part of the monitored area. Optical satellite and UAV images confirmed the increase in water surface in sinkhole areas up to 28,500 m2 and proved the emergence of new sinkholes in the central part of the Solotvyno mine. The aim of this study is to describe the post-collapse deformation processes by Pleiades and SPOT multi-spectral sensors and Sentinel-1 satellite SAR sensors since the 2010 collapse in order to describe the trends of deformation due to undermining and propose a high-precision permanent monitoring system based on satellite radar interferometry (InSAR).

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GECORIS: An Open-Source Toolbox for Analyzing Time Series of Corner Reflectors in InSAR Geodesy

Cited by 9 publications

References 44 publications

On the Efficacy of Compact Radar Transponders for InSAR Geodesy: Results of Multiyear Field Tests

On the Efficacy of Compact Radar Transponders for InSAR Geodesy: Results of Multiyear Field Tests

Curved Synthetic Aperture Radar for Near-Field Terahertz Imaging

Multi-sensor and multi-temporal approach in monitoring of deformation zone with permanent monitoring solution and management of environmental changes: A case study of Solotvyno salt mine, Ukraine

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