scholarly journals ScanSAR Interferometry of the Gaofen-3 Satellite with Unsynchronized Repeat-Pass Images

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4689 ◽  
Author(s):  
Sun ◽  
Yu ◽  
Dong ◽  
Luo
Keyword(s):  
Synthetic Aperture Radar ◽  
Phase Error ◽  
Control Point ◽  
Closed Form Solution ◽  
Form Solution ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Image Pair ◽  
Phase Compensation ◽  
Aperture Radar

Gaofen-3 is a Chinese remote sensing satellite with multiple working modes, among which the scanning synthetic aperture radar (ScanSAR) mode is used for wide-swath imaging. synthetic aperture radar (SAR) interferometry in the ScanSAR mode provides the most rapid way to obtain a global digital elevation model (DEM), which can also be realized by Gaofen-3. Gaofen-3 ScanSAR interferometry works in the repeat-pass mode, and image pair non-synchronizations can influence its performance. Non-synchronizations can include differences of burst central times, satellite velocities, and burst durations. Therefore, it is necessary to analyze their influences and improve the interferometric coherence. Meanwhile, interferometric phase compensation and rapid DEM geolocation also need to be considered in interferometric processing. In this paper, interferometric coherence was analyzed in detail, followed by an iterative filtering method, which helped to improve the interferometric performance. Further, a phase compensation method for Gaofen-3 was proposed to compensate for the phase error caused by the unsynchronized azimuth time offset of image pair, and a closed-form solution of DEM geolocation with ground control point (GCP) information was derived. Application of our methods to a pair of Gaofen-3 interferometric images showed that these methods were able to process the images with good accuracy and efficiency. Notably, these analysis and processing methods can also be applied to other SAR satellites in the ScanSAR mode to obtain DEMs with high quality.

scholarly journals Refocusing Moving Ship Targets in SAR Images Based on Fast Minimum Entropy Phase Compensation

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1154 ◽  
Author(s):  
Xiangli Huang ◽  
Kefeng Ji ◽  
Xiangguang Leng ◽  
Ganggang Dong ◽  
Xiangwei Xing
Keyword(s):  
Synthetic Aperture Radar ◽  
Phase Error ◽  
Synthetic Aperture ◽  
Sar Image ◽  
Minimum Entropy ◽  
Sar Images ◽  
Phase Compensation ◽  
Translation Motion ◽  
Airborne Sar ◽  
Aperture Radar

Moving ship targets appear blurred and defocused in synthetic aperture radar (SAR) images due to the translation motion during the coherent processing. Motion compensation is required for refocusing moving ship targets in SAR scenes. A novel refocusing method for moving ship is developed in this paper. The method is exploiting inverse synthetic aperture radar (ISAR) technique to refocus the ship target in SAR image. Generally, most cases of refocusing are for raw echo data, not for SAR image. Taking into account the advantages of processing in SAR image, the processing data are SAR image rather than raw echo data in this paper. The ISAR processing is based on fast minimum entropy phase compensation method, an iterative approach to obtain the phase error. The proposed method has been tested using Spaceborne TerraSAR-X, Gaofeng-3 images and airborne SAR images of maritime targets.

Method of phase error analysis and compensation for terahertz inverse synthetic aperture radar

2013 ◽  
Vol 25 (6) ◽  
pp. 1469-1474
Author(s):  
刘磊 Liu Lei ◽  
周峰 Zhou Feng ◽  
陶明亮 Tao Mingliang ◽  
张子敬 Zhang Zijing
Keyword(s):  
Error Analysis ◽  
Synthetic Aperture Radar ◽  
Phase Error ◽  
Synthetic Aperture ◽  
Inverse Synthetic Aperture Radar ◽  
Aperture Radar

scholarly journals Forest mapping and monitoring with interferometric synthetic aperture radar (InSAR)

2001 ◽  
Vol 25 (2) ◽  
pp. 159-177 ◽  
Author(s):  
H. Balzter
Keyword(s):  
Synthetic Aperture Radar ◽  
Electromagnetic Waves ◽  
Forest Canopy ◽  
Thermal State ◽  
Time Lag ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Dimensional Structure ◽  
Forest Mapping ◽  
Aperture Radar

A synthetic aperture radar (SAR) is an active sensor transmitting pulses of polarized electromagnetic waves and receiving the backscattered radiation. SAR sensors at different wavelengths and with different polarimetric capabilities are being used in remote sensing of the earth. The value of an analysis of backscattered energy alone is limited due to ambiguities in the possible ecological factor configurations causing the signal. From two SAR images taken from similar viewing positions with a short time-lag, interference between the two waves can be observed. By subtracting the two phases of the signals, it is feasible to eliminate the random contribution of the scatterers to the phase. The interferometric correlation and the interferometric phase contain additional information on the three-dimensional structure of the scattering elements in the imaged area. A brief review of SAR sensors is given, followed by an outline of the physical foundations of SAR interferometry and the practical data-processing steps involved. An overview of applications of InSAR to forest mapping and monitoring is given, covering tree-bole volume and biomass, forest types and land cover, fire scars, forest thermal state and forest canopy height.

Transient active deformation in Tainan tableland using persistent scatterers SAR interferometry

2013 ◽  
Vol 184 (4-5) ◽  
pp. 441-450 ◽  
Author(s):  
Yu-Yia Wu ◽  
Jyr-Ching Hu ◽  
Geng-Pei Lin ◽  
Chung-Pai Chang ◽  
Hsin Tung ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Surface Deformation ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Uplift Rate ◽  
Active Deformation ◽  
Radar Images ◽  
Persistent Scatterers ◽  
Area North ◽  
Aperture Radar

Abstract Persistent scatterers SAR interferometry (PS-InSAR) was employed to monitor surface deformation in and around the Tainan tableland using 20 advanced synthetic aperture radar (ASAR) images from the ENVISAT satellite taken during the period from 2005 May 19 to 2008 September 25. In our study, we have found that the uplift rate of the northern Tainan tableland is faster than the southern tableland. The slant range displacement (SRD) rate for the area north along the precise leveling array is about 5 to 10 mm/yr with respect to the western edge of the Tainan tableland, whereas the SRD rate for the area south of the leveling array is about 1 to 5 mm/yr. In addition, the uplifted area extends eastward to the Tawan lowland with a maximum SRD rate of nearly 10 mm/yr, which is almost the same as the rate of the Tainan tableland. Results of this study differ from those suggested in previous researches that employed ERS-1/2 radar images taken from 1996 to 1999 and the differential interferometry synthetic aperture radar (D-InSAR) technique. Our findings indicated that the Tawan lowland no longer subsides with respect to the western edge of the Tainan tableland, and that both northern and southern areas are experiencing uplift.

scholarly journals Synthetic Aperture Radar (SAR) Interferometry for Assessing Wenchuan Earthquake (2008) Deforestation in the Sichuan Giant Panda Site

2014 ◽  
Vol 6 (7) ◽  
pp. 6283-6299 ◽  
Author(s):  
Fulong Chen ◽  
Huadong Guo ◽  
Natarajan Ishwaran ◽  
Wei Zhou ◽  
Ruixia Yang ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Wenchuan Earthquake ◽  
Giant Panda ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Aperture Radar

scholarly journals Fusion of SAR Interferometry and Polarimetry Methods for Landslide Reactivation Study, the Bureya River (Russia) Event Case Study

2021 ◽  
Vol 13 (24) ◽  
pp. 5136
Author(s):  
Valery Bondur ◽  
Tumen Chimitdorzhiev ◽  
Aleksey Dmitriev ◽  
Pavel Dagurov
Keyword(s):  
Synthetic Aperture Radar ◽  
Radar Data ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Line Of Sight ◽  
Scattering Mechanisms ◽  
Radar Images ◽  
Landslide Reactivation ◽  
Sbas Insar ◽  
Aperture Radar

In this paper, we demonstrate the estimation capabilities of landslide reactivation based on various SAR (Synthetic Aperture Radar) methods: Cloude-Pottier decomposition of Sentinel-1 dual polarimetry data, MT-InSAR (Multi-temporal Interferometric Synthetic Aperture Radar) techniques, and cloud computing of backscattering time series. The object of the study is the landslide in the east of Russia that took place on 11 December 2018 on the Bureya River. H-α-A polarimetric decomposition of C-band radar images not detected significant transformations of scattering mechanisms for the surface of the rupture, whereas L-band radar data show changes in scattering mechanisms before and after the main landslide. The assessment of ground displacements along the surface of the rupture in the 2019–2021 snowless periods was carried out using MT-InSAR methods. These displacements were 40 mm/year along the line of sight. The SBAS-InSAR results have allowed us to reveal displacements of great area in 2020 and 2021 snowless periods that were 30–40 mm/year along the line-of-sight. In general, the results obtained by MT-InSAR methods showed, on the one hand, the continuation of displacements along the surface of the rupture and on the other hand, some stabilization of the rate of landslide processes.

Glacier displacement on Comfortlessbreen, Svalbard, using 2-pass differential SAR interferometry (DInSAR) with a digital elevation model

Polar Record ◽  
2011 ◽  
Vol 48 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Nora Jennifer Schneevoigt ◽  
Monica Sund ◽  
Wiley Bogren ◽  
Andreas Kääb ◽  
Dan Johan Weydahl
Keyword(s):  
Synthetic Aperture Radar ◽  
Digital Elevation Model ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Synthetic Aperture Radar Interferometry ◽  
Glacier Terminus ◽  
Digital Elevation ◽  
Reference Images ◽  
Elevation Model ◽  
Aperture Radar

ABSTRACTDifferential synthetic aperture radar interferometry (DInSAR) exploits the coherence between the phases of two or more satellite synthetic aperture radar (SAR) scenes taken from the same orbit to separate the phase contributions from topography and movement by subtracting either phase. Hence pure terrain displacement can be derived without residual height information in it, but only the component of movement in line-of-sight direction is represented in a differential interferogram. Comfortlessbreen, a recently surging glacier, flows predominantly in this direction with respect to the European Remote Sensing satellites ERS-1 and ERS-2. Four C-band SAR scenes from spring 1996 were selected because of the high coherence between the respective pairs of the 1-day repeat-pass tandem mission of the ERS sensors. 2-pass DInSAR is performed in combination with a SPOT5 (Satéllite pour l'Observation de la Terre 5) SPIRIT (SPOT5 stereoscopic survey of Polar Ice: Reference Images and Topography) digital elevation model (DEM) from 2007. The different processing steps and intermediate image products, including unwrapping and generation of displacement maps, are detailed in order to convey the DInSAR processing chain to the beginner in the field of interferometry. Maximum horizontal displacements of 18 to 20 cm d−1 in ground range direction can be detected at the glacier terminus, while a few centimetres per day characterised most of the middle and upper portions of Comfortlessbreen in spring 1996.

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