Multichannel interferometric SAR phase unwrapping using extended Kalman Smoother

2013 ◽  
Vol 5 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Davide Chirico ◽  
Gilda Schirinzi
Keyword(s):  
Phase Unwrapping ◽  
Sensor Data ◽  
Bayesian Estimator ◽  
Bayesian Approaches ◽  
Strong Discontinuities ◽  
Absolute Phase ◽  
Multi Sensor Data Fusion ◽  
Digital Elevation ◽  
Elevation Model ◽  
Interferometric Sar

Phase unwrapping (PU) is one of the key processing steps in reconstructing the digital elevation model (DEM) of a scene from interferometric synthetic aperture radar (InSAR) data. The PU problem entails the estimation of an absolute phase from observation of its noisy principal (wrapped) values. Recently, PU approaches based on Kalman filtering have proved their efficacy in tackling the PU problem even when strong discontinuities of the height profile and noisy data are involved. This paper presents a novel multichannel InSAR PU algorithm using several interferometric SAR images based on the extended Kalman filter. The proposed technique exploits the capability of the Kalman algorithm to simultaneously perform noise filtering, PU, and multi-sensor data fusion. The proposed method, even being a Bayesian estimator, optimally fuses height information coming from an additional maximum likelihood estimator (MLE) combining the benefits of both the Bayesian and the non-Bayesian approaches. The performance of the proposed algorithm has been tested on simulated interferometric images proving the effectiveness of the proposed method.

Analysis and Evaluation of InSAR Phase Unwrapping Approaches

2011 ◽  
Vol 301-303 ◽  
pp. 1029-1035
Author(s):  
Shu Bi Zhang ◽  
Tuo Fu
Keyword(s):  
Network Flow ◽  
Minimum Cost ◽  
Phase Unwrapping ◽  
Sar Interferometry ◽  
Analysis And Evaluation ◽  
Digital Elevation ◽  
Cut Method ◽  
Minimum Cost Network Flow ◽  
Elevation Model ◽  
Interferometric Sar

In recent years SAR interferometry has become a widely used technique for measuring altitude and displacement of the surface of the earth. Phase unwrapping of the interferometric SAR is a very important step to obtain an accurate DEM(Digital Elevation Model)[1,2,3],and phase unwrapping is not only crucial in InSAR but also a major source in InSAR errors. Therefore, with GAMMA software, VC++ and MATLAB coding implementing six kinds of phase unwrapping approaches ,this paper presents the best method for different situations through two sets of experimental results used for analysing and comparing run time and precision. In the plain and alpine area, the best phase unwrapping methods are separately Goldstein branch-cut method and Minimum Cost Network Flow method.

scholarly journals Evaluation of Atmospheric Effects on Interferograms Using DEM Errors of Fixed Ground Points

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2336 ◽  
Author(s):  
Takashi Nonaka ◽  
Tomohito Asaka ◽  
Keishi Iwashita
Keyword(s):  
Phase Noise ◽  
Atmospheric Effects ◽  
Sar Images ◽  
Single Pass ◽  
Digital Elevation ◽  
Total Phase ◽  
Disaster Monitoring ◽  
The Difference ◽  
Elevation Model ◽  
Interferometric Sar

High-resolution synthetic aperture radar (SAR) data are widely used for disaster monitoring. To extract damaged areas automatically, it is essential to understand the relationships among the sensor specifications, acquisition conditions, and land cover. Our previous studies developed a method for estimating the phase noise of interferograms using several pairs of TerraSAR-X series (TerraSAR-X and TanDEM-X) datasets. Atmospheric disturbance data are also necessary to interpret the interferograms; therefore, the purpose of this study is to estimate the atmospheric effects by focusing on the difference in digital elevation model (DEM) errors between repeat-pass (two interferometric SAR images acquired at different times) and single-pass (two interferometric SAR images acquired simultaneously) interferometry. Single-pass DEM errors are reduced due to the lack of temporal decorrelation and atmospheric disturbances. At a study site in the city of Tsukuba, a quantitative analysis of DEM errors at fixed ground objects shows that the atmospheric effects are estimated to contribute 75% to 80% of the total phase noise in interferograms.

scholarly journals ICESAT VALIDATION OF TANDEM-X I-DEMS OVER THE UK

2016 ◽  
Vol XLI-B4 ◽  
pp. 129-136 ◽  
Author(s):  
L. Feng ◽  
J.-P. Muller
Keyword(s):  
Slope Aspect ◽  
Surface Slope ◽  
Grid Spacing ◽  
Digital Elevation ◽  
X Band ◽  
Elevation Data ◽  
Vertical Accuracy ◽  
Elevation Model ◽  
The Uk ◽  
Interferometric Sar

From the latest TanDEM-X mission (bistatic X-Band interferometric SAR), globally consistent Digital Elevation Model (DEM) will be available from 2017, but their accuracy has not yet been fully characterised. This paper presents the methods and implementation of statistical procedures for the validation of the vertical accuracy of TanDEM-X iDEMs at grid-spacing of approximately 12.5 m, 30 m and 90 m based on processed ICESat data over the UK in order to assess their potential extrapolation across the globe. The accuracy of the TanDEM-X iDEM in UK was obtained as follows: against ICESat GLA14 elevation data, TanDEM-X iDEM has −0.028±3.654 m over England and Wales and 0.316 ± 5.286 m over Scotland for 12 m, −0.073 ± 6.575 m for 30 m, and 0.0225 ± 9.251 m at 90 m. Moreover, 90 % of all results at the three resolutions of TanDEM-X iDEM data (with a linear error at 90 % confidence level) are below 16.2 m. These validation results also indicate that derivative topographic parameters (slope, aspect and relief) have a strong effect on the vertical accuracy of the TanDEM-X iDEMs. In high-relief and large slope terrain, large errors and data voids are frequent, and their location is strongly influenced by topography, whilst in the low- to medium-relief and low slope sites, errors are smaller. ICESat derived elevations are heavily influenced by surface slope within the 70 m footprint as well as there being slope dependent errors in the TanDEM-X iDEMs.

scholarly journals SAR Interferometric Baseline Refinement Based on Flat-Earth Phase without a Ground Control Point

2020 ◽  
Vol 12 (2) ◽  
pp. 233 ◽  
Author(s):  
Bing Xu ◽  
Zhiwei Li ◽  
Yan Zhu ◽  
Jiancun Shi ◽  
Guangcai Feng
Keyword(s):  
Control Point ◽  
Least Square ◽  
Synthetic Aperture ◽  
Ground Control ◽  
Ground Control Point ◽  
Refinement Method ◽  
Digital Elevation ◽  
Elevation Model ◽  
Interferometric Sar ◽  
Baseline Estimation

Interferometric baseline estimation is a key procedure of interferometric synthetic aperture radar (SAR) data processing. The error of the interferometric baseline affects not only the removal of the flat-earth phase, but also the transformation coefficient between the topographic phase and elevation, which will affect the topographic phase removal for differential interferometric SAR (D-InSAR) and the accuracy of the final generated digital elevation model (DEM) product for interferometric synthetic aperture (InSAR). To obtain a highly accurate interferometric baseline, this paper firstly investigates the geometry of InSAR imaging and establishes a rigorous relationship between the interferometric baseline and the flat-earth phase. Then, a baseline refinement method without a ground control point (GCP) is proposed, where a relevant theoretical model and resolving method are developed. Synthetic and real SAR datasets are used in the experiments, and a comparison with the conventional least-square (LS) baseline refinement method is made. The results demonstrate that the proposed method exhibits an obvious improvement over the conventional LS method, with percentages of up to 51.5% in the cross-track direction. Therefore, the proposed method is effective and advantageous.

scholarly journals Elevation changes (1949–1995) of Black Rapids Glacier, Alaska, derived from a multi-baseline InSAR DEM and historical maps

2010 ◽  
Vol 56 (198) ◽  
pp. 625-634 ◽  
Author(s):  
Dan H. Shugar ◽  
Bernhard T. Rabus ◽  
John J. Clague
Keyword(s):  
Phase Unwrapping ◽  
Historical Maps ◽  
Center Line ◽  
Alaska Range ◽  
Ground Survey ◽  
Digital Elevation ◽  
Maximum Elevation ◽  
Elevation Changes ◽  
Black Rapids Glacier ◽  
Elevation Model

AbstractWe have constructed a new digital elevation model (DEM) of the 1995 surface of Black Rapids Glacier, a surge-type glacier in the central Alaska Range, using ERS-1/-2 repeat-pass interferometry. We isolated the topographic phase from three interferograms with contrasting perpendicular baselines. Numerous phase-unwrapping errors caused by areas of poor coherence were corrected in all three interferograms, using a novel, iterative, semi-automated approach that capitalizes on the multi-baseline nature of the dataset. Comparison of our DEM with a 1949 US Geological Survey DEM and with 1973–95 ground survey data shows the gradual return of Black Rapids Glacier to a pre-surge hypsometry following a surge in 1936/37. Maximum elevation changes along the glacier center line in the ablation and accumulation areas are, respectively, −249 and +63 m (−5.4 and +1.4 m a−1). Maximum elevation changes of survey points at nearby locations are −4.9 m a−1 (1975–84) and +0.5 m a−1 (1975–85). Center-line thickening of +62 m between 1949 and 1995 (+1.4 m a−1), just above the Loket tributary in the upper part of the ablation zone, indicates dynamic thickening following the 1936/37 surge.

scholarly journals Deceptive Targets Generation Simulation Against Multichannel SAR

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 597
Author(s):  
Penghui Ji ◽  
Shiqi Xing ◽  
Dahai Dai ◽  
Bo Pang
Keyword(s):  
Synthetic Aperture ◽  
Minimum Condition ◽  
Complex Coefficient ◽  
Sar Images ◽  
Digital Elevation ◽  
Deceptive Jamming ◽  
Elevation Model ◽  
Interferometric Sar ◽  
General Architecture ◽  
Ground Moving Target Indication

Traditional synthetic aperture radar (SAR) deceptive jamming can effectively generate deceptive scenes or false targets in SAR images. However, these false targets or scenes can be easily distinguished or eliminated by the multichannel SAR system. To interfere with the multichannel SAR, we first analyzed the results of SAR deceptive jamming generated by one transponder and two transponders against three-channel SAR- ground moving target indication (GMTI). Then, we propose a new deceptive jamming method against three-channel SAR-GMTI by using three synergetic transponders. By modulating each transponder with a complex coefficient, three synergetic transponders can generate false moving targets with the controllable radial velocity and located azimuth position in three-channel SAR-GMTI. Besides, in this paper, we also introduce an algorithm to deploy three transponders reasonably by utilizing the minimum condition number. In the end, a general architecture of multiple transponders deceiving multichannel SAR is given. The proposed method can not only generate deceptive false targets against multichannel SAR-GMTI, but also guide the production of a deceptive digital elevation model (DEM) against multichannel interferometric SAR (InSAR). Simulations verify the effectiveness of the proposed method.

scholarly journals InSAR Baseline Estimation for Gaofen-3 Real-Time DEM Generation

2018 ◽  
Author(s):  
Huan Lu ◽  
Zhiyong Suo ◽  
Zhenfang Li ◽  
Jinwei Xie ◽  
Qingjun Zhang
Keyword(s):  
Real Time ◽  
Estimation Method ◽  
Shuttle Radar Topography Mission ◽  
The Real ◽  
Digital Elevation ◽  
Orbit Fitting ◽  
Elevation Model ◽  
Interferometric Sar ◽  
Baseline Estimation ◽  
Baseline Error

For Interferometry Synthetic Aperture Radar (InSAR), the normal baseline is one of the main factors that affect the accuracy of the ground elevation. For Gaofen-3 (GF-3) InSAR processing, the poor accuracy of the real-time orbit determination resulting in a large baseline error, leads to the modulation error in azimuth and the slope error in range for timely Digital Elevation Model (DEM) generation. In order to address this problem, a baseline estimation method based on external DEM is proposed in this paper. Firstly, according to the characteristic of the real-time orbit of GF-3 images, orbit fitting is executed to remove the non-linear error factor. Secondly, the height errors are obtained in slant-range plane between Shuttle Radar Topography Mission (SRTM) DEM and the GF-3 generated DEM after orbit fitting. At the same time, the height errors are used to estimate the baseline error which has a linear variation. In this way, the orbit error can be calibrated by the estimated baseline error. Finally, DEM generation is performed by using the modified baseline and orbit. This procedure is implemented iteratively to achieve a higher accuracy DEM. Based on the results of GF-3 interferometric SAR data for Hebei, the effectiveness of the proposed algorithm is verified and the accuracy of GF-3 real-time DEM products can be improved extensively.

Evaluation of digital elevation model generated by an airborne interferometric SAR (Pi-SAR2)

2014 ◽  
Author(s):  
Tatsuharu Kobayashi ◽  
Toshihiko Umehara ◽  
Jyunpei Uemoto ◽  
Makoto Satake ◽  
Shoichiro Kojima ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
Digital Elevation ◽  
Elevation Model ◽  
Interferometric Sar
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