Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique

In Sentinel-1 TOPS mode, the antenna sweeps in the azimuth direction for the purpose of illuminating the targets with the entire azimuth antenna pattern (AAP). This azimuth sweeping introduces an extra high-frequency Doppler term into the impulse response function (IRF), which poses a more strict co...

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Main Authors: Yuxiao Qin, Daniele Perissin, Jing Bai
Format: Article
Language:English
Published: MDPI AG 2018-09-01
Series:Remote Sensing
Subjects:
Online Access:http://www.mdpi.com/2072-4292/10/9/1405
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spelling doaj-d12f59a8b0b74d5eb04d0c37e151a41c2020-11-25T02:29:16ZengMDPI AGRemote Sensing2072-42922018-09-01109140510.3390/rs10091405rs10091405Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation TechniqueYuxiao Qin0Daniele Perissin1Jing Bai2Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USALyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USASchool of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, ChinaIn Sentinel-1 TOPS mode, the antenna sweeps in the azimuth direction for the purpose of illuminating the targets with the entire azimuth antenna pattern (AAP). This azimuth sweeping introduces an extra high-frequency Doppler term into the impulse response function (IRF), which poses a more strict coregistration accuracy for the interferometric purpose. A 1/1000 pixel coregistration accuracy is required for the interferometric phase error to be negligible, and the enhanced spectral diversity (ESD) method is applied for achieving such accuracy. However, since ESD derives miscoregistration from cross-interferometric phase, and phase is always wrapped to [ − π , π ) , an initial coregistration method with enough accuracy is required to resolve the phase ambiguity in ESD. The mainstream for initial coregistration that meets this requirement is the geometrical approach, which accuracy mainly depends on the accuracy of orbits. In this article, the authors propose to investigate the feasibility of using the conventional coregistration approach, namely the cross-correlation-and-rigid-transformation, as the initial coregistration method. The aim is to quantify the coregistration accuracy for cross-correlation-and-rigid-transformation using the Cramér-Rao lower bound (CRLB) and determine whether this method could eventually help to resolve the phase ambiguities of ESD. In addition, we studied the feasibility and robustness of the cross-correlation plus ESD under different conditions. For validation, we checked whether the cross-correlation plus ESD approach could reach the same coregistration accuracy as geometrical plus ESD approach. In general, for large areas with enough coherence and little topography variance, the cross-correlation method could be used as an alternative to the geometrical approach. The interferogram from the two different approaches (with ESD applied afterward) shows a negligible difference under such circumstances.http://www.mdpi.com/2072-4292/10/9/1405TOPScoregistrationcross correlationrigid transformationCramér-Rao lower bound
collection DOAJ
language English
format Article
sources DOAJ
author Yuxiao Qin
Daniele Perissin
Jing Bai
spellingShingle Yuxiao Qin
Daniele Perissin
Jing Bai
Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
Remote Sensing
TOPS
coregistration
cross correlation
rigid transformation
Cramér-Rao lower bound
author_facet Yuxiao Qin
Daniele Perissin
Jing Bai
author_sort Yuxiao Qin
title Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
title_short Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
title_full Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
title_fullStr Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
title_full_unstemmed Investigations on the Coregistration of Sentinel-1 TOPS with the Conventional Cross-Correlation Technique
title_sort investigations on the coregistration of sentinel-1 tops with the conventional cross-correlation technique
publisher MDPI AG
series Remote Sensing
issn 2072-4292
publishDate 2018-09-01
description In Sentinel-1 TOPS mode, the antenna sweeps in the azimuth direction for the purpose of illuminating the targets with the entire azimuth antenna pattern (AAP). This azimuth sweeping introduces an extra high-frequency Doppler term into the impulse response function (IRF), which poses a more strict coregistration accuracy for the interferometric purpose. A 1/1000 pixel coregistration accuracy is required for the interferometric phase error to be negligible, and the enhanced spectral diversity (ESD) method is applied for achieving such accuracy. However, since ESD derives miscoregistration from cross-interferometric phase, and phase is always wrapped to [ − π , π ) , an initial coregistration method with enough accuracy is required to resolve the phase ambiguity in ESD. The mainstream for initial coregistration that meets this requirement is the geometrical approach, which accuracy mainly depends on the accuracy of orbits. In this article, the authors propose to investigate the feasibility of using the conventional coregistration approach, namely the cross-correlation-and-rigid-transformation, as the initial coregistration method. The aim is to quantify the coregistration accuracy for cross-correlation-and-rigid-transformation using the Cramér-Rao lower bound (CRLB) and determine whether this method could eventually help to resolve the phase ambiguities of ESD. In addition, we studied the feasibility and robustness of the cross-correlation plus ESD under different conditions. For validation, we checked whether the cross-correlation plus ESD approach could reach the same coregistration accuracy as geometrical plus ESD approach. In general, for large areas with enough coherence and little topography variance, the cross-correlation method could be used as an alternative to the geometrical approach. The interferogram from the two different approaches (with ESD applied afterward) shows a negligible difference under such circumstances.
topic TOPS
coregistration
cross correlation
rigid transformation
Cramér-Rao lower bound
url http://www.mdpi.com/2072-4292/10/9/1405
work_keys_str_mv AT yuxiaoqin investigationsonthecoregistrationofsentinel1topswiththeconventionalcrosscorrelationtechnique
AT danieleperissin investigationsonthecoregistrationofsentinel1topswiththeconventionalcrosscorrelationtechnique
AT jingbai investigationsonthecoregistrationofsentinel1topswiththeconventionalcrosscorrelationtechnique
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