A new Doppler frequency anomaly algorithm for surface current measurement with SAR

作     者：Lihua WANG Yanghua GAO Peng LU Li FAN Yunxuan ZHOU Lihua WANG;Yanghua GAO;Peng LU;Li FAN;Yunxuan ZHOU

作者机构：Department of Geography and Spatial Information TechniquesCenter for Land and Marine Spatial Utilization and Governance ResearchNingbo UniversityNingbo 315211China Institute of East China SeaNingbo UniversityNingbo 315211China Chongqing Institute of Meteorological SciencesChongqing 401147China College of Geo-Exploration Science and TechnologyJilin UniversityChangchun 130026China State Key Laboratory of Estuarine and Coastal ResearchEast China Normal UniversityShanghai 200062China 

出 版 物：《Journal of Oceanology and Limnology》 (海洋湖沼学报（英文）)

年 卷 期：2022年第40卷第2期

页      面：470-484页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 

基　　金：Supported by the National Natural Science Foundation of China(Nos.42176174,41706196) the Sichuan Science and Technology Program(No.2018JY0484) the Natural Science Key Research Program of Education Department of Sichuan Province(No.18ZA0103) the China Postdoctoral Science Foundation(No.2020M683258) the Provincial Science and Technology Innovation Development Project of China Meteorological Administration(No.SSCX2020CQ) the Chongqing Technology Innovation and Application Development Special Project(No.cstc2020jscx-msxmX0193) the Chongqing Meteorological Department Business Technology Research Project(No.YWJSGG-202017) 

主　　题：synthetic aperture radar(SAR) Doppler frequency Doppler frequency anomaly current retrieval ocean surface currents 

摘      要：Values for Doppler center frequency are calculated from the echo signal at the satellite using the Doppler centroid method and so include the predicted Doppler frequency caused by the relative motion of the satellite and the Earth,which is the main component of Doppler center frequency and must be removed to obtain the Doppler frequency anomaly for ocean current *** this paper,a new Doppler frequency anomaly algorithm was proposed when measuring surface currents with synthetic aperture radar(SAR).The key of the proposed algorithm involved mean filtering method in the range direction and linear fitting in the azimuth direction to remove the radial and the azimuthal component of predicted Doppler frequency from the Doppler center frequency,*** basis is that the theoretical Doppler center frequency model of SAR exhibits an approximately linear characteristic in both the range direction and in the azimuth *** the help of the new algorithm for predicted Doppler frequency removal,the estimation error of Doppler frequency anomaly can be reduced by avoiding employing the theoretical antenna pattern and imperfect satellite attitude parameters in the conventional Doppler frequency *** measurement results demonstrated that,compared to the conventional Doppler frequency with/without error correction method,the proposed algorithm allows for a pronounced improvement in the current measuring accuracy in comparison with the global ocean multi-observation(MOB)*** addition,the eff ectiveness and robustness of the proposed Doppler algorithm has been demonstrated by its application in the high velocity current in the Kuroshio region.