S波段高分辨宽幅SAR辐射定标及误差分析方法
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摘要
合成孔径雷达(SAR)系统的辐射定标可以构建SAR图像与地物后向散射截面积(RCS)的关系,反演目标物理特性,满足SAR定量化遥感需求。相对于其它波段,S波段SAR的定量化遥感工作罕见报道。该文利用已知SAR及平台参数进行S波段SAR辐射定标处理,首先推得了图像像素值与目标后向散射系数的关系,接下来详细分析了各项误差对定标精度的影响,给出了天线指向误差对定标精度影响的解析表达式。该文的分析有利于建立各参数与辐射定标精度的关系,方便设计时候的误差分配。该文给出了草地、道路和平静水面的S波段后向散射截面积统计值。最终实际数据处理结果表明,该系统利用该定标方法可以在20°的视角范围内实现较高的绝对辐射精度。
The radiometric calibration of Synthetic Aperture Radar(SAR) can establish a mapping relationship between SAR image and Radar Cross Section(RCS) of ground objects, which benefits the inversion of target physical properties, and further meets the needs of quantitative remote sensing. Compared with other wavebands, the reports about SAR works in S-band are rare. This paper focuses on the radiometric calibration of radar at S-band by using the known parameters of radar and plane. Firstly, the relationship between image pixel intensity and RCS of target is derived. Then, a detailed analysis on each error component is implemented,in which, the affection of antenna direction on radiometric calibration precision is given by the analytic expression. The analysis and simulation is propitious to error allocation during the design period. In addition,the mean RCS statistics of grass, road and calm water are given. The real data processing results show that a sufficient accuracy in 20° view angle can be achieved by using the radiometric calibration method.
The radiometric calibration of Synthetic Aperture Radar(SAR) can establish a mapping relationship between SAR image and Radar Cross Section(RCS) of ground objects, which benefits the inversion of target physical properties, and further meets the needs of quantitative remote sensing. Compared with other wavebands, the reports about SAR works in S-band are rare. This paper focuses on the radiometric calibration of radar at S-band by using the known parameters of radar and plane. Firstly, the relationship between image pixel intensity and RCS of target is derived. Then, a detailed analysis on each error component is implemented,in which, the affection of antenna direction on radiometric calibration precision is given by the analytic expression. The analysis and simulation is propitious to error allocation during the design period. In addition,the mean RCS statistics of grass, road and calm water are given. The real data processing results show that a sufficient accuracy in 20° view angle can be achieved by using the radiometric calibration method.
引文
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[12]汪伟,李军,胡庆荣.基于点目标的机载毫米波SAR辐射定标[C].第三届高分辨率对地观测学术年会分会论文集,北京,2014:502-513
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[14]郑晨,黄磊,陈权.点目标的机载SAR辐射定标实验精度分析[J].遥感信息,2015,30(4):14-19.doi:10.3969/j.issn.1000-3177.2015.04.003.ZHENG Chen,HUANG Lei,and CHEN Quan.Accuracy of airborne SAR radiometric calibration with point target[J].Remote Sensing Information,2015,30(4):14-19.doi:10.3969/j.issn.1000-3177.2015.04.003.
[15]ULABY F T and DOBSON M C.Handbook of Radar Scattering Statistics for Terrain[M].Norwood,MA:Artech House,Inc.,1989:173-177.
[2]SCHWERDT M,HOUNAM D,ALVAREZ-PEREZ J L,et al.TerraSAR-X:Calibration concept of a multiple modehigh resolution SAR[C].The 25th International Geoscience and Remote Sensing Symposium,2005,Seoul,Korea,2005:4874-4877.doi:10.1109/IGARSS.2005.1526766.
[3]CHEN Quan,LI Zhen,ZHANG Ping,et al.A preliminary evaluation of the GaoFen-3 SAR radiation characteristics in land surface and compared with radarsat-2 and Sentinel-1A[J].IEEE Geoscience and Remote Sensing Letters,2018,15(7):1040-1044.doi:10.1109/LGRS.2018.2821238.
[4]ZHANG Linjian,GAO Yesheng,WANG Kaizhi,et al.Asubspace algorithm of calibrating channel gain and phase errors for HRWS SAR imaging[C].2017 IEEE Radar Conference,Seattle,USA,2017:269-272.doi:10.1109/RADAR.2017.7944210.
[5]LI Huimin,MOUCHE A,STOPA J E,et al.Calibration of the normalized Radar Cross Section for Sentinel-1 wave mode[J].IEEE Transactions on Geoscience and Remote Sensing,2019,57(3):1415-1522.doi:10.1109/TGRS.2018.2867035.
[6]GUCCIONE P,SCAGLIOLA M,and GIUDICI D.Lowfrequency SAR radiometric calibration and antenna pattern estimation by using stable point targets[J].IEEETransactions on Geoscience and Remote Sensing,2018,56(2):635-646.doi:10.1109/TGRS.2017.2752228.
[7]SCHMIDT K,RAMON N T,and SCHWERDT M.Radiometric accuracy and one-year-stability of sentinel-1Adetermined using point targets[C].The 47th European Microwave Conference,Nuremberg,Germany,2017:1075-1078.doi:10.23919/EuMC.2017.8231058.
[8]SCHWERDT M,BRAUTIGAM B,BACHMANN M,et al.Final TerraSAR-X calibration results based on novel efficient methods[J].IEEE Transactions on Geoscience and Remote Sensing,2010,48(2):677-689.doi:10.1109/TGRS.2009.2035308.
[9]SCHWERDT M,BRAEUTIGAM B,BACHMANN M,et al.TerraSAR-X calibration results[C].7th European Conference on Synthetic Aperture Radar,Friedrichshafen,Germany,2008:1-4.doi:10.1109/IGARSS.2008.4778963.
[10]TOUZI R,HAWKINS R K,and COTO S.High-precision assessment and calibration of polarimetric RadarSAT-2SAR using transponder measurements[J].IEEE Transaction on Geoscience and Remote Sensing,2013,51(1):487-503.doi:10.1109/TGRS.2012.2201946.
[11]SHEN Ting,LI Jun,WANG Zhirui,et al.The airborne X-SAR calibration with high resolution[C].2016 CIEInternational Conference on Radar(RADAR),Guangzhou,China,2017:1-5.doi:10.1109/RADAR.2016.8059209.
[12]汪伟,李军,胡庆荣.基于点目标的机载毫米波SAR辐射定标[C].第三届高分辨率对地观测学术年会分会论文集,北京,2014:502-513
[13]周晓,曾琪明,焦健,等.星载SAR传感器外场定标实验研究-以TerraSAR-X卫星为例[J].遥感技术与应用,2014,29(5):711-718.ZHOU Xiao,ZENG Qiming,JIAO Jian,et al.Research on Space-borne SAR field calibration experiment-A case study of TerraSAR-X field calibration[J].Remote Sensing Technology and Application,2014,29(5):711-718.
[14]郑晨,黄磊,陈权.点目标的机载SAR辐射定标实验精度分析[J].遥感信息,2015,30(4):14-19.doi:10.3969/j.issn.1000-3177.2015.04.003.ZHENG Chen,HUANG Lei,and CHEN Quan.Accuracy of airborne SAR radiometric calibration with point target[J].Remote Sensing Information,2015,30(4):14-19.doi:10.3969/j.issn.1000-3177.2015.04.003.
[15]ULABY F T and DOBSON M C.Handbook of Radar Scattering Statistics for Terrain[M].Norwood,MA:Artech House,Inc.,1989:173-177.