PRELIMINARY EVALUATION OF GAOFEN-3 POLARIMETRIC AND RADIOMETRIC ACCURACY BY CORNER REFLECTORS IN INNER MONGOLIA

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

Yang, J.^1¹  Ding, X.^2²  Li, P.^1³  Shi, L.^1⁴ 

[1] China Centre For Resources Satellite Data and Application^4;Department of Land Surveying and Geo-Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong^2;School of Remote Sensing and Information Engineering, Wuhan University, China^3;State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, China^1

关键词: Gaofen-3;    Quality evaluation;    Polarimetric and Radiometric accuracy;   

DOI  :  10.5194/isprs-archives-XLII-3-1543-2018

学科分类：地球科学(综合)

来源: Copernicus Publications

【 摘 要 】

On August 10, 2016, China launched its first C-band full polarimetric radar satellite, named Gaofen-3 (GF-3), for urban and agriculture monitoring, landslide detection, ocean applications, etc. According to the design specification, GF-3 is expected to work at −35 dB crosstalk and 0.5 dB channel imbalance, with less than 10 degree error. The absolute radiometric bias is expected to be less than 1.5 dB in a single scene and 2.0 dB when operating for a long time. To complete the calibration and evaluation, the Institute of Electronics, Chinese Academy Sciences (IECAS) built a test site at Inner Mongolia, and deployed active reflectors (ARs) and trihedral corner reflectors (CRs) to solve and evaluate the hardware distortion. To the best of the authors’ knowledge, the product accuracy of GF-3 has not been comprehensively evaluated in any open publication. The remote sensing community urgently requires a detailed report about the product accuracy and stability, before any subsequent application. From June to August of 2017, IECAS begun its second round ground campaign and deployed 10 CRs to evaluate product distortions. In this paper, we exploit Inner Mongolia CRs to investigate polarimetric and radiometric accuracy of QPSI I Stripmap. Although some CRs found fall into AR side lobe, the rest CRs enable us to preliminarily evaluate the accuracy of some special imaging beams. In the experimental part, the image of July 6, 2017 was checked by 5 trihedral CRs and the integration estimation method demonstrated the crosstalk varying from −42.65 to −32.74 dB, and the channel imbalance varying from −0.21 to 0.47 with phase error from −2.4 to 0.2 degree. Comparing with the theoretical radar cross-section of 1.235 m trihedral CR, i.e. 35 dB, the radiometric error varies about 0.20 ± 0.29 dB in HH channel and 0.40 ± 0.20 dB in VV channel.

【 授权许可】

CC BY