Correcting method of slant-range error for the TH-2 satellites

• Published in: Remote sensing letters Vol. 12; no. 2; pp. 142 - 149
• Main Authors: Qian, Fangming, Chen, Gang, Lu, Jun, Chen, Xiangming, Lou, Liangsheng, Jiang, Ting, Liu, Wei, Wang, Sai
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.02.2021; Taylor & Francis Ltd
• Subjects: Accuracy; Data analysis; Data processing; Delay; Error correction; Interferometric synthetic aperture radar; Mathematical analysis; Pixels; Range errors; Ray tracing; Reflectors; SAR (radar); Satellites
• DOI: 10.1080/2150704X.2020.1864054
• ISSN: 2150-704X

A method of correcting the slant-range error of the space-borne interferometric synthetic aperture radar (InSAR) system aboard the TH-2 satellites is proposed. First, we calculate the tropospheric-delay using the third-order fractional mapping-function method, and we calculate the ionospheric-delay using the ray-tracing method. The calculations show that the atmospheric-delays for the TH-2 ranges from 2.23 m to 3.08 m in four areas. Next, From the channel-delay at corner-reflectors (CRs), we determine the average channel-delay to be 4.02 m from data-processing results for 22 scenes. Finally, we use the field data obtained by TH-2 to evaluate the effect of the slant-range correction. After correcting for the slant-range error, the accuracy of image-point coordinate prediction in the range direction is improved from about 7 pixels to less than one pixel. The ground-point positioning accuracy in elevation is also improved by about 4.65 m, and the plane accuracy approaches the elevation accuracy. The method proposed in this paper has been used to correct the slant-range error of TH-2, and the expected results have been achieved.