Abstract: Because of the high quality and the open source policy of the Sentinel-1 SAR data, InSAR studies using Sentinel-1 is essential for technology promotion and application. However, the characteristics of TOPS acquiring mode bring in challenges for the interferogram generation of Sentinel-1 data. This paper implements quantitative analyses of three main issues that causing poor quality of Sentinel-1 interferogram of TOPS mode, including image coregistration, ionosphere phase correction and troposphere phase correction. After that, an effective solution based on ESD algorithm, GPS data and ECMWF data is proposed to solve the aforementioned problems. A pair of Sentinel-1 TOPS mode images acquired in 2016 are chosen as the study data. It turns out that the derived interferogram achieves the requirement of 1/1000 coregistration precision, in conjunction with the corrected linear trend and burst phase-jump from ionosphere difference. The phase error due to the troposphere difference reduces approximately 27% in standard deviation after the tropospheric phase correction. The proposed solution significantly enhances the quality of Sentinel-1 TOPS mode interferogram that is feasible in motion estimation using DInSAR and time series DInSAR approaches.

Key words: Sentinel-1, TOPS, coregistration, atmospheric correction, deformation monitoring