On the De-ramping of SLC-IW TOPS SAR data and Ocean Circulation Parameters Estimation

SAR provides high-resolution images of large geographic areas. The spectral characteristics of SLC-IW TOPS (terrain observation by progressive scan) are significantly different from those of strip-map (SM). Due to the burst mode and series of sub-swaths, the target area is scanned for a short period of time. Therefore, swath width comes at the expense of azimuth resolution. To eliminate quadratic phase drift and achieve SLC baseband, significant processing is required. De-ramping is a necessary step to compute ocean circulation parameters. In this work, ocean parameters are extracted from the complex echo signal based on data-driven doppler centroid (DC) regardless of the OCN product information and geophysical \(f_{Dc}\) image. The radial surface velocity (RSV) is retrieved by DC history, and the significant wave height (SWH) is estimated with an empirical relationship to RSV. The results of ocean circulation parameters are promising when compared with benchmark and in-situ data. This work demonstrates the efficacy and necessity of de-ramping the TOPS data for subsequent use in a variety of ocean remote sensing applications.