On the De-Ramping of SLC-IW Tops SAR Data and Ocean Circulation Parameters Estimation

Abstract

The spectral characteristics of single-look complex -interferometric wide (SLC-IW) swath, terrain observation by progressive scan (TOPS), 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, we extract ocean parameters from the complex echo signal based on data driven Doppler centroid (f DC ) regardless of the OCN product information and geophysical f DC image. The radial surface velocity (RSV) is retrieved from Doppler history, and the significant wave height (SWH) is estimated with an empirical relationship of 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.

Coastline Extraction From SAR Data Using Doppler Centroid Images

“…To study this footprint, we estimate Doppler velocity (V D ) [18], which varies up to 2.25 m/s and significant wave height (SWH) [19], that goes up to 1.45 m. The distributions of Doppler parameters of three data sets are presented in red, green, and blue plots, where data-3 (in blue) has the majority of its distribution around zero, which states the sea state condition is very calm. This study helps monitoring of coastline and delineates natural hazards to protect the shoreline.…”

Synthetic Aperture Radar (SAR) for Ocean: A Review

“…The Doppler shift of the backscattered SAR signal can be measured through the difference between the Doppler centroid of the SAR data and the nominal Doppler centroid calculated using the trajectory parameters of the satellite orbit [83]. Furthermore, the wave component should be extracted from the Doppler shift to improve accuracy in ocean surface current estimation [84], [85]. It is worth noting that there is a two-way relationship between ocean surface wind and current [10] and, thus, considering them together in studies of ocean surface parameters would result in a better accuracy [10].…”

Emprego da Técnica PSInSAR como Ferramenta Complementar em Análise de Subsidências. Caso de Estudo: Bairro Guabirotuba – Curitiba – PR

“…Inicialmente, as imagens SAR foram préprocessadas no SNAP, uma plataforma desenvolvida pela European Space Agency (ESA) para o processamento e análise de dados dos satélites das missões Sentinel. Nessa etapa, as imagens passaram por uma série de procedimentos, incluindo a atualização das órbitas, a geocodificação e o processo de debursting, que determina os valores de alcance na área de sobreposição entre as faixas das imagens SAR, eliminando as linhas escuras formadas entre elas e resultando em uma imagem final contínua (MANDAL et al, 2019;IQBAL;ANGHEL;DATCU, 2022). Além disso, foi realizado o recorte da área de estudo e gerados os interferogramas que, posteriormente, foram utilizados na etapa de processamento empregando a técnica PSInSAR no ambiente do StaMPS, onde se identificaram os PS sobre a área de estudo.…”