High‐resolution SAR altimeter with wide‐angle echoes coherent accumulation

Abstract

Wide-angle synthetic aperture radar (SAR) altimeters, which are able to obtain higher azimuth resolution and better height measurement result, demonstrate a promising prospect of application. Accumulating scattering echoes received from different angles can greatly suppress noise and promote estimation accuracy. However, traditional methods of accumulation cannot work well in wide-angle SAR altimeters due to variety of scattering characteristics. To address this problem, this study first researches on basic principles, scattering function and signal models of wide-angle SAR altimeters. Based on these models, echoes of various angles are coherent accumulated to estimate the parameters. A cylindrical target on the sea surface is used as an example in the simulation. The results indicate that the precision of parameter estimation is improved by two to four orders of magnitude if the scattering characteristics varying with azimuth angles are taken into account in the step of echoes accumulation.