Velocity estimation of moving targets for spaceborne multichannel synthetic aperture radar systems based on equivalent along‐track interferometry technique

Abstract

Velocity estimation of a moving target is an important yet challenging issue facing the special mode of high-resolution and wide-swath (HRWS) synthetic aperture radar. HRWS imaging is achieved by splitting the antenna into multiple receive channels in azimuth with each channel working at low pulse repetition frequency sampling. In this study, the authors propose a novel approach to estimate the velocity of a moving target in HRWS mode, along with a complete moving target indication, estimation, and imaging scheme. The proposed radial velocity estimation algorithm is called the equivalent along-track interferometry method, which is implemented by twice imaging after reconstructing the data of several leftmost and rightmost channels. Moreover, the along-track velocity is also estimated for focused imaging of the moving target. The motion-adapted reconstruction and imaging algorithm is applied to achieve unambiguous imaging of the moving target. Experimental results verify the performance of the algorithm and its superiority for a moving target with interference from clutter, noise, and channel mismatches. The proposed algorithm is free of search and iteration, and featured by high accuracy and low computational load.