Focusing forward-looking linear-array synthetic aperture radar with high speed based on keystone transform and modified nonlinear chirp scaling algorithm

Abstract

For forward-looking linear-array synthetic aperture radar with high speed, the traditional algorithm neglects its high speed, which leads to poor focusing imaging quality. Due to the high speed movement of the platform, range cell migration (RCM) and two-dimensional spatial variation are more serious. To overcome this problem, an equivalent range model is proposed, which takes the platform’s high speed into consideration. Based on this model, linear range walk correction and second-order keystone transform method are used to eliminate the RCM and range-azimuth coupling, and then a modified nonlinear chirp scaling algorithm based on a circle model is used to improve the focus quality of edge targets. Finally, simulation results are presented to confirm the efficiency of the proposed algorithm.