Phase Correction for Accurate DOA Angle and Position Estimation of Ground Moving Targets using Multi-Channel Airborne Radar

Abstract

Accurate position estimation of the ground moving targets is a crucial requirement for any radar-based surveillance system. For multi-channel airborne radar, the target position on ground can be accurately obtained by estimating the direction-of-arrival (DOA) angle of the moving targets. However, in practice the aircraft motion caused by atmospheric turbulence tilts the antenna array and introduces undesired phase differences among the multiple receive channels. As a result, the accuracy of the estimated DOA angles can be severely affected. This letter presents a robust and efficient algorithm that corrects the undesired phase differences among the multiple receive channels. By doing this, accurate DOA angles and, therefore, accurate target positions on the ground can be estimated. Important inputs of the proposed algorithm are the precise absolute positions of the receive channels and the elevation of the terrain. The performance of the proposed algorithm is validated using both simulated and real radar data acquired with the DLR’s multi-channel airborne system DBFSAR.