A receive-coherent detector for airborne distributed coherent aperture radar under heterogeneous clutter and random phase errors

Airborne distributed coherent aperture radar (ADCAR) obtain target coherent parameters (TCPs) and improve target detection performance significantly in the receive-coherent (RC) stage by multiple physically isolated airborne radars with orthogonal waveforms. However, the heterogeneous clutter with unknown power arising from imperfect orthogonal waveforms, and the random phase errors (RPE) introduced by phase synchronization between nodes, all of which cause severe degradation of detection performance. In this paper, we propose a RC signal model of ADCAR in cluttered environments under the RPE modeling by the von Mises distribution. Then, a two-step RC generalized likelihood ratio test (GLRT) detector with a simplified expectation maximization (EM) algorithm (2S-RVEM-G) is proposed, which iteratively solves for the unknown parameters under the alternative hypotheses by the EM algorithm to achieve target detection of ADCAR under heterogeneous clutter and RPE. Then, a detection strategy without prior information is proposed to enhance the proposed algorithm’s feasibility further. Finally, experimental results indicate that the target detection performance of 2S-RVEM-G is better than the traditional detectors, and the proposed strategy also ensures decent performances without prior information, proving the proposed method’s effectiveness.