Range Ambiguity Mitigation and Range-Angle Estimation With EPC-FDA-MIMO Radar

Abstract

Range ambiguity is common for estimating range with the multiple-input–multiple-out (MIMO) radar employing elevated pulse repetition frequency (PRF). Despite that the frequency diverse array (FDA) or element-pulse coding (EPC) in transmitter provides possibility for resolving range ambiguity at a single PRF, the involved orthogonal waveform sequences are unpractical in pulse-Doppler radars. In this article, the MIMO-based hybrid of FDA and EPC is investigated to mitigate range ambiguity and enhance range resolution, which is so called EPC-FDA-MIMO. Employing the ampliative frequency offset in transmit antennas is to guarantee the orthogonality in frequency domain. The EPC scheme is employing the Fourier basis on the element-pulse dimension in transmitter. The associated receive processing approach is designed, which is characterized by the subband synthesis in frequency domain and the three-stage range-angle estimator. The subband synthesis is devised to enhance range resolution by utilizing the synthesized bandwidth. A three-stage estimator involves estimating angle in receive domain, estimating range region number and range quantization error in transmit domain. Further, the Cramér–Rao bounds for EPC-FDA-MIMO system are also conducted to examine the estimation performance of the range-angle estimator. Numerous simulation results are provided to verify the effectiveness of the proposed method.