Joint Range Angle and Velocity Estimation Method for FDA-MIMO Radar under Clutter Background

One of the foremost tasks of radar systems is target localization, which is mainly characterized by target range, angle, and velocity. The frequency diverse array multiple-input and multiple-output (FDA-MIMO) radar has been widely applied in parameter estimation due to its additional range information introduced by FDA and increased transmit degrees-of-freedom brought by MIMO. However, the effect of frequency diversity on Doppler frequency has not been thoroughly investigated, and the existing estimators usually consider clutter-free background, which is oversimplified to hold in practice. In this article, a joint range angle and velocity estimation method is proposed for FDA-MIMO radar under both clutter-free and clutter backgrounds. First, we analyze the inner bin range dependence (IRD) property of clutter scatterers within the same range bin and the angle-Doppler defocusing (ADD) property of high-speed moving targets. Then, a three-stage search-based method is proposed for joint range angle and velocity estimation. In particular, the velocity ambiguity problem can be solved by exploiting the coupling relationship between the transmit carrier frequency and the target velocity. In the sequel, the multiple parameters estimation performance is evaluated with respect to the signal-to-noise ratio (SNR) and the number of snapshots. Moreover, the velocity ambiguity resolvability of the proposed method is compared with a typical existing method in relation to the SNR and the number of pulses. Numerical results demonstrate the effectiveness of the proposed method and show that it has lower requirement on SNR and the number of pulses.