A Closed-Form Expression of STAP Performance for Distributed Aperture Coherence MIMO Radar

Distributed aperture coherence multi-input multi-output (MIMO) radar combined with space-time adaptive processing (STAP) has a great advantage for moving target indication. However, the problems of nonideal orthogonal waveform and nonstationary clutter are intertwined together, which leads to significant performance degradation of STAP. In this letter, we presented a pragmatic and accurate performance prediction model to interpret the impact mechanism of waveform properties on STAP performance. We deduced a novel clutter covariance matrix (CCM) model with the aforementioned nonideal factors taking into consideration. On this basis, a closed-form expression of output signal-to-clutter-plus-noise ratio (SCNR) loss is derived to predict and evaluate STAP performance. Therefore, the quantitative relationship is established between waveform properties, clutter CCM, and STAP performance. It provides a simple and effective way to predict system performance for radar system design. Finally, numerical simulation results illustrated that the mean prediction error of SCNR loss for the proposed model is about 2 dB less than the conventional approximation model.