Simultaneous Design of PCFM Waveforms and Receive Filters Toward ISRJ Suppression

The interrupted sampling repeater jamming (ISRJ) is a widely used coherent jamming technique. A proper waveform design can effectively suppress or mitigate the ISRJ. Even if several phase-coded waveform design methods have been proposed for this purpose, frequency modulation (FM) waveforms remain the most common choice for high-power transmitters, as they do not introduce significant distortions in real radar systems. In this letter, we propose a design method for multiple-input multiple-output (MIMO) radar that simultaneously derives the optimal polyphase-coded FM (PCFM) waveforms and the receive filters to mitigate the ISRJ. Specifically, we first model the joint design problem as a nonconvex bivariate optimization problem and we minimize the matching error between the desired and practical transmit-receive correlation functions for different channels. Subsequently, we adopt an alternating strategy to update the PCFM waveforms and receive filters sequentially. More specifically, gradient-based algorithms in Euclidean space and Riemannian manifold space are adopted to derive the optimal waveforms and filters, respectively. The proposed method is characterized by a low computational cost, thanks to its FFT-based implementation. Numerical analysis shows the effectiveness of the proposed method.