Polyphase waveform design for ISRJ suppression based on L-BFGS method

In order to eliminate the false-target peaks caused by the interrupted sampling repeater jamming (ISRJ) and increase the true target detection ability in pulse compression, a polyphase radar waveform consisting of an effective time discontinuous waveform (TDW) and protection pulse (PP) is proposed in this paper. In the waveform design procedure, the ISRJ parameters, including the sampling pulse duration, sampling period and retransmitting delay, are estimated using the sliding-truncation matched filter algorithm. Based on the estimation results, the orthogonal PP and TDW are designed to fill the ISRJ sampling and retransmitting durations according to the jamming operator matrix. The phase code of radar transmitted waveform is calculated iteratively to maximize the orthogonality between the PP and TDW using the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. A mismatched filter for the TDW waveform is optimized to further suppress the false-target peak caused by the ISRJ. Numerical simulations with different jamming parameters are given to demonstrate the efficiency of the proposed method, the designed waveform exhibits a moderate target signal integration loss and a large ISRJ suppression, thereby achieves a high anti-ISRJ performance. The false-target peaks of ISRJ are eliminated and the target signal is retained simultaneously.