基于相关干扰抑制的 MIMO 声呐波形设计

In the multiple-input multiple-output (MIMO) sonar system, realizing the ideal orthogonality of emission signals is difficult because it requires the lowest possible cross-correlation peak level (CPL) and autocorrelation side-lobe peak level (ASPL) simultaneously among transmitted waveforms. Analysis shows that high ASPL exists in the traditional orthogonal frequency division multiplexing linear frequency modulation (OFDM-LFM) waveform. Two new design plans for waveform structure, namely, optimizing subpulse frequency modulation bandwidth and frequency modulation time width, are proposed by adopting the idea of signal segmentation design to solve the aforementioned problem and optimize the LFM signal structure of each transmitting array element. Therefore, the degree of freedom of the transmitted signals is increased to ensure the easy generation of the waveform. Simulation results show that the waveforms designed in the two abovementioned methods have lower ASPL and CPL compared with the traditional OFDM-LFM waveform.