A Biphase Code Sidelobe Suppression Method Based on the CLEAN Algorithm

In the processing of biphase-coded signals, if the moment of ADC sampling coincides with the transition edge of the code inversion, it can result in the loss of peak information. This loss leads to a reduction in the peak energy of pulse compression and diminishes the mainlobe-to-sidelobe ratio. To address this issue, this paper proposes a sidelobe suppression method based on the CLEAN algorithm. First, the digital moving target detection (DMTD) algorithm is employed to estimate the target velocity, and the phase of the echo signal is dynamically adjusted to eliminate straddle loss. Subsequently, through Doppler compensation techniques and optimized pulse compression processing, the energy loss caused by Doppler mismatch is minimized. Finally, the sidelobes of the signal are suppressed using the CLEAN algorithm. Simulation results indicate that, under low SNR conditions, when processing a biphase-coded signal modulated by a 255-bit M-sequence, the degree of sidelobe suppression can reach 27.7 dB.