A Detection Method of Frequency Modulated Signals Based on Robust Subband STMV

The traditional beamforming (CBF) has insufficient side-lobe leakage and interference suppression capabilities. Therefore, in a strong interference environment, the time-domain detection performance of active frequency-modulated pulse signals significantly degrades. The Robust Subband Spatial-Temporal-Matched-Vector algorithm (RSBMV) is combined with matched filtering (MF) as follows: 1) The frequency-domain signal is divided into subbands, and independent constraints are imposed on the steering vector errors of different subbands to enhance the robustness of noise suppression; 2) A matched filter is designed for the time-domain data of the beam output to alleviate the problem of signal distortion under noise interference. The signal-to-noise ratio of the correlation peak output of RSBMV+MF is approximately 1 dB higher than that of CBF+MF, and the main lobe width is reduced by 50%. This method can provide a highly robust and low-complexity solution for the detection of active frequency-modulated signals in sonar systems in noise interference environments, and it has the potential for engineering applications.