Multi-Lag Amplitude-Normalized Correlation for Doppler-Robust Wideband Sonar Bottom Bathymetry Using Maximum-Length Sequence

This paper presents a robust bottom detection technique for broadband Doppler velocity logs. Conventional log-envelope methods suffer from performance degradation due to amplitude distortion in severe multipath fading environments. To address this problem, we propose an amplitude normalization-based correlation processing scheme utilizing maximum-length sequence (M-sequence) repetition and a multi-lag correlation energy fusion technique. This approach improves correlation peak sharpness by excluding amplitude information and enhances noise immunity through asynchronous fusion of multi-lag correlation energies. Simulation results demonstrate superior range resolution and detection probability compared to existing methods, even in low signal-to-noise ratio conditions.