Model-Based Sonar Motion Compensation for Bottom Reverberation Coherence

Much signal processing in sonar takes advantage of ping-to-ping bottom reverberation coherence. However, bottom reverberation coherence is degraded owing to environment variations including unknown sonar sensor motions from platform instability. In this paper, an algorithm is described to compensate small-scale motion of high-frequency sonar sensors which is for enhancing ping-to-ping bottom reverberation coherence. The algorithm is based on sonar modeling of bottom reverberation. It comprises three steps: template selection, footprint matching, and phase rotation. Simulations using the sonar modeling indicate that the algorithm can correct for sensor motion of up to several wavelengths for two pings using the data from only one element of the sonar receiver. The algorithm achieves a significant coherence improvement over a large region ensonified by the sonar beam.