Improved displaced phase center algorithm based on time-delay and phase estimations

The image reconstruction of a multi-hydrophone SAS (Synthetic Aperture Sonar) has been an active research topic at present. Yaw and sway are the key factors which result in distorted image and loss of resolution. Based on the deep study of displaced phase center algorithm, an improved movement error estimation algorithm for multi-hydrophone SAS was proposed. With this method, the difference between the actual path length and the approximated path length using equivalent phase center was revised, and the yaw and sway were estimated utilizing the time-delay and phase estimations. The effect of echo interference on estimation was avoided by the improved algorithm. Through these ways, the movement error scope that could be estimated was extended and the accuracy of movement error estimation was improved. Simulation results show that the improved algorithm estimates the movement error effectively and the imaging quality is enhanced.