Synthetic aperture sonar motion compensation algorithm using dual-sided echo

The slant-range error of the synthetic aperture sonar array can be estimated by using the single-sided echo,but the sway and the heave cannot be distinguished.Aiming at this problem,a motion compensation method using dual-sided echoes is proposed.Firstly,the motion errors model of the dual-sided array is established based on the geometric relationship of the dual-sided array motion errors.Then,sway and the heave are estimated by combining the displaced phase center algorithm.Finally,motion compensation is performed for echo signals at different grazing angles using the estimated motion errors.The simulation result shows that the proposed method can accurately estimate the motion errors of the dual-sided array,the deviation between the estimated value and the actual value is about 10-4 m,and the standard deviation of estimated results is close to the Cramer-Rao lower bound.After the motion compensation,a better imaging can be obtained.The imaging results of the lake test data of the underwater ball string target show that,compared with the motion compensation method based on single-sided echo,the proposed method can suppress defocusing more effectively.