A method for self-calibration of motion and attitude of two-dimensional sonar array

Abstract

The invention provides a self-calibration method for the movement and attitude of a two-dimensional sonar array. First, pulse compression processing is performed on the echo signal received by the sonar array, and the integer times delay and the minimum time delay of the "sound point" from each vertex of the array are estimated respectively. Several times the delay, combined with the two-dimensional matrix aperture to establish a nonlinear overdetermined equation system. The objective function is constructed for the obtained nonlinear overdetermined equation system, and the gradient method is used to iteratively solve the least squares solution of the equation system, so as to obtain the center of the two-dimensional matrix at the current sampling position, the translation error and the position of the four vertices. The nonlinear overdetermined equation system is established again by using the system rotation matrix, and the attitude error is obtained by iterative solution. This method can realize the joint self-calibration process of the six-degree-of-freedom motion error of the motion attitude of the two-dimensional array by establishing the geometric equation for the time delay estimation of the echo signal and the array structure. High accuracy, good real-time algorithm and other technical advantages.

Description

technical field [0001] The invention relates to a self-calibration method for the movement and attitude of a two-dimensional sonar base array, which belongs to the field of sonar signal processing. Background technique [0002] Imaging sonar is the most commonly used underwater topography detection technology. It has developed a number of technical branches, and has received extensive research and attention from academic institutions and sonar equipment manufacturers. Common imaging sonar equipment mainly includes side scan sonar, multi-beam bathymetric sonar, and synthetic aperture sonar. These imaging sonar devices realize the two-dimensional or three-dimensional imaging process of the detection area by transmitting and receiving acoustic signals. The motion attitude estimation and compensation of the sonar array carrier is an important factor for sonar imaging and post-processing. Accurate attitude estimation and compensation is an important guarantee for stable mapping ...

AI Technical Summary

Problems solved by technology

Among them, hardware estimation mainly refers to the estimation method based on external motion estimation auxiliary equipment such as attitude instrument, compass, and GPS. The use of a space-tight cabin limits the application in an underwater unmanned environment; software estimation is mainly in the synthetic aperture sonar system, which uses the self-focusing method of the target echo to estimate the motion attitude, and then performs imaging compensation. The advantage is the cost. Saving, no need to add additional external auxiliary equipment, the disadvantage is that the existing method is not fully applicable to the two-dimensional sonar array structure

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