Synthetic aperture sonar motion compensation method for reducing accumulated error of DPC (Displaced Phase Center) method

Abstract

The invention discloses a synthetic aperture sonar motion compensation method for reducing the accumulated error of a DPC (Displaced Phase Center) method, which comprises the steps of receiving echo signals by synthetic aperture sonar, performing aperture division on an azimuth synthetic aperture within a complete synthetic aperture length to obtain a plurality of sub-apertures, wherein each sub-aperture contains a plurality of echo signals; performing motion error estimation and compensation on inter-ping echo signals by adopting the DPC method in the sub-apertures; and estimating and compensating a motion error between the sub-apertures in a correlation manner according to sub-aperture image data between the sub-apertures, wherein the step further comprises the sub-steps of solving matching points of sub-aperture images, performing error estimation and compensation based on the matching points and compensating the estimated error into the original echo data or using the estimated error for correcting an imaging grid.

Description

technical field [0001] The invention relates to a sonar motion compensation method, in particular to a synthetic aperture sonar motion compensation method for reducing the cumulative error of the DPC method. Background technique [0002] Synthetic aperture sonar (Synthetic Aperture Sonar: SAS) uses the movement of the small-sized matrix in the azimuth direction to form a virtual large aperture, and obtains high-resolution sonar images by coherently processing the sonar echo signals at different positions. Motion errors have a greater impact on synthetic aperture sonar imaging. The main factors that cause motion errors include the influence of wind, waves, and currents, the irregular motion of the carrier platform, the instability of the sound propagation medium, the non-uniform sound velocity, and the positioning sensor GPS and speed sensor ADL. Insufficient precision, etc. Motion error estimation and compensation is one of the important components of synthetic aperture sona...

AI Technical Summary

Problems solved by technology

Underwater navigation equipment generally has limited accuracy or is extremely expensive. In practice, motion compensation based on echo data is generally given priority

The typical motion error estimation method based on echo data is the phase center overlapping method (Displaced Phase Center, DPC), but its main problem in practical application is that when the aperture synthesis is long, with the increase of the azimuth accumulation time, The cumulative error is large and the accuracy is limited, and the method will fail in serious cases

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