Sound velocity profile signal processing system and method for use in sonar systems

摘要

A method and apparatus for calculating a sound velocity or sound velocity error in an ocean, gulf, sea, bay, littoral region, lake, or river at a first locale using a sensing system (for example, a sonar system) having at least one sensor. The technique includes calculating echo time data of a first sounding which is projected in the direction of the first locale at a first angle; calculating first bathymetric data for the first locale using echo time data of the first sounding; calculating echo time data of a second sounding which is projected in the direction of the first locale at a second angle; calculating second bathymetric data for the first locale using echo time data of the second sounding; and calculating sound velocity at the first locale using the first bathymetric data and the echo time data of the first sounding and second bathymetric data and the echo time of the second sounding. The sound velocity error and/or sound velocity may be used to further calculate a sound velocity profile, sound velocity error profile, sound velocity gradient, and sound velocity error gradient. The signal processing unit employs the sound velocity error, sound velocity, sound velocity profile, sound velocity error profile, sound velocity gradient, and/or sound velocity error gradient to "correct" erroneous bathymetric data caused by changes in the sound velocity. The velocity of sound varies at a given location according to temperature, salinity, and pressure or depth.