Patent ID: 7342847

Claim:
A method of estimating along-track displacement of an underwater vehicle, comprising the steps of: providing an underwater vehicle equipped with a synthetic aperture sonar (SAS) system that includes a transmitter and a plurality of spaced-apart receivers linearly aligned along the vehicle; operating said SAS system as the vehicle moves through the water so that (i) the transmitter transmits first and second acoustic transmissions into the water, and (ii) said receivers detect first and second acoustic signals caused by said first and second acoustic transmissions, respectively; determining cross-correlations between said first and second acoustic signals for a plurality of possible along-track (AT) redundant phase center (RPC) overlap scenarios; averaging said cross-correlations for each of said plurality of possible AT RPC overlap scenarios to generate an average cross-correlation value for each of said plurality of possible AT RPC overlap scenarios, wherein a corresponding plurality of average cross-correlation values are generated; and determining a peak cross-correlation value using said plurality of average cross-correlation values, said peak cross-correlation value corresponding to an actual AT RPC overlap scenario that is indicative of along-track displacement of the underwater vehicle occurring between detections of said first and second acoustic signals.