Sonar data compression

A sonar data compression system comprising:

• a multibeam echo sounder for installation on a water going vehicle:
• an acoustic transceiver with plural transducers in a single linear projector array and plural transducers in a single linear hydrophone array;
• the projector array configured orthogonally with respect to the hydrophone array to form a Mills cross such that a projector array transmit beam and multiple hvdrophone array receive beams intersect;
• the acoustic transceiver synthesizing a transmitter message, the message exciting the projector array such that a swath beneath the vehicle is ensonified;
• the hydrophone array receiving transmitter message echoes and at each of multiple times tx the echoes are sampled;
• echo samples at each time tx are range gated within minimum and maximum altitudes to generate gated echo samples;
• at each time tx, the range gated echo samples processed in a beamformer;
• at each time tx, Q beams generated by the beamformer;
• each beam associated with a magnitude M that is indexed by time tx and beam number i;
• wherein for each time tx a beam with the largest magnitude (Mtx,i)max1 is identified as a characterizing beam and data associated with these characterizing beams are used as a compressed characterization of the ensonified swath.

A sonar data compression system comprising:

• a multibeam echo sounder for installation on a water going vehicle:
• an acoustic transceiver with plural transducers in a single linear projector array and plural transducers in a single linear hydrophone array;
• the projector array configured orthogonally with respect to the hydrophone array to form a Mills cross such that a projector array transmit beam and multiple hydrophone array receive beams intersect;
• the acoustic transceiver synthesizing a transmitter message including plural different signals SS1 . . . SSn;
• the message exciting the projector array such that a swath beneath the vehicle is ensonified;
• the hydrophone array receiving transmitter message echoes and at each of multiple times tx the echoes are sampled;
• echo samples at times tx result in n signals processed in n beamformers;
• at each time tx, Q beams generated by each of n beamformers;
• each beam associated with a magnitude M that is indexed by time tx and beam number i;
• wherein for each time tx and for each of n signals, a beam with the largest magnitude (Mtx,i)maxn1 is identified as a characterizing beam and data associated with these characterizing beams are used as a compressed characterization of the ensonified swath.

A sonar data compression system comprising:

• a multibeam echo sounder for installation on a water going vehicle:
• an acoustic transceiver with plural transducers in a single linear projector array and plural transducers in a single linear hydrophone array;
• the projector array configured orthogonally with respect to the hydrophone array to form a Mills cross such that a projector array transmit beam and multiple hvdrophone array receive beams intersect;
• the acoustic transceiver synthesizing a transmitter message, the message exciting the projector array such that a swath beneath the vehicle is ensonified;
• the hydrophone array receiving transmitter message echoes and at each of multiple times tx the echoes are sampled;
• at each time tx, echo samples processed in a beamformer;
• at each time tx, Q beams generated by the beamformer;
• each beam associated with a magnitude M that is indexed by time tx and beam number i;
• wherein for each time tx beams with the largest N magnitudes (Mtx,i)max1 . . . maxN are identified as a characterizing beams associated with angle αx,1 . . . N;
• for each time tx, a split array phase difference technique is applied where each subarray is steered in direction αx,1 . . . N;
• wherein the output of the technique provides an improved estimate of echo arrival angle relative to the array face and
• the magnitude from the characterizing beams and the improved angle estimates are used as a compressed characterization of the ensonified swath.

A sonar data compression system comprising:

• a multibeam echo sounder for installation on a stationary platform:
• an acoustic transceiver with plural transducers in a single linear projector array and plural transducers in a single linear hydrophone array;
• the projector array configured orthogonally with respect to the hydrophone array to form a Mills cross such that a projector array transmit beam and multiple hydrophone array receive beams intersect;
• the acoustic transceiver synthesizing a transmitter message, the message exciting the projector array such that a swath is ensonified;
• the hydrophone array receiving transmitter message echoes and at each of multiple times tx the echoes are sampled;
• at each time tx, echo samples processed in a beamformer;
• at each time tx, Q beams generated by the beamformer;
• each beam associated with a magnitude M that is indexed by time tx and beam number i;
• wherein for each time tx a beam with the largest magnitude (Mtx,i)max1 is identified as a characterizing beam;
• and,
• data associated with these characterizing beams are used as a compressed characterization of the ensonified swath.