Sonar data compression

A sonar data compression system comprising:

• a multibeam echo sounder situated in a waterbody;
• an acoustic transceiver for synthesizing a transmitter message, the message for exciting an array of plural projectors such that a geometric space in the waterbody is ensonified;
• an array of plural hydrophones for receiving transmitter message echoes and at each of multiple times t1, t2 . . . 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;
• and,
• each beam associated with a magnitude Mtx,i that is indexed by time tx and beam number i;
• wherein for each time tx a beam with the largest magnitude (Mtx,i)max2 is identified as a characterizing beam and data associated with these characterizing beams are used as a compressed characterization of the ensonified space.

A sonar data compression system comprising:

• a multibeam echo sounder situated in a waterbody;
• the acoustic transceiver synthesizing a transmitter message including plural different signals SS1 . . . SSn;
• the message exciting an array of plural projectors such that a waterbody space is ensonified;
• an array of plural hydrophones 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;
• and,
• each beam associated with a magnitude Mtx,i 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 space.

A sonar data compression system comprising:

• a multibeam echo sounder situated in a waterbody;
• the acoustic transceiver synthesizing a transmitter message, the message exciting an array of plural projectors such that a waterbody space is ensonified;
• an array of plural hydrophones 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 Mtx,i that is indexed by time tx and beam number i;
• for each time tx beams with the largest N magnitudes (Mtx,i)max1 . . . maxN are identified as a characterizing beams associated with beam angle αtx,1 . . . N;
• and,
• for each time tx, a split array phase difference technique is applied where each subarray is steered in the direction of beam angle αtx,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 space.

A sonar data compression system comprising:

• a multibeam echo sounder for installation on a stationary platform;
• the acoustic transceiver synthesizing a transmitter message, the message exciting an array of plural projectors to ensonify a waterbody space;
• 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 Mtx,i that is indexed by time tx and beam number i;
• and,
• for each time tx a beam with the largest magnitude (Mtx,i)max1 is identified as a characterizing beam;
• wherein data associated with these characterizing beams are used as a compressed characterization of the ensonified space.

A sonar data compression system comprising:

• an acoustic transceiver synthesizing a transmitter message, the message exciting a projector and transmitting acoustic energy into a volume of water;
• an acoustic receiver receiving acoustic echoes from a plurality of non-overlapping sub-volumes within the water volume, the sub-volumes' size defined by range resolution of the message and receiver beamwidth, and the sub-volumes' position defined by round-trip echo arrival time and angle relative to the receiver;
• sampling the echoes arriving at times t1, t2, . . . and grouping sub-volumes that share a common round-trip echo arrival time;
• for each group of sub-volumes, identifying the sub-volume with the largest echo magnitude M;
• the echoes processed by a beamformer to form Q beams at one or more times tx;
• and,
• selecting a characterizing beam with beam index i which contains the sub-volume with the largest magnitude (Mtx,i) at one or more times tx;
• wherein data associated with the characterizing beams are used as a compressed characterization of the ensonified volume.