Multimission and multispectral sonar
A survey system including a transmitter, receiver, projector array and hydrophone array transmits and receives sound waves to perform one or more survey missions.
1. A sonar system for conducting a survey, the sonar system comprising:
a transceiver for connection to a plurality of projectors in a projector array and a plurality of hydrophones in a hydrophone array where the arrays are not arranged in plural rows and plural columns;
a transceiver transmitter and the projector array configured to project an elongated transmit beam that simultaneously ensonifies an entire swath;
a transceiver receiver and the hydrophone array configured to form elongated receive beams; and,
wherein operation of the sonar system includes a) consecutive transmissions that include a first transmission that forms a first transmit beam and a second transmission that forms a second transmit beam, b) the first transmit beam conveys at least a first signal in a first frequency band and the second transmit beam conveys at least a second signal in a second frequency band that does not overlap with the first frequency band, c) each of the first and second transmit beams intersected by multiple receive beams, and d) the receive beams transport echo signals from scattering centers ensonified by the transmit beams.
2. The sonar system of claim 1 wherein the first transmission and the second transmission are spaced apart by a temporal gap that is 10 percent or more of the duration of one of the signals.
3. The sonar system of claim 1 wherein a) the first transmission is followed by b) the transport of echo signals from scattering centers ensonified by the first transmit beam which is followed by c) the second transmission.
4. The sonar system of claim 1 wherein the first signal frequency band and the second signal frequency band are spaced apart such that the echo signals indicate frequency dependent characteristics of the scattering centers.
5. The sonar system of claim 1 wherein:
a first ping cycle includes a first ping which is the first transmission; and,
a second ping cycle includes a second ping which is the second transmission;
wherein a ping cycle includes a ping and reception of echoes from that ping.
6. The sonar system of claim 5 further comprising:
a third ping cycle includes a third ping which is a third transmission;
the third transmission follows the second transmission; and,
the third transmission results in a third transmit beam conveying a third signal in a third frequency band that does not overlap the first or the second frequency bands.
7. The sonar system of claim 6 wherein the second frequency band is higher in frequency than the first frequency band and the third frequency band is higher in frequency than the second frequency band.
8. The sonar system of claim 6 wherein the second ping cycle is between the first and third ping cycles, the end of the first ping cycle abutting the beginning of the second ping cycle and the beginning of the third ping cycle abutting the end of the second ping cycle.
9. The sonar system of claim 6 wherein the second ping cycle is between the first and third ping cycles, the end of the first ping cycle substantially abutting the beginning of the second ping cycle and the beginning of the third ping cycle substantially abutting the end of the second ping cycle.
10. The sonar system of claim 6 wherein:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time t 1 m of less than 10 percent of a time t 1 required to transmit the first ping; and,
the second and third ping cycles separated by the time t 1 m.
11. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time t 2 m of less than 10 percent of a time t 2 required to transmit the second ping; and,
the second and third ping cycles separated by the time t 2 m.
12. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time t 3 m of less than 10 percent of a time t 3 required to transmit the third ping; and,
the second and third ping cycles separated by the time t 3 m.
13. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time tsdm of less than 10 percent of a time tsd required to transmit the ping having shortest duration; and,
the second and third ping cycles separated by the time tsdm.
14. The sonar system of claim 6 , wherein the first ping is spaced apart in time from the second ping and the second ping is spaced apart in time from the third ping.
15. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time t 1 p of 10 percent or more of a time t 1 required to transmit the first ping; and,
the second and third ping cycles separated by the time t 1 p.
16. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles; and,
the first and second ping cycles separated by a time t 2 p of 10 percent or more of a time t 2 required to transmit the second ping; and,
the second and third ping cycles separated by the time t 2 p.
17. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time t 3 p of 10 percent or more of a time t 3 required to transmit the third ping; and,
the second and third ping cycles separated by the time t 3 p.
18. The sonar system of claim 6 further comprising:
the second ping cycle is between the first and third ping cycles;
the first and second ping cycles separated by a time tsdp of 10 percent or more of a time tsd required to transmit the ping having the shortest duration; and,
the second and third ping cycles separated by the time tsdp.
19. The sonar system of claim 1 wherein:
the first transmission is transmission of a first message in a first message cycle; and,
the second transmission is transmission of a second message in a second message cycle;
wherein a message cycle includes a transmitted message and reception of echoes from that message.
20. The sonar system of claim 19 wherein at least one of the first and second transmit beams conveys multiple signals.
21. The sonar system of claim 20 further comprising:
a third consecutive transmission of a third message resulting in a third transmit beam conveying at least a third signal in a third frequency band that does not overlap the first or the second frequency band;
the first, second, and third messages used in first, second, and third message cycles; and,
the second message cycle is between the first and third cycles, the end of the first message cycle abutting the beginning of the second message cycle and the beginning of the third message cycle abutting the end of the second message cycle.