Underwater acoustic array, communication and location system

Abstract

An underwater communication system comprises a plurality of network nodes for sending and receiving ultrasonic energy through water. In accordance with one aspect, each of the network nodes includes an array of two ultrasonic transducers positioned so as to define a line segment. Each node also includes a transceiver adapted to generate a code element, generate a data element, generate a modulation element, and combine the code element, the data element and the modulation element into an analog waveform. The system is further adapted to transmit the analog waveform through each of the ultrasonic transducers and receive the analog waveform generated by at least one of the network nodes.

1 . An underwater communication and location device, comprising:
 an array of at least two omni-directional or isotropic ultrasonic transducers;   a receiver arranged to:
 receive, with the array of transducers, an analog waveform generated by a transmitter; 
 determine location information of the transmitter; and 
 interpret a data element transmitted by the transmitter. 
   
     
     
         2 . The underwater communication and location device of  claim 1 , wherein the transmitter is adapted to:
 generate a pseudo-random code element;   generate the data element;   generate a modulation element;   combine the pseudo-random code element, the data element and the modulation element into the analog waveform; and   transmit, to the receiver, the analog waveform through one or more ultrasonic transducers.   
     
     
         3 . The underwater communication and location device of  claim 1 , wherein the data element is generated by:
 applying an error-correcting code to user text or other information to generate an error-corrected data stream;   interleaving the error-corrected data stream, in order to correct burst errors; and   pre-pending sync data to the error-corrected data stream.   
     
     
         4 . The underwater communication and location device of  claim 1 , wherein the transducers are substantially spherical or cylindrical in shape. 
     
     
         5 . The underwater communication and location device of  claim 1 , wherein the array includes at least four ultrasonic transducers positioned so as to be non-coplanar. 
     
     
         6 . The underwater communication and location device of  claim 5 , wherein the ultrasonic transducers define a substantially tetrahedral shape. 
     
     
         7 . The underwater communication and location device of  claim 1 , wherein the array includes at least three ultrasonic transducers positioned so as to be non-colinear. 
     
     
         8 . The underwater communication and location device of  claim 7 , wherein the ultrasonic transducers define a substantially equilateral triangle. 
     
     
         9 . The underwater communication and location device of  claim 1 , wherein the array includes two ultrasonic transducers defining a line segment. 
     
     
         10 . The underwater communication and location device of  claim 1 , wherein the size and weight of the device allows for easy portability by an unassisted diver. 
     
     
         11 . The underwater communication and location device of  claim 10 , wherein the device is incorporated into a dive computer. 
     
     
         12 . The underwater communication and location device of  claim 1 , wherein the device is arranged for coupling with a high pressure hose used for monitoring SCUBA tank pressure. 
     
     
         13 . The underwater communication and location device of  claim 1 , wherein the device is arranged to communicate via electrical cable with a dive computer. 
     
     
         14 . The underwater communication and location device of  claim 1 , wherein the device is arranged to communicate wirelessly with a dive computer. 
     
     
         15 . The underwater communication and location device of  claim 1 , wherein the device is arranged to communicate bi-directionally, from a position on a SCUBA tank of a diver via magnetic inductive coupling with a dive computer of the diver. 
     
     
         16 . The underwater communication and location device of  claim 1 , wherein the device is arranged to communicate bi-directionally with a dive computer through a local peer-to-peer network. 
     
     
         17 . The underwater communication and location device of  claim 16 , wherein the device is further arranged to communicate bi-directionally with additional underwater equipment through the local peer-to-peer network. 
     
     
         18 . The underwater communication and location device of  claim 16 , wherein the device is further arranged to communicate bi-directionally with one or more devices arranged for monitoring diver heart rate, diver respiration rate, diver body core temperature or some combination of these through the local peer-to-peer network. 
     
     
         19 . The underwater communication and location device of  claim 17 , wherein the device is further arranged to communicate bi-directionally with one or more devices arranged for monitoring SCUBA tank pressure or parameters related to functioning of a closed-circuit breathing apparatus through the local peer-to-peer network. 
     
     
         20 . The underwater communication and location device of  claim 1 , wherein the receiver further comprises:
 a data acquisition module;   a data processing module;   a find synchronization module; and   an align synchronization module.   
     
     
         21 . The underwater communication and location device of  claim 20 , wherein the find synchronization module and the align synchronization module comprise:
 a data accumulator   a cross-correlator;   a channel selector;   a frequency corrector; and   an equalization filter.   
     
     
         22 . An underwater communication network, comprising:
 a plurality of network nodes, each including:
 an array of at least two omni-directional or isotropic ultrasonic transducers; 
 a transmitter adapted to,
 generate a pseudo-random code element; 
 generate a data element; 
 generate a modulation element; 
 combine the pseudo-random code element, the data element and the modulation element into an analog waveform; 
 transmit the analog waveform through one or more ultrasonic transducers; 
 
 a receiver arranged to:
 receive, with the array of omni-directional or isotropic ultrasonic transducers, an analog waveform transmitted by another network node. 
 
   
     
     
         23 . The underwater communication and location system of  claim 22 , wherein the nodes are configured to use depth, other location information or both of these shared among the nodes in order to more accurately establish relative location of the nodes. 
     
     
         24 . The underwater communication and location devices of  claim 22 , wherein the nodes are configured to share text messages, diver status, other information or some combination of these with other nodes of the network. 
     
     
         25 . A local, peer-to-peer underwater communication network, comprising:
 a plurality of peer network nodes configured to communicate bi-directionally with one another, wherein the plurality of peer network nodes include underwater equipment.   
     
     
         26 . The local, peer-to-peer underwater communication network as set forth in  claim 25 , wherein the plurality of peer network nodes further include a dive computer. 
     
     
         27 . The local, peer-to-peer underwater communication network as set forth in  claim 26 , wherein the plurality of peer network nodes further include an underwater communication and location device comprising:
 an array of at least two omni-directional or isotropic ultrasonic transducers;   a receiver arranged to:
 receive, with the array of transducers, an analog waveform generated by a transmitter; 
 determine location information of the transmitter; and 
 interpret a data element transmitted by the transmitter. 
   
     
     
         28 . The local, peer-to-peer underwater communication network as set forth in  claim 27 , wherein the transmitter is adapted to:
 generate a pseudo-random code element;   generate the data element;   generate a modulation element;   combine the pseudo-random code element, the data element and the modulation element into the analog waveform; and   transmit, to the receiver, the analog waveform through one or more ultrasonic transducers.