Patent ID: 7650208

Claim:
An underwater navigation aid comprising: an underwater transceiver for transmitting and receiving signals underwater; a processing circuit coupled to said underwater transceiver and configured to: determine a direction to target from a current location of the navigation aid based on received signals from the target; establish a reference line extending through both the current location and a second remote location associated with a remote underwater device, said reference line forming the base of a reference triangle whose vertices correspond respectively to the current location, the remote location and the target location; compute a first included angle of said reference triangle between the reference line and a line extending through the current location and the target location; determine a first distance between the current location and the target location; determine a second distance between the current location and the remote location; compute a third distance from the remote location to the target location based on the first included angle and the first and second distances; and control the underwater transceiver to transmit the third distance to the remote underwater device to assist the remote underwater device in locating the target.