LONG BASELINE TRACKING SYSTEM

Abstract

A method for reliably locating the position of a submerged submarine with spect to a surface ship. A multiple number of transponders are placed at known locations near the sea floor, in the area of the ship and the submarine. One transponder has a dual function both as a response transponder and as a relay transponder. The other transponders have a single function as response transponders. Elapsed times between transmission of a first acoustic transmission pulse from the ship and receptions of first acoustic response pulses coming from the transponders, are measured at the ship. Elapsed times between transmission of a second acoustic pulse from the ship, its relay through the relay transponder, a response to the relayed signal by the submarine and then responses to the submarine's response pulse by the transponders, are also measured at the ship. These elapsed times are used to determine distances between the ship and the transponders, and distances between the transponders and the submarine. The location of the ship and the location of the submarine, with respect to the transponders, are determined from the distances.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1REGINALD CYR