Patent ID: 6163503
Filing Date: 2000-12-19
Classification: G01S

Abstract:
A system for determining a position of an object that is underwater, comprising:a device situated on a first object for receiving and decoding positioning signals transmitted from an external source in order to determine a position of the first object;a first acoustic transponder situated on the first object;a second acoustic transponder secured to a second object whose position is to be determined,wherein the position of the second object is assumed to be the position of the first object when said second object is sufficiently close to the first object that communications sent by one of said first and second transponders is received by the other of said first and second transponders,wherein the assumed position is stored in a memory on at least the other of said first and second objects; andfurther comprising additional objects having additional transponders situated out of range of the first transponder, said additional transponders including additional devices for receiving and decoding positioning signals transmitted from an external source, wherein when said second transponder passes sufficiently close to one of said additional transponders such that communications sent by one of said additional and second transponders is received by the other of said additional and second transponders, said position of said additional transponder is assumed to be the position of the second object and said position is stored in said memory, thereby enabling the second object to be tracked as it passes by said first object and any of said additional objects.