Patent ID: 6317049
Filing Date: 2001-11-13
Classification: G01S,G08B

Abstract:
A method for locating a missing person, animal, or object, said method comprising the steps of:(a) providing a transponder having an access code that identifies said transponder, said transponder configured to receive an interrogation radio signal and transmit a response radio signal, said transponder transmitting said response radio signal in response to receiving said interrogation radio signal if said interrogation radio signal includes a code matching said access code;(b) determining said access code corresponding to said transponder;(c) transmitting said interrogation radio signal including said access code from a transmitter located aboard an Earth-orbiting satellite;(d) receiving said response radio signal;(e) measuring a Doppler shift in frequency of said response radio signal; and(f) calculating a position of said transponder based on said Doppler shift.