초록 ▼

A micropower transponder operates in conjunction with a constellation of low-to-medium Earth-orbiting communication satellites. The transponder is attached to a person, animal, or object. The location of a missing person, animal, or lost object is ascertained by locating the transponder associated w

A micropower transponder operates in conjunction with a constellation of low-to-medium Earth-orbiting communication satellites. The transponder is attached to a person, animal, or object. The location of a missing person, animal, or lost object is ascertained by locating the transponder associated with that person, animal, or object. The transponder may be hidden in the individual's hair, timepiece, jewelry, or article of clothing; may be swallowed by the individual; may be implanted under the individual's skin; or incorporated into an inconspicuous hand-held device such as a cellular telephone, pager, or calculator. The transponder includes a receiver for receiving an interrogation radio signal and a transmitter for transmitting a response radio signal. The transponder transmits the response radio signal in response to the interrogation radio signal if the interrogation radio signal includes a code matching the access code stored in the transponder. The Doppler shift in frequency of the response radio signal is measured and the Doppler shift is used to determine the location of the transponder.

대표청구항 ▼

[ What is claimed is:] [1.]1. 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 respons

[ What is claimed is:] [1.]1. 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.