| 摘要 |
<p>A micropower transponder (100) operates in conjunction with a constellation of low-to-medium Earth-orbiting communication satellites (202). The transponder (100) is attached to a person, animal or object. The location of a missing person, animal or lost object is ascertained by locating the transponder (100) associated with that person, animal or object. The transponder (100) 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 handheld device such as a cellular telephone, paper, or calculator. The transponder (100) includes a receiver for receiving an interrogation signal in response to the interrogation radio signal if the interrogation radio signal includes a code matching the access code stored in the transponder (100). The Doppler shift in frequency of the response signal is measured and the Doppler shift is used to determine the location of the transponder (100).</p> |
