| 摘要 |
A system for locating a person including a mobile transmitter removably secured to the person and a portable monitoring unit carried by a user monitoring the location of the person. The mobile transmitter receives GPS ranging signals from GPS satellites. Each of the GPS ranging signals includes an offset proportional to the distance of the mobile transmitter from the respective GPS satellite broadcasting the GPS ranging signal. The GPS ranging signals, including the respective offsets, are transmitted to the portable monitoring unit. The portable monitoring unit comprises a GPS circuit which determines the location of the mobile transmitter based on the GPS ranging signals received by the mobile transmitter, and superimposes the location of the mobile transmitter on a map displayed on the portable monitoring unit.
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