| 摘要 |
A apparatus and method for an operator to monitor the whereabouts of a subject, the apparatus comprising a portable remote unit connected to the subject, the remote unit including a remote unit power supply, a radio transmitter for sending a substantially constant remote unit radio signal, a radio receiver for receiving a base unit radio signal, a remote unit alarm, and a dye pack for releasing dye substantially responsive to submersion of the remote unit in water. The apparatus also includes a base unit in radio communication with the remote unit for enabling the operator to monitor the whereabouts of the remote unit, the base unit including a base unit power supply, a radio transmitter for sending the base unit radio signal, a radio receiver for receiving the substantially continuous remote unit radio signal, a distance estimator for substantially estimating the distance between the base unit and the remote unit, a base unit alarm responsive to the remote unit radio signal so that the base unit alarm is activated when the remote unit radio signal is altered, and a direction finding function for generally finding the direction from which the remote unit signal originates, relative to remote unit radio signal strength.
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