| 摘要 |
Method and apparatus for providing security for a vehicle and for cargo transported on the vehicle. A location determination (LD) system determines vehicle location. A cargo unit carries a transceiver (or transmitter) that transmits a selected signal, either sua sponte or in response to receipt of a polling signal. The selected signal, if received by a receiver on the vehicle, is examined as to signal intensity, signal coding and/or time of receipt. If the received signal violates a selected condition, vehicle location is compared with an approved cargo destination. If the vehicle is not near a cargo destination, or if no selected signal is received at the receiver, an alarm signal is transmitted, which may include the vehicle location and/or the violated condition. If the LD system does not receive adequate LD signals to determine vehicle location, vehicle location coordinates are compared with a coordinate range for a signal obscuring region (SOR). Vehicle location within the SOR can be tracked using a supplemental LD system until the vehicle leaves the SOR. If LD signals are lost for too long, inside or outside an SOR, an alarm signal is transmitted. If vehicle location is outside a travel corridor, if the vehicle does not pass a waypoint, if vehicle velocity is below a low threshold for too long, or if vehicle velocity is above a high threshold, an alarm signal is transmitted. The LD system may be GPS, GLONASS, LORAN or other satellite- or ground-based system.
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