Shipping container security system
First Claim
1. A container security system, comprising:
- a micro-impulse radar positioned inside the container for transmitting microwave signals and receiving reflections of microwave signals; and
a detector operative during a predetermined time period for generating a first signal indicative of an average energy level of the reflections of the signals during the predetermined time period and for generating a second signal indicative of a Doppler shift occurring between the microwave signals and the reflections of the microwave signals during the predetermined time period.
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Accused Products
Abstract
A security system senses intrusions into a shipping container through the opening of doors, cutting an opening, or removing the doors from their hinges. Intrusion information is transmitted to a remote receiver without interrogation, thereby reducing power consumption. Sensing is accomplished by employing a range-gated micro-impulse radar (“RGR”) that generates microwave pulses that bounce around the interior of the container. The RGR includes a range gate that enables measuring reflected signals during the time gate period that is set for the time it takes a pulse to propagate a maximum distance within the container and reflect back. A direct current signal level is produced that represents the average reflected signal level within the container, and a Doppler shift measurement is made that represents motion inside the container. The signals are conveyed to the transmitter for conveyance to the remote receiver.
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Citations
25 Claims
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1. A container security system, comprising:
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a micro-impulse radar positioned inside the container for transmitting microwave signals and receiving reflections of microwave signals; and a detector operative during a predetermined time period for generating a first signal indicative of an average energy level of the reflections of the signals during the predetermined time period and for generating a second signal indicative of a Doppler shift occurring between the microwave signals and the reflections of the microwave signals during the predetermined time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of determining a security of a shipping container, comprising:
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transmitting microwave signals inside the container and receiving reflections of the microwave signals inside the container; generating a first signal indicative of an average energy level of the reflections of the signals; generating a second signal indicative of a Doppler shift occurring between the microwave signals and the reflections of the microwave signals; and processing at least one of the first and second signals to determine whether a container intrusion has occurred. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification