Electronic license plate apparatus and method
First Claim
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1. An apparatus for association with an object for providing a reflective return digital coded message in response to a signal from an interrogating radar, said apparatus comprising;
- means associated with the object for receiving the interrogating radar signal;
means coupled to said receiving means for transmitting the interrogating signal within said apparatus;
a plurality of coupling means positioned along said transmitting means for dividing off said transmitting means a portion of the received interrogating signal;
delay line means coupled to each said coupling means, each said delay line means being unique to all other said delay line means;
means coupled to each delay line means for selectively reflecting or absorbing each delayed signal passing through said respective delay line means; and
means for reradiating from said apparatus the uniquely delayed reflected pulses, thereby forming a digital word comprised of the reflected pulses, which reradiated digital word is time spaced from the interrogation radar signal and from any such interrogation radar signal reflected from said object.
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Abstract
Apparatus and method for conveying information from an object by delayed reflection of an interrogating ultra-high range resolution radar signal which is digitized into a series of programmable spaced pulses by an electronic license plate circuit. The electronic license plate includes a plurality of unique programmable delay lines connected through a coupler network to an antenna.
54 Citations
13 Claims
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1. An apparatus for association with an object for providing a reflective return digital coded message in response to a signal from an interrogating radar, said apparatus comprising;
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means associated with the object for receiving the interrogating radar signal; means coupled to said receiving means for transmitting the interrogating signal within said apparatus; a plurality of coupling means positioned along said transmitting means for dividing off said transmitting means a portion of the received interrogating signal; delay line means coupled to each said coupling means, each said delay line means being unique to all other said delay line means; means coupled to each delay line means for selectively reflecting or absorbing each delayed signal passing through said respective delay line means; and means for reradiating from said apparatus the uniquely delayed reflected pulses, thereby forming a digital word comprised of the reflected pulses, which reradiated digital word is time spaced from the interrogation radar signal and from any such interrogation radar signal reflected from said object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for providing a reflective return digital coded message from an electronic license plate (ELP) circuit at an object when interrogated by a transmitted radar signal, said method comprising the steps of:
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receiving the transmitted radar signal at the object by receiving means; transmitting the received radar signal from the receiving means within the ELP circuit; dividing portions of the received signal off the transmitting means to each of a plurality of unique delay lines; selectively programming each delay line to be either reflective or absorptive; and reradiating the reflected delay signal portions from the receiving means back toward the radar transmitter in the form of a digital word. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification