Time-of-flight radio location system
First Claim
1. An apparatus for measuring time-of-flight of an electromagnetic pulse, comprising:
- a transmitter which transmits a sequence of electro-magnetic pulses in response to a transmit timing signal;
a receiver which samples the sequence of electro-magnetic pulses with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples;
a timing circuit which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, the receive timing signal causing the receiver to sample the sequence of electro-magnetic pulses such that time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays; and
a sample detection circuit which in response to the sample signal and the timing circuit indicates a time-of-flight between the transmitter and the receiver of pulses in the sequence.
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Accused Products
Abstract
A bi-static radar configuration measures the direct time-of-flight of a transmitted RF pulse and is capable of measuring this time-of-flight with a jitter on the order of about one pico-second, or about 0.01 inch of free space distance for an electromagnetic pulse over a range of about one to ten feet. A transmitter transmits a sequence of electromagnetic pulses in response to a transmit timing signal, and a receiver samples the sequence of electromagnetic pulses with controlled timing in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the sequence of electromagnetic pulses such that the time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays. The receive timing signal sweeps over the range of delays in a sweep cycle such that pulses in the sequence are sampled at the pulse repetition rate, and with different delays in the range of delays to produce a sample signal representing magnitude of a received pulse in equivalent time. Automatic gain control circuitry in the receiver controls the magnitude of the equivalent time sample signal. A signal processor analyzes the sample signal to indicate the time-of-flight of the electromagnetic pulses in the sequence.
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Citations
31 Claims
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1. An apparatus for measuring time-of-flight of an electromagnetic pulse, comprising:
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a transmitter which transmits a sequence of electro-magnetic pulses in response to a transmit timing signal; a receiver which samples the sequence of electro-magnetic pulses with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples; a timing circuit which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, the receive timing signal causing the receiver to sample the sequence of electro-magnetic pulses such that time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays; and a sample detection circuit which in response to the sample signal and the timing circuit indicates a time-of-flight between the transmitter and the receiver of pulses in the sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for detecting position of an object, comprising:
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a transmitter, for placement on the object, which transmits a sequence of electro-magnetic pulses in response to a transmit timing signal; a receiver which samples the sequence of electro-magnetic pulses with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples; a timing circuit which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, the receive timing signal causing the receiver to sample the sequence of electro-magnetic pulses such that time between transmission of pulses in the sequence by the transmitter and sampling by the receiver sweeps over a range of delays; and a pulse detection circuit which in response to the sample signal and the timing circuit generates a pulse detect signal when the sample signal reaches a threshold during a sweep; and a signal processor, coupled with the pulse detection circuit, to indicate a position of the object in response to the pulse detect signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for detecting position of an object, comprising:
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a transmitter, for placement on the object, which transmits a sequence of microwave pulses in response to a transmit timing signal with a pulse repetition rate greater than about 1 megahertz; a receiver having an antenna, a sample gate coupled to the antenna, which samples which samples a signal on the antenna at the pulse repetition rate and with controlled timing in response to a receive timing signal, and an amplifier coupled to the sample gate including automatic gain control such that pulses in the sequence are sampled to generate an equivalent time sample signal; a timing circuit which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, the receive timing signal causing the receiver to sample the sequence of electro-magnetic pulses such that time between transmission of pulses in the sequence by the transmitter and sampling by the receiver sweeps over a range of delays varying by less than 20 nanoseconds in a sweep duration of greater than about 10 milliseconds; and a signal processor, coupled with the receiver, to indicate a position of the object within a range of less than 10 feet in response to the equivalent time sample signal. - View Dependent Claims (26, 27)
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28. A method for detecting position of an object at a range of less than 10 feet, comprising:
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mounting a transmitter on the object; transmitting from the transmitter a sequence of electromagnetic pulses; detecting time-of-flight of the electromagnetic pulses from the transmitter to a receiver by sampling the sequence of pulses with controlled timing to produce an equivalent time representation of a transmitted pulse at the receiver and processing the equivalent time signal to indicate the time-of-flight; and processing the time-of-flight to indicate position of the object. - View Dependent Claims (29, 30, 31)
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Specification