Precision short-range pulse-echo systems with automatic pulse detectors
First Claim
1. A precision pulse-echo ranging apparatus comprising:
- a transmit antenna;
a transmitter connected to the transmit antenna;
a transmit reference antenna collocated with the transmit antenna;
a transmit reference equivalent time (ET) sampler connected to the transmit reference antenna;
a receive antenna;
a receive equivalent time (ET) sampler connected to the receive antenna;
pulse detectors responsive to the transmit reference ET sampler and the receive ET sampler outputs;
a first gate pulse generator connected to a first pulse detector to gate off the first pulse detector after a defined delay interval following pulse detection;
a second gate pulse detector connected to a second pulse detector to enable the second pulse detector after a defined delay interval following pulse detection from the first pulse detector;
circuitry responsive to the pulse detectors to produce an output indicating target range.
2 Assignments
0 Petitions
Accused Products
Abstract
An equivalent time pulse-echo radar or other pulse-echo system employs a transmit reference sampler collocated with the transmitter to provide a transmit reference pulse, which initiates a pulse width modulated (PWM) pulse. A receive sampler connected to a receive antenna provides an echo-detection pulse that terminates the PWM pulse, such that the width of the PWM pulse indicates target range. The transmit reference sampler and the receive sampler are driven from a common clock such that transmit-receive timing offset drift precisely cancels on a picosecond scale, thereby enabling sub-mm range accuracy with common, low-cost circuit elements. The radar further includes automatically referenced pulse detectors that are responsive to either the magnitude or the phase of the sampler outputs. The radar can be used for precision tank level measurements, robotics, or automotive ranging applications.
77 Citations
25 Claims
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1. A precision pulse-echo ranging apparatus comprising:
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a transmit antenna; a transmitter connected to the transmit antenna; a transmit reference antenna collocated with the transmit antenna; a transmit reference equivalent time (ET) sampler connected to the transmit reference antenna; a receive antenna; a receive equivalent time (ET) sampler connected to the receive antenna; pulse detectors responsive to the transmit reference ET sampler and the receive ET sampler outputs; a first gate pulse generator connected to a first pulse detector to gate off the first pulse detector after a defined delay interval following pulse detection; a second gate pulse detector connected to a second pulse detector to enable the second pulse detector after a defined delay interval following pulse detection from the first pulse detector; circuitry responsive to the pulse detectors to produce an output indicating target range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A precision pulse-echo ranging apparatus comprising:
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a transmit antenna; a transmitter connected to the transmit antenna; a transmit reference antenna collocated with the transmit antenna; a transmit reference sampler connected to the transmit reference antenna; a receive antenna; a receive sampler connected to the receive antenna; a transmit clock connected to the transmitter; a receive clock connected to both the transmit reference sampler and the receive sampler; a first envelope detector connected to the transmit reference sampler; a second envelope detector connected to the receive sampler; a first automatic threshold pulse detector connected to the first envelope detector; a second automatic threshold pulse detector connected to the second envelope detector; logic circuitry connected to the first and second automatic threshold pulse detectors. - View Dependent Claims (15)
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16. A precision pulse-echo ranging apparatus comprising:
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a transmit antenna; a transmitter connected to the transmit antenna; a transmit reference antenna collocated with the transmit antenna; a transmit reference sampler connected to the transmit reference antenna; a receive antenna; a receive sampler connected to the receive antenna; a transmit clock connected to the transmitter; a receive clock connected to both the transmit reference sampler and the receive sampler; a first automatic threshold pulse detector connected to the transmit reference sampler; a second automatic threshold pulse detector connected to the receive sampler; logic circuitry connected to the first and second automatic threshold pulse detectors. - View Dependent Claims (17)
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18. A method for detecting the phase of a sinusoidal burst in a sequence of bursts, comprising:
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detecting a peak voltage of a first sinusoidal burst; holding the detected peak voltage from the first sinusoidal burst until a second sinusoidal burst occurs; multiplying the detected peak voltage by a fraction α
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1.0 to produce a threshold voltage that falls between two lobes of the second sinusoidal burst;comparing the threshold voltage and the second sinusoidal burst to produce a detection pulse from a selected sinusoidal lobe. - View Dependent Claims (19, 20, 21)
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22. A method for precisely determining radar target range, comprising:
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determining an exact time of transmission with a transmit reference equivalent time sampler collocated with a transmit antenna; determining an exact time of reception with a receive equivalent time sampler; determining radar range from the difference in transmit reference and receive equivalent times.
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23. An apparatus for precisely determining radar target range, comprising:
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a means for determining an exact time of transmission with a transmit reference equivalent time sampler collocated with a transmit antenna; a means for determining an exact time of reception with a receive equivalent time sampler; a means for determining radar range from the difference in transmit reference and receive equivalent times. - View Dependent Claims (24, 25)
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Specification