Short range, ultra-wideband radar with high resolution swept range gate
First Claim
1. An apparatus for detecting a characteristic of objects within a field, comprising:
- a transmitter, including a shielded transmit cavity and a transmit antenna within the shielded transmit cavity, which transmits a sequence of electromagnetic pulses in response to a transmit timing signal;
a receiver, including a shielded receive cavity adjacent to the transmit cavity and a receive antenna within the shielded receive cavity, and a differential sampler having a first input connected to the receive antenna and a second input connected to ground, which samples echoes from objects within the field of 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, the sample signal indicating a characteristic of objects within the field;
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 echoes such that time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays.
2 Assignments
0 Petitions
Accused Products
Abstract
A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control.
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Citations
76 Claims
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1. An apparatus for detecting a characteristic of objects within a field, comprising:
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a transmitter, including a shielded transmit cavity and a transmit antenna within the shielded transmit cavity, which transmits a sequence of electromagnetic pulses in response to a transmit timing signal; a receiver, including a shielded receive cavity adjacent to the transmit cavity and a receive antenna within the shielded receive cavity, and a differential sampler having a first input connected to the receive antenna and a second input connected to ground, which samples echoes from objects within the field of 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, the sample signal indicating a characteristic of objects within the field; 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 echoes such that time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A swept range gate radar for detecting characteristics of objects within a field, comprising:
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a transmitter, including a shielded transmit cavity and a transmit antenna within the shielded transmit cavity, which transmits a sequence of electromagnetic pulses from the transmit antenna into the field in response to a transmit timing signal; a receiver, including a shielded receive cavity adjacent the transmit cavity and a receive antenna within the shielded receive cavity, which samples echoes from objects in the field of 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 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 echoes 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 signal processor, coupled with the receiver, to indicate a characteristic of the object in response to the sample signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A swept range gate radar for detecting characteristics of objects within a range of less than 20 feet, comprising:
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a transmitter, including a shielded transmit cavity and a resistively loaded transmit antenna within the shielded transmit cavity, which transmits a sequence of radio frequency (RF) pulses from the transmit antenna into the field in response to a transmit timing signal having a transmit pulse repetition rate of greater than 1 megaHertz; a receiver, including a shielded receive cavity, a resistively loaded receive antenna within the shielded receive cavity, a first sampling gate coupled to the receive antenna, a second sampling gate coupled to ground and a differential amplifier having a first input coupled to the first sampling gate and a second input coupled to the second sampling gate, which samples echoes from objects in the field of the sequence of RF pulses with controlled timing in the first and second sampling gates, 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 echoes such that time between transmission of pulses in the sequence by the transmitter and sampling by the receiver sweeps over a range of delays in a sweep cycle such that echoes are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents the received echoes in equivalent time; and a signal processor, coupled with the receiver, to indicate a characteristic of objects in the range in response to the sample signal. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A method for detecting a characteristic of an object within a field, comprising:
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generating a transmit timing signal; switching a transistor coupled to an antenna to produce the sequence of pulses, the transistor switches an output node coupled to the antenna less than 9 volts in amplitude, and in less than one nanosecond on the antenna in response to the transmit timing signal, to transmit a sequence of electromagnetic pulses to the field with controlled timing at a pulse repetition rate; generating a receive timing signal; switching a transistor coupled to a sample gate in response to the receive timing signal, the transistor switching an output coupled to the sampling gate less than 9 volts in amplitude, and in less than one nanosecond on the sample gate in response to the receive timing signal, to sample echoes of the sequence of electromagnetic pulses after reflection by the object to produce samples with controlled timing, so that time between the transmitting of pulses in the sequence and the sampling of echoes sweeps repeatedly over a range of delays; and producing a signal in response to an accumulation of the samples in a capacitance during the range of delays, indicating the characteristic of the object. - View Dependent Claims (54, 55, 56)
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57. An apparatus for detecting a characteristic of objects within a field, comprising:
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a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal, the transmitter including a transistor coupled to the antenna, the transistor biased in a non-avalanche switching region, and supplying transmit pulses to the antenna; a receiver which samples echoes from objects within the field of the sequence of electromagnetic pulses with controlled timing, in response to a receive timing signal, and generates a sample signal in response to an accumulation of the samples, the sample signal indicating a characteristic of objects within the field, and a timing circuit which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, to cause the receiver to sample the echoes such that time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76)
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Specification