Monopulse azimuth radar system for automotive vehicle tracking
First Claim
1. A vehicular radar system for determining the deviation of at least one target about an automotive vehicle relative to a reference azimuth, comprising the combination of:
- (a) means for transmitting a transmission signal;
(b) means for sensing the transmission signal reflected from at least one target and received at two different locations as two different receive signals;
(c) means for converting each of the two different received signals to two different doppler signals by homodyning each received signal with the transmitted frequency;
(d) means responsive to the two different doppler signals for determining the sum of and the difference between the two different doppler signals; and
(e) means for comparing the sum and difference to determine the deviation of the target from the reference azimuth.
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Accused Products
Abstract
A monopulse vehicular radar system for tracking a target about an automotive vehicle senses a transmitted signal reflected back from the target and received at two different locations, determines the sum and the difference of the reflected signals sensed at the two locations, and compares the sum and difference to determine the deviation of the target from a reference azimuth. A source frequency provided by a Gunn diode is applied to and transmitted by a two-lobe monopulse antenna. The antenna lobes detect the reflected signals from the target by sensing them at the two different lobes. A hybrid junction provides sum and difference signals to mixers which homodyne the signals to produce sum and difference Doppler frequency signals using the source frequency. The Doppler frequency signals are amplified and then compared to determine the deviation of the target from the reference azimuth. The comparison process can be done digitally by converting the amplified frequency signals to digital signals which are then processed in a digital signal processor, or the comparison may be done in analog fashion using a phase/quotient detector. The range or distance of the target is determined by shifting the source frequency between two frequencies during transmission and frequency shifting the sum and difference Doppler frequency signals in similar fashion following reception by the antenna.
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Citations
20 Claims
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1. A vehicular radar system for determining the deviation of at least one target about an automotive vehicle relative to a reference azimuth, comprising the combination of:
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(a) means for transmitting a transmission signal; (b) means for sensing the transmission signal reflected from at least one target and received at two different locations as two different receive signals; (c) means for converting each of the two different received signals to two different doppler signals by homodyning each received signal with the transmitted frequency; (d) means responsive to the two different doppler signals for determining the sum of and the difference between the two different doppler signals; and (e) means for comparing the sum and difference to determine the deviation of the target from the reference azimuth. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A vehicular radar system for determining the deviation of a target about an automotive vehicle relative to a reference azimuth, comprising the combination of:
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(a) at least one mixer having a source frequency provided thereto; (b) antenna means for transmitting and receiving signals; (c) junction means for coupling the mixers to the antenna means to provide the source frequency to the antenna means for transmission therefrom as a transmission signal; (d) the antenna means including means for detecting the transmission signal reflected from the target and received at two different locations and coupled to the junction to provide the sum of and the difference between the transmission signal detected by the means for detecting at the two different locations; and (e) means for comparing the sum and the difference to determine the deviation of the target from the reference azimuth, wherein the mixers are responsive to the junction means to homodyne the sum and difference in accordance with the source frequency to produce sum and difference doppler signals. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A vehicular radar system for tracking a target about an automotive vehicle, comprising the combination of:
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(a) a multi-lobe monopulse antenna; (b) a junction coupled to the antenna and having at least a sum port and a difference port; (c) mixer means, coupled to the sum and difference ports of the junction and including a source frequency generator, for providing a transmission signal to the antenna through the sum port of the junction, the mixer means being operative to mix sum and difference signals at the sum and difference ports of the junction with the source frequency to produce a sum frequency signal and a difference frequency signal; (d) first and second data switches coupled to receive the sum frequency signal and the difference frequency signal; (e) a first, second, third and fourth filter; (f) an analog-to-digital converter coupled to the first data switch through the first and second filters and coupled to the second data switch through the third and fourth filters; (g) a timing generator for providing switch timing signals to the first and second data switches and timing clock signals to the analog-to-digital converter; (h) an analog-to-digital data conditioner coupled to the analog-to-digital converter; and (i) a line driver coupled to the data conditioner.
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18. A vehicular radar system for tracking a target about an automotive vehicle, comprising the combination of:
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(a) a dual lobe monopulse antenna; (b) a junction coupled to the antenna and having a sum port and a difference port; (c) a mixer coupled to the sum and difference ports of the junction and including a source frequency generator for providing a transmission signal to the antenna through the sum port of the junction, the mixer being operative to mix sum and difference signals at the sum and difference ports of the junction with the source frequency to produce a sum frequency signal and a difference frequency signal; (d) first and second data switches coupled to receive the sum frequency signal and the difference frequency signal; (e) a first, second, third and fourth filter; (f) first and second analog-to-digital converters, the first converter being coupled to the first data switch through first and second filters and the second converter being coupled to the second data switch through third and fourth filters; (g) a timing generator for providing switch timing signals to the first and second data switches and timing clock signals to the first and second analog-to-digital converters; (h) an analog-to-digital data conditioner coupled to the first and second analog-to-digital converter; and (i) a line driver coupled to the data conditioner. - View Dependent Claims (19, 20)
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Specification