Method and apparatus for rejecting rain clutter in a radar system
First Claim
1. A side-looking radar system for detecting presence of an object in the blind spot of a host vehicle upon which the radar system is mounted, wherein the object has an associated range and closing rate, comprising:
- (a) a radar transceiver for transmitting radar signals and for detecting reflected signals of the transmitted radar signals that are reflected off an object;
(b) a processor block, coupled to the transceiver, for controlling timing of the signals transmitted by the transceiver, and for processing the reflected signals received by the transceiver, wherein the processor block determines a presence, range and closing rate of the object from which the reflected signals are reflected, and wherein the processor block determines whether the object is within a predetermined detection zone, wherein the predetermined detection zone has a first bounded range that is greater than a minimum range of the radar system and a second bounded range that is less than a maximum range of the radar system, and wherein the processor block also determines whether the object remains within the detection zone for a predetermined minimum period of time; and
(c) an indicator, coupled to the processor block, the indicator receiving from the processor block an indication that the object remains within the detection zone for the predetermined minimum period of time, wherein the indicator warns an operator of the host vehicle that the object is present within the detection zone.
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Accused Products
Abstract
A method and apparatus for detecting the presence of objects in a vehicle operator'"'"'s blind spots. The apparatus comprises a side-facing Doppler radar system using continuous wave (CW) transmission with frequency modulation (FM) operation from a frequency modulation switching technique. The radar system determines the presence, range and closing rate of detected targets. The radar system detects targets even when operated in adverse weather conditions and will not generate false warnings due to rain clutter caused by wet roads and other wet surroundings. The radar system uses ranging techniques to reject false targets that are detected outside of a predetermined target detection zone. In accordance with the present invention, the radar system indicates that a target is detected if and only if any part of the target is within the detection zone and it: (1) remains in front of the antenna for at least TH1 seconds; (2) is at a range between Rangemin and Rangemax ; and (3) is moving faster than Closing-Speedmin relative to the antenna. By rejecting targets that are closer than Rangemin feet to the antenna, false alarms due to rain clutter are dramatically reduced. Also, by rejecting targets that are further than Rangemax feet from the antenna, the radar system reduces false alarms caused by wet foliage and other wet "non-road" surroundings. In one embodiment, the radar system uses a patch array antenna oriented into a diamond-shape configuration to effectively create a natural linear amplitude taper that aids in rejecting clutter caused by wet road surfaces.
55 Citations
40 Claims
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1. A side-looking radar system for detecting presence of an object in the blind spot of a host vehicle upon which the radar system is mounted, wherein the object has an associated range and closing rate, comprising:
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(a) a radar transceiver for transmitting radar signals and for detecting reflected signals of the transmitted radar signals that are reflected off an object; (b) a processor block, coupled to the transceiver, for controlling timing of the signals transmitted by the transceiver, and for processing the reflected signals received by the transceiver, wherein the processor block determines a presence, range and closing rate of the object from which the reflected signals are reflected, and wherein the processor block determines whether the object is within a predetermined detection zone, wherein the predetermined detection zone has a first bounded range that is greater than a minimum range of the radar system and a second bounded range that is less than a maximum range of the radar system, and wherein the processor block also determines whether the object remains within the detection zone for a predetermined minimum period of time; and (c) an indicator, coupled to the processor block, the indicator receiving from the processor block an indication that the object remains within the detection zone for the predetermined minimum period of time, wherein the indicator warns an operator of the host vehicle that the object is present within the detection zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A side-looking radar system for detecting objects in a blind spot of a host vehicle upon which the side-looking radar system is mounted, including:
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(a) a Doppler radar circuit for; (1) transmitting a modulated radar signal having a first and a second transmit frequency; (2) receiving a plurality of received reflections of the transmitted radar signal that are reflected from an object proximate the host vehicle, wherein each received reflection has an amount of power associated with and corresponding to a Doppler frequency of the received reflections; (3) detecting a Doppler frequency shift that has occurred between the transmitted radar signal and the reflected radar signal; and (4) determining the amount of power at each Doppler frequency of the received reflections; and (b) a controller, coupled to the Doppler radar circuit, for; (1) determining whether the object from which the received reflections are reflected is within a predetermined detection zone proximate the host vehicle, wherein the predetermined detection zone has a first bounded range that is greater than a minimum range of the radar system and a second bounded range that is less than a maximum range of the radar system; and (2) providing a warning to an operator of the host vehicle only if the object is detected within the detection zone, and only if the object remains within the detection zone for a predetermined minimum period of time. - View Dependent Claims (33, 34)
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35. A method for determining whether an object detected by a side-looking radar system is within a predetermined detection zone in a blind spot of a host vehicle upon which the radar system is mounted, including the steps of:
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(a) transmitting a modulated radar signal having a first and a second transmit frequency; (b) receiving reflections of the transmitted radar signal that are reflected from an object proximate the host vehicle, wherein the object has a range relative to the host vehicle; (c) determining the range based upon frequency characteristics of the reflected radar signals received in step (b); (d) determining whether the object is within a predetermined detection zone proximate the host vehicle, wherein the predetermined detection zone has a first bounded range that is greater than a minimum range of the radar system and a second bounded range that is less than a maximum range of the radar system; and (e) providing a warning to an operator of the host vehicle only if the object is detected within the detection zone, and only if the object remains within the detection zone for a predetermined minimum period of time. - View Dependent Claims (36, 37)
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38. A computer program residing on a computer-readable medium and executable on a general purpose computing device, wherein the program determines whether an object detected by a side-looking radar system is within a predetermined detection zone in a blind spot of a host vehicle upon which the radar system is mounted, comprising:
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(a) a first set of instructions for transmitting a modulated radar signal having a first and a second transmit frequency; (b) a second set of instructions for receiving reflections of the transmitted radar signal that are reflected from an object proximate the host vehicle, wherein the object has a range relative to the host vehicle; (c) a third set of instructions for determining the range based upon frequency characteristics of the reflected radar signals; (d) a fourth set of instructions for determining whether the object is within a predetermined detection zone proximate the host vehicle, and whether the object remains within the detection zone for a predetermined minimum period of time, wherein the predetermined detection zone has a first bounded range that is greater than a minimum range of the radar system and a second bounded range that is less than a maximum range of the radar system; and (e) a fifth set of instructions for providing a warning to an operator of the host vehicle only if the object is detected within the detection zone, and only if the object remains within the detection zone for the predetermined minimum period of time. - View Dependent Claims (39, 40)
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Specification