US 5,430,450 A · Method and apparatus for automatically dimming motor vehicle headlights using radar signal

Abstract

The intensity of the headlights of a motor vehicle are modulated in response to pulsed Doppler radar signals which are used to distinguish between moving vehicles and other objects. The radar signals scan an area generally in front of the host vehicle. Reflected radar signals are received and radar return signals representative thereof are generated. A time to frequency domain transform, preferably a fast Fourier transform, is performed on the radar return signals to produce radar frequency signals. An adaptive technique is used to identify portions of the radar frequency signals produced by reflections from significant objects. The Doppler effect is used to determine the velocity of detected objects to the host vehicle. Any difference between the relative velocity of a detected object and the velocity of the host vehicle indicates that the object is moving. The velocity of the host vehicle may be determined by a conventional speed sensor or by means of radar signals reflected from a stationary object. Distance between the vehicle and a moving object is determined from the travel time of radar signals reflected from the moving object. The headlights of the host vehicle are modulated when a moving object is a predetermined distance from the host vehicle.

Claims20

Dependent claims

A method for modulating the intensity of at least one headlight of a motor vehicle, said at least one headlight being capable of operating in at least a high beam mode and a low beam mode, said method comprising the steps of:

transmitting a radar signal in a plurality of pulses;
receiving reflections of said radar signal;
determining a time between transmitting said radar signal and receiving said reflections of said radar signal;
generating a radar return signal indicative of said reflected radar signal;
processing said radar return signal to determine from the phase shift of said reflected radar signal if any portion of said radar return signal was produced by reflection from an object moving relative to said vehicle;
determining a distance between said motor vehicle and said object moving relative to said vehicle based on said determined time;
and
modulating the intensity of said at least one headlight in response to detection of a moving object and said distance between said motor vehicle and said moving object.

5 more elements

A method for modulating the intensity of at least one headlight of a motor vehicle, said headlight being capable of operation in at least a high beam mode and a low beam mode, said method comprising the steps of:

transmitting a radar signal;
receiving reflections of said radar signal in a plurality of pulses;
generating a radar return signal in response to said reflected radar signal;
performing a time domain to frequency domain transform of said radar return signal to produce a radar frequency signal;
determining if any portion of said reflected radar signal was produced by said radar signal being reflected from a significant object;
determining velocity of said vehicle;
determining if any significant object is moving relative to said vehicle based on said velocity of said vehicle and said radar frequency signal;
determining if any moving object is within a predetermined distance from said vehicle based on said radar frequency signal;
and
modulating the intensity of said at least one headlight if any moving object is within said predetermined distance from said vehicle.

7 more elements

An apparatus for modulating the intensity of at least one headlight of a motor vehicle, said headlight being capable of operation in at least a high beam mode and a low beam mode, said apparatus comprising:

radar means for transmitting a radar signal in blocks of pulses, for receiving reflections of said radar signal and for generating a radar return signal indicative of said reflections of said radar signal;
processor means for controlling said radar means, for processing said radar return signal to determine from the phase shift of said reflected radar signal if said radar return signal was produced by reflections of said radar signal from objects which are moving relative to said vehicle, for processing said radar return signal to determine distances to said moving objects and for generating a modulate headlights signal in response to said moving objects and said distances to said moving objects;
and
modulator means for modulating the intensity of said at least one headlight in response to said modulate headlights signal.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for automatically dimming motor vehicle headlights using radar signal

Life of this patent

Method and apparatus for automatically dimming motor vehicle headlights using radar signal

Life of this patent

Abstract

Claims20