FM-CW radar for range and relative speed determination
First Claim
1. An FM-CW device for measuring distance and relative speed between a vehicle carrying said device and at least one other vehicle over a predetermined total range, said device including frequency sweep apparatus for transmitting a correspondingly frequency modulated radio frequency wave and for receiving reflected signals from at least said one other vehicle, comprising:
- first means including a first mixer responsive to said transmitted wave and to said reflected signals for generating a beat signal output containing frequency components representing distance and relative speed;
second means including a second mixer and a programmable local oscillator connected thereto, said second mixer being also responsive to said first means beat signal output, said second means further including means for programming said oscillator through a program of successive frequencies so as to successively examine a predetermined plurality of frequency increments within the frequency limits of said radio frequency modulated wave to provide a second mixer output;
third means including means synchronous with said frequency sweep apparatus and responsive to said second mixer output for producing an output identifying the distance between said vehicle and said other vehicle;
and fourth means responsive to said second mixer output of said second means and to the distance identifying output of said third means for generating a relative speed contemporaneous identifying signal by frequency evaluation of said second mixer output during the time of said distance identifying signal from said third means, to produce a relative speed identifying signal corresponding thereto.
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Accused Products
Abstract
An FM-CW vehicular distance and relative speed measuring device which compares instantaneous reflection signal frequency to the instantaneous FM-CW transmitted frequency to derive distance (range) and speed information. Searching means including a mixer, frequency programmer, and logic circuits evaluates a plurality of fractional range increments for signal presence and Doppler spectrum evaluation to determine relative velocity with sense. The FM-CW waveform is a sawtooth and means are included for blanking the sawtooth flyback.
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Citations
7 Claims
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1. An FM-CW device for measuring distance and relative speed between a vehicle carrying said device and at least one other vehicle over a predetermined total range, said device including frequency sweep apparatus for transmitting a correspondingly frequency modulated radio frequency wave and for receiving reflected signals from at least said one other vehicle, comprising:
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first means including a first mixer responsive to said transmitted wave and to said reflected signals for generating a beat signal output containing frequency components representing distance and relative speed; second means including a second mixer and a programmable local oscillator connected thereto, said second mixer being also responsive to said first means beat signal output, said second means further including means for programming said oscillator through a program of successive frequencies so as to successively examine a predetermined plurality of frequency increments within the frequency limits of said radio frequency modulated wave to provide a second mixer output; third means including means synchronous with said frequency sweep apparatus and responsive to said second mixer output for producing an output identifying the distance between said vehicle and said other vehicle; and fourth means responsive to said second mixer output of said second means and to the distance identifying output of said third means for generating a relative speed contemporaneous identifying signal by frequency evaluation of said second mixer output during the time of said distance identifying signal from said third means, to produce a relative speed identifying signal corresponding thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification