Patent US1463406A successfully refreshed from Google Patents.
US3750171A
Expired / Lapsed
US
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Diplexed multi-frequency cw doppler radar
Assignee: Bendix Corp
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Filing: 1970-09-24
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Granted: 1973-07-31
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Expires: 1990-09-24
Abstract
Abstract This invention relates to a diplexed multi-frequency CW radar for use in the measurement of range and relative velocities between two vehicles. The radiated signal is modulated so that several frequencies are transmitted on a time-sharing basis. Doppler signals resulting from the reception of energy reflected from a target are gated to produce two composite doppler signals. Range to the target is proportional to the phase angle between the composite doppler tones and range rate is proportional to the frequency of the composite signal. The composite doppler signal can be represented as the vectorial summation of two component signals. The phase relationship between the two composite signals establishes range for all target ranges. However, the composite vectors are reduced to zero at a preselected maximum range and become ambiguous beyond that range. This provides range cut-off for the system. Ambiguous signals existing because of reflections from targets beyond the maximum range are below the threshold level of the system, and therefore, are of no consequence to the system.
Inventors
- 👤 W Faris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:39
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/34; G01S13/348; G01S13/50
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
208 words
A homodyne doppler radar system for yielding range, range rate and approach-recede information relative to a target and said radar system comprising: a transmitter for transmitting signals; a receiver for receiving reflected signals; means for mixing said transmitted signals and said reflected signals for producing doppler signals; means for frequency modulating said transmitter so that at least two discrete frequencies are transmitted and at least two doppler signals are produced by said means for mixing; individual doppler channels for individually receiving each of said doppler signals; individual gate means associated with respective ones of said channels so that said channels are responsive to said means for mixing; said gate means being responsive to said means for modulating so that said doppler channels are sequentially switched on and off as said discrete frequencies are sequentially transmitted; doppler phase comparison means receiving said doppler signals and producing an output indicative of the range between said target and said systems; range rate indicative means for receiving either of said doppler signals and producing an output indicative of the relative velocities of said target and said systems; and approach-recede means for receiving said doppler signals and generating an output indicative of the opening or closing relationship of said target and said system;
Claim 2
Dependent Claim
208 words
A homodyne doppler radar system for yielding range, range rate and approach-recede information relative to a target and said radar system comprising: a transmitter for transmitting signals; a receiver for receiving reflected signals; means for mixing said transmitted signals and said reflected signals for producing doppler signals; means for frequency modulating said transmitter so that at least two discrete frequencies are transmitted and at least two doppler signals are produced by said means for mixing; individual doppler channels for individually receiving each of said doppler signals; individual gate means associated with respective ones of said channels so that said channels are responsive to said means for mixing; said gate means being responsive to said means for modulating so that said doppler channels are sequentially switched on and off as said discrete frequencies are sequentially transmitted; doppler phase comparison means receiving said doppler signals and producing an output indicative of the range between said target and said systems; range rate indicative means for receiving either of said doppler signals and producing an output indicative of the relative velocities of said target and said systems; and approach-recede means for receiving said doppler signals and generating an output indicative of the opening or closing relationship of said target and said system;
Claim 3
Dependent Claim
40 words
The system of claim 1 wherein signals at four discrete frequencies are sequentially transmitted, two of said frequencies cooperating to form one of said doppler signals and the other two frequencies cooperating to form the other of said doppler signals.
Claim 4
Dependent Claim
71 words
The system of claim 2 wherein said doppler phase comparison means receives said first and second compoSite signals so that said output indicative of range is proportional to the phase difference between said composite signals, a phase difference existing for all ranges between said system and said target but the amplitudes of said composite signals gradually becoming zero at a preselected range to provide a maximum range cut-off for said system.
Claim 5
Dependent Claim
112 words
The system of claim 1 wherein signals of four discrete frequencies are transmitted, the first and second of said frequencies alternately actuating the first and second of said doppler channels respectively, and the third and fourth of said frequencies alternately actuating the first and second of said doppler channels respectively, the first and third of said frequencies sequentially actuating said first channel and the second and fourth of said frequencies sequentially actuating said second channel so that the first and third of said frequencies cooperate in the production of a first composite doppler signal and the second and fourth of said frequencies cooperate in the production of a second composite doppler signal.
Claim 6
Dependent Claim
61 words
The system of claim 1 wherein signals at four discrete frequencies are transmitted on a sequentially timed basis so that said four frequencies are alternatively gated to said first and second doppler channels, the first and third of said doppler signals forming a first composite doppler signal, and the second and fourth of said dopplersignals forming a second composite doppler signal.
Claim 7
Dependent Claim
21 words
The system of claim 5 wherein said transmitter, said receiver and said means for mixing are provided by a Gunn diode.
Claim 8
Dependent Claim
149 words
A doppler radar system having range cut-off capability comprising: means for generating and transmitting signals at four discrete frequencies; means for receiving reflected signals, said reflected signals being individually mixed with said discrete frequencies to produce four component doppler signals; a first and a second composite doppler channel; gating means for gating two of said component doppler signals to said first doppler channel to form a first composite doppler signal, and for gating the other two of said component doppler signals to said second doppler channel to form a second composite doppler signal, the phase difference between said composite doppler signals being indicative of the range between said radar system and a target, and the amplitudes of said composite signals approaching zero as a 180* phase difference between said component signals is approached so that a maximum range for said system is defined by said two composite doppler signals.
Claim 9
Dependent Claim
149 words
A doppler radar system having range cut-off capability comprising: means for generating and transmitting signals at four discrete frequencies; means for receiving reflected signals, said reflected signals being individually mixed with said discrete frequencies to produce four component doppler signals; a first and a second composite doppler channel; gating means for gating two of said component doppler signals to said first doppler channel to form a first composite doppler signal, and for gating the other two of said component doppler signals to said second doppler channel to form a second composite doppler signal, the phase difference between said composite doppler signals being indicative of the range between said radar system and a target, and the amplitudes of said composite signals approaching zero as a 180* phase difference between said component signals is approached so that a maximum range for said system is defined by said two composite doppler signals.
Claim 10
Dependent Claim
38 words
The system of claim 7 wherein said four frequencies are defined as F1, F2, F3, and F4 and: F2 F1 + Delta F F4 F3 + Delta F F1 - F3 Delta F/2 F2 - F4 Delta F/2.
Claim 11
Dependent Claim
43 words
The system of claim 8 wherein said means for generating and transmitting includes a voltage sensitive element, and modulation means for producing a waveform for modulating said voltage sensitive element to cause the transmission of said four frequencies F1, F2, F3, and F4.
Claim 12
Dependent Claim
39 words
The system of claim 9 further including self-test signal generating means for generating a test signal, said test signal being coupled to said first and second doppler channels so that the proper functioning of said system is periodically tested.
Claim 13
Dependent Claim
18 words
The system of claim 10 wherein said test signal is coupled to said doppler channels through said transmitter.
Claim 14
Dependent Claim
55 words
The system of claim 9 further including threshold establishing means receiving an input from one of said gating means, said threshold establishing means yielding a target present indication when said gating means provides an input above a preselected level and a target absent indication when said gating means provides an input below said preselected level.
Claim 15
Dependent Claim
24 words
The system of claiM 12 wherein said voltage sensitive element is a varactor and said means for generating and transmitting includes a Gunn diode.
Claim 16
Dependent Claim
120 words
The system of claim 13 further including phase detection means for receiving said composite doppler frequencies from said first and second doppler channels for producing a signal proportional to the phase difference between said composite doppler signals, said proportional signal being indicative of the range between a target and said system; a frequency converter receiving either of said composite doppler signals and producing a range rate signal in response to said doppler signal; and signal comparison means for receiving said composite doppler signals and producing a polarity signal, one polarity of said signal comparator indicating that said target is advancing with respect to said systems and the other polarity indicating that said target is receding with respect to said system.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |