US3821736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency diversity pulse doppler radar
Assignee: United States Department of the Navy
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Filing: 1962-10-05
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Granted: 1974-06-28
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Expires: 1982-10-05
Abstract
Abstract 4. A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, a plurality of mechanical phase shifters having their outputs connected to said second mixer, a first switch means connected to each of said mechanical phase shifters and to said local oscillator for selectively connecting said oscillator to one of said mechanical phase shifters, and a control means for driving each phase shifter at a continuously varying speed until a proper Doppler signal is detected by said second mixer and for driving each phase shifter at a speed equal to the frequency of the Doppler ambiguity produced by a corresponding transmitted frequency after a proper Doppler signal is detected by said second mixer.
Inventors
- 👤 J Kuck
- 👤 D Staake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:58
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/581; G01S13/66; G01S13/70
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
150 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of random signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, and phase shifting means connected between said local oscillator and said second mixer for modifying the frequency of the signal from said oscillator to said second mixer so as to compensate for ambiguities in said Doppler signal due to changes in transmitted frequency.
Claim 2
Dependent Claim
150 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of random signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, and phase shifting means connected between said local oscillator and said second mixer for modifying the frequency of the signal from said oscillator to said second mixer so as to compensate for ambiguities in said Doppler signal due to changes in transmitted frequency.
Claim 3
Dependent Claim
150 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of random signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, and phase shifting means connected between said local oscillator and said second mixer for modifying the frequency of the signal from said oscillator to said second mixer so as to compensate for ambiguities in said Doppler signal due to changes in transmitted frequency.
Claim 4
Dependent Claim
150 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of random signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, and phase shifting means connected between said local oscillator and said second mixer for modifying the frequency of the signal from said oscillator to said second mixer so as to compensate for ambiguities in said Doppler signal due to changes in transmitted frequency.
Claim 5
Dependent Claim
87 words
A frequency diversity pulse Doppler radar system as defined in claim 1 wherein said phase shifting means comprises a plurality of mechanical phase shifters having their outputs connected to said second mixer, a first switch means connected to each of said mechanical phase shifters and to said local oscillator for selectively connecting said oscillator to one of said mechanical phase shifters, and a control unit for driving each phase shifter at a speed equal to the frequency of the Doppler ambiguity produced by a corresponding transmitted frequency.
Claim 6
Dependent Claim
71 words
A frequency diversity pulse Doppler radar system as defined in claim 1 wherein said transmitting means comprises a plurality of fixed frequency sources each producing a signal which differs in frequency from the other source signals by a direct fixed ratio, a noise generator, and a second switch means connected to said source and said antenna for selectively connecting said sources to said directive antenna in response to said noise generator.
Claim 7
Dependent Claim
71 words
A frequency diversity pulse Doppler radar system as defined in claim 4 wherein said transmitting means comprises a plurality of fixed frequency sources each producing a signal which differs in frequency from the other source signals by a direct fixed ratio, a noise generator, and a second switch means connected to said sources and said antenna for selectively connecting said sources to said directive antenna in response to said noise generator.
Claim 8
Dependent Claim
45 words
A frequency diversity pulse Doppler radar system as defined in claim 5 wherein said mechanical phase shifters are geared to each othEr by the direct fixed ratio between corresponding transmitted frequencies and are driven as a unit by a motor controlled by said control means.
Claim 9
Dependent Claim
163 words
A frequency diversity pulse Doppler radar system as defined in claim 4 wherein said control means comprises a sawtooth voltage generator, a servo driver connected to said phase shifters for driving said phase shifters at a proper speed, a relay connected to said generator and said servo driver, a variable frequency generator connected to said servo driver for producing a variable frequency signal, a narrow band filter, a third mixer connected to said second mixer, said frequency generator and said filter for comparing the outputs of said second mixer and said variable frequency generator and applying the result to said filter, said filter having a predetermined frequency band such that it will pass only select signals from said third mixer, a detector and a discriminator connected to said filter, said detector being connected to said relay such that signals from said filter will cause said relay to disconnect said sawtooth generator from said servo driver and connect said servo driver to said discriminator.
Claim 10
Dependent Claim
213 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining and timing the reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, a first switch, a phase locked oscillator chain having the output of each oscillator connected to said first switch, an electronic phase shifting unit selectively connected to one of said phase locked oscillators and connected to the output of said local oscillator for shifting the phase of said local oscillator signal in response to the output of said phase locked oscillator, said phase shifting unit being connected to said second mixer, and a control unit for controlling said oscillator chain such that each oscillator in the chain generates a frequency which is equal to the frequency of the Doppler ambiguity produced by a corresponding transmitted frequency.
Claim 11
Dependent Claim
213 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining and timing the reference signal and a target echo signal to produce a carrier Doppler signal, a second mixer connected to said first mixer and said local oscillator for detecting the Doppler portion of said target echo signal, a first switch, a phase locked oscillator chain having the output of each oscillator connected to said first switch, an electronic phase shifting unit selectively connected to one of said phase locked oscillators and connected to the output of said local oscillator for shifting the phase of said local oscillator signal in response to the output of said phase locked oscillator, said phase shifting unit being connected to said second mixer, and a control unit for controlling said oscillator chain such that each oscillator in the chain generates a frequency which is equal to the frequency of the Doppler ambiguity produced by a corresponding transmitted frequency.
Claim 12
Dependent Claim
71 words
A frequency diversity pulse Doppler radar system as defined in claim 8 wherein said transmitting means comprises a plurality of fixed frequency sources each producing a signal which differs in frequency from the other source signals by a direct fixed ratio, a noise generator, and a second switch means connected to said sources and said antenna for selectively connecting said sources to said directive antenna in response to said noise generator.
Claim 13
Dependent Claim
132 words
A frequency diversity pulse Doppler radar system as defined in claim 9 wherein said phase locked oscillator chain comprises a plurality of variable frequency oscillators, a plurality of first mixers each corresponding to one of said variable frequency oscillators and connected to the output thereof, each of said variable frequency oscillators also being connected to the mixer corresponding to the preceding oscillator in the chain, a plurality of second mixers each corresponding to one of said oscillator first mixer combinations and having their outputs connected to the input of the oscillator subsequent to the one to which they correspond, said second mixers being controlled by said control unit such that the output of each oscillator differs in frequency from the preceding oscillator in the chain by the frequency of the control signal.
Claim 14
Dependent Claim
83 words
A frequency diversity pulse Doppler radar system as defined in claim 8 wherein said control unit comprises means for continuously varying the freqeuncy of each of the oscillators in the oscillator chain until a proper Doppler signal is detected by said second mixer and for fixing the output of each oscillator in the oscillator chain at a frequency equal to the frequency of the Doppler ambiguity produced by a corresponding transmitted frequency after a proper Doppler signal is detected by said second mixer.
Claim 15
Dependent Claim
165 words
A frequency diversity pulse Doppler radar system as defined in claim 11 wherein said control means comprises a sawtooth voltage generator, a servo driver connected to said phase shifters for driving said phase shifters at a proper speed, a relay connected to said generator and said servo driver, a variable frequency generator connected to said servo driver for producing a variable frequency signal, a narrow band filter, a third mixer connected to said second mixer and said frequency generator and said filter for comparing the outputs of said second mixer and said variable frequency generator and for applying the result to said filter, said filter having a predetermined frequency band such that it will pass only select signals from said third mixer, a detector and a discriminator connected to said filter, said detector being connected to said relay such that signals from said filter will cause said relay to disconnect said sawtooth generator from said servo driver and connect said servo driver to said discriminator.
Claim 16
Dependent Claim
154 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, detecting means connected to said first mixer and said local oscillator for detecting the Doppler portion of said echo signal, a variable frequency generator, a second mixing means connected to said detecting means and said second mixing means for mixing the output signals from said units, and means for varying the frequency of said generating means so that the output of said second mixing means is free of Doppler frequencies.
Claim 17
Dependent Claim
154 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, detecting means connected to said first mixer and said local oscillator for detecting the Doppler portion of said echo signal, a variable frequency generator, a second mixing means connected to said detecting means and said second mixing means for mixing the output signals from said units, and means for varying the frequency of said generating means so that the output of said second mixing means is free of Doppler frequencies.
Claim 18
Dependent Claim
71 words
A frequency diversity pulse Doppler radar system as defined in claim 13 wherein said transmitting means comprises a plurality of fixed frequency sources each producing a signal which differs in frequency from the other source signals by a direct fixed ratio, a noise generator, and a second switch means connected to said sources and said antenna for selectively connecting said sources to said directive antenna in response to said noise generator.
Claim 19
Dependent Claim
84 words
A frequency diversity pulse Doppler radar system as defined in claim 14 wherein said detecting means comprises a first pair of mixers for combining the output of said first mixer with sine and cosine components of said local oscillator output, said second mixing means comprises a second pair of mixers for combining the outputs of said first pair of mixers with sine and cosine components of the output of said variable frequency generator, and said variable frequency generator comprises a phase locked oscillator chain.
Claim 20
Dependent Claim
90 words
A frequency diversity pulse Doppler radar system as defined in claim 15 wherein said means for varying the frequency of said generating means comprises a pair of low pass filters, a pair of squarers, and an adder interconnected such that the output signals from said second pair of mixers are filtered, squared and then combined in said adder, a noise threshold detecting means, and means for comparing the output of said adder with the output of said threshold detecting means and for applying the result to said variable frequency generator.
Claim 21
Dependent Claim
132 words
A frequency diversity pulse Doppler radar system as defined in claim 16 wherein said phase locked oscillator chain comprises a plurality of variable frequency oscillators, a plurality of first mixers each corresponding to one of said variable frequency oscillators and connected to the output thereof, each of said variable frequency oscillators also being connected to the mixer corresponding to the preceding oscillator in the chain, a plurality of second mixers each corresponding to one of said oscillator first mixer combinations and having their outputs connected to the input of the oscillator subsequent to the one to which they correspond, said second mixers being controlled by said control unit such that the output of each oscillator differs in frequency from the preceding oscillator in the chain by the frequency of the control signal.
Claim 22
Dependent Claim
201 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, detecting means connected to said first mixer and said local oscillator for detecting the Doppler portion of said echo signal, a variable frequency generator, a second mixing means connected to said detecting means and said second mixing means for mixing the output signals from said units, a relay connected to said variable frequency generator, sweep generator means connected to said relay for driving said variable frequency generator through a range of frequencies, and means for detecting the presence of Doppler frequencies in the output of said second mixing means connected to said relay such that an output from said Doppler detecting means will be applied to said variable frequency generator in place of said sweep generator means.
Claim 23
Dependent Claim
201 words
A frequency diversity pulse Doppler radar system comprising a directive antenna, transmitting means for providing a plurality of signals of different fixed frequencies connected to said antenna so as to generate exploratory pulses of electromagnetic energy, a stable local oscillator, modulating means connected to said transmitting means and said local oscillator for providing a timing reference signal, a first mixer connected to said modulator and said antenna for combining said timing reference signal and a target echo signal to produce a carrier Doppler signal, detecting means connected to said first mixer and said local oscillator for detecting the Doppler portion of said echo signal, a variable frequency generator, a second mixing means connected to said detecting means and said second mixing means for mixing the output signals from said units, a relay connected to said variable frequency generator, sweep generator means connected to said relay for driving said variable frequency generator through a range of frequencies, and means for detecting the presence of Doppler frequencies in the output of said second mixing means connected to said relay such that an output from said Doppler detecting means will be applied to said variable frequency generator in place of said sweep generator means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |