US4439766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doppler radar having phase modulation of both transmitted and reflected return signals
Assignee: National Aeronautics and Space Administration
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Filing: 1981-05-22
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Granted: 1984-03-27
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Expires: 2001-05-22
Abstract
Abstract A microwave radar signal is generated (12) for transmission through an antenna (20). Before transmission, the signal is phase modulated (18) by 0° or 90° amounts during each alternate half-cycles of an intermediate frequency (IF) clock signal (26). After transmission and return, the signal is again phase modulated (18) the same amounts during each alternate half-cycles. The return phase modulated signal is mixed (24) with a leakage signal component of the microwave signal, leaving an IF doppler. The IF doppler signal may then be amplified (30), removing any requirement that direct current level signals be amplified and also removing the effect of detector noise from the doppler signal.
Inventors
- 👤 Herbert S. Kobayashi
- 👤 Paul W. Shores
- 👤 Patrick Rozas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:24
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/325
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
A doppler radar system for detecting the range rate of an object at close range comprising: (a) Local oscillator means for generating a radar signal; (b) a single antenna for transmitting and receiving radar signals; (c) means for phase modulating both the transmitted and returned signals with the same modulator and wherein said modulation occurs prior to any signal mixing; (d) means for mixing the returned signal with the local oscillator signal to form an intermediate frequency signal; (e) means for amplifying the intermediate frequency signal; and (f) means for demodulating the amplified intermediate frequency signal to form a doppler signal indicative of the range rate of the object.
Claim 2
Dependent Claim
109 words
A doppler radar system for detecting the range rate of an object at close range comprising: (a) Local oscillator means for generating a radar signal; (b) a single antenna for transmitting and receiving radar signals; (c) means for phase modulating both the transmitted and returned signals with the same modulator and wherein said modulation occurs prior to any signal mixing; (d) means for mixing the returned signal with the local oscillator signal to form an intermediate frequency signal; (e) means for amplifying the intermediate frequency signal; and (f) means for demodulating the amplified intermediate frequency signal to form a doppler signal indicative of the range rate of the object.
Claim 3
Dependent Claim
16 words
The radar system of claim 1, wherein said means for phase modulating comprises: phase shift means.
Claim 4
Dependent Claim
55 words
The radar system of claim 2, wherein said phase shift means operates on alternate half cycles of an established operating frequency and further comprises: (a) means for imposing no phase shift in one of the alternate half cycles; and (b) means for imposing a predetermined phase shift in the other of the alternate half cycles.
Claim 5
Dependent Claim
23 words
The radar system of claim 3, wherein said means for imposing a predetermined phase shift comprises: means for imposing a 90° phase shift.
Claim 6
Dependent Claim
27 words
The radar system of claim 3, wherein the established operating frequency is an intermediate frequency signal and further including: clock means for forming the intermediate frequency signal.
Claim 7
Dependent Claim
22 words
The radar system of claim 1, further including: means for displaying the demodulated signal to indicate the range rate of the object.
Claim 8
Independent Claim
95 words
A method of detecting the range rate of an object at close range comprising the steps of: (a) forming a radar signal with oscillator means; (b) transmitting and receiving said signals with the same antenna; (c) phase modulating both the transmitted and returned signals with the same modulator prior to any signal mixing; (d) mixing the returned signal with the oscillator signal to form an intermediate frequency signal; (e) amplifying the intermediate frequency signal; and (f) demodulating the amplified intermediate frequency signal to form a doppler signal indicative of the range rate of the object.
Claim 9
Independent Claim
95 words
A method of detecting the range rate of an object at close range comprising the steps of: (a) forming a radar signal with oscillator means; (b) transmitting and receiving said signals with the same antenna; (c) phase modulating both the transmitted and returned signals with the same modulator prior to any signal mixing; (d) mixing the returned signal with the oscillator signal to form an intermediate frequency signal; (e) amplifying the intermediate frequency signal; and (f) demodulating the amplified intermediate frequency signal to form a doppler signal indicative of the range rate of the object.
Claim 10
Dependent Claim
54 words
The method of claim 7, wherein said step of phase modulating is performed during alternate half cycles of an established operating frequency and comprises the steps of: (a) imposing no phase shift in one of the alternate half cycles; and (b) imposing a predetermined phase shift in the other of the alternate half cycles.
Claim 11
Dependent Claim
23 words
The method of claim 8, wherein said step of imposing a predetermined phase shift comprises the step of: imposing a 90° phase shift.
Claim 12
Dependent Claim
22 words
The method of claim 7, further including the step of: displaying the demodulated signal to indicate the range rate of the object.
References Cited (Backward Citations)
US2991471A
Cited
US3388398A
Cited
US3634860A
Cited
US3750171A
Cited
US3750172A
Cited
US4019185A
Cited
US4042925A
Cited
US4184154A
Cited
US4241347A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-27 | 1987-09-26 | 1988-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-27 | 1991-09-26 | 1992-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-27 | 1995-09-26 | 1996-03-27 | $7700.00 | Window Closed / Lapsed |