US3581310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar systems
Assignee: FROWDS Ltd
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Filing: 1969-04-09
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Granted: 1971-05-25
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Expires: 1989-04-09
Abstract
Abstract A radar system in which a transmitter and a receiver are located at each of two different sites, the transmitters being operated at different frequencies and some of the power of each transmitter serving as a local oscillator for the receiver which is located on the same site and which receives signals from the other transmitter to provide an intermediate frequency output, the two intermediate frequency outputs being mixed to provide a signal dependent only upon the rate of change of the total path length between the two sites via a target.
Inventors
- 👤 Trevor Buckley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:13
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/42
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
126 words
A radar system comprising first and second transmitters located at first and second sites, the transmitters being operable at first and second frequencies respectively, receivers located at said first and second sites for receiving transmission at said second and first frequencies respectively, means feeding some of the power of said first transmitter to the receiver at the first site to thereby produce a first intermediate frequency output, means feeding some of the power of said second transmitter to the receiver at the second site to thereby produce a second intermediate frequency output, and means for mixing said first and second intermediate frequency outputs to thereby produce a signal dependent upon the rate of change of the total path length between the two sites via a target.
Claim 2
Dependent Claim
126 words
A radar system comprising first and second transmitters located at first and second sites, the transmitters being operable at first and second frequencies respectively, receivers located at said first and second sites for receiving transmission at said second and first frequencies respectively, means feeding some of the power of said first transmitter to the receiver at the first site to thereby produce a first intermediate frequency output, means feeding some of the power of said second transmitter to the receiver at the second site to thereby produce a second intermediate frequency output, and means for mixing said first and second intermediate frequency outputs to thereby produce a signal dependent upon the rate of change of the total path length between the two sites via a target.
Claim 3
Dependent Claim
32 words
A system according to claim 1, wherein the operating frequency of the transmitter at one of the sites is controlled with the aid of a frequency discriminator centered at the intermediate frequency.
Claim 4
Dependent Claim
99 words
A system according to claim 1, wherein the frequencies of both transmitters are arranged to be controlled by a common oscillator whose frequency is a submultiple of the operating frequency of the first transmitter, which includes means for multiplying the output frequency of the common oscillator to obtain the operating frequency of the first transmitter, means for mixing the output of the common oscillator with the output of a further oscillator whose frequency is submultiple of the said intermediate frequency, and means for multiplying the output of the mixing means to obtain the operating frequency of the second transmitter.
Claim 5
Dependent Claim
27 words
A system as claimed in claim 1, wherein the transmitter and receiver at each site have a common antenna and suitable means are provided for achieving duplexing.
Claim 6
Dependent Claim
13 words
A system as claimed in claim 4 wherein duplexing is achieved using polarization.
References Cited (Backward Citations)
US3471845A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |