US3916408A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar receiver having clutter and large signal reduction
Assignee: Raytheon Co
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Filing: 1974-01-18
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Granted: 1975-10-28
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Expires: 1994-01-18
Abstract
Abstract An improved radar receiver including coherent side-lobe cancellation in which a difference pattern is utilized in azimuth by the auxiliary antenna to reduce the clutter return signal on the auxiliary channel and to also cause the clutter signal to be decorrelated with the clutter received on the main antenna. The two effects of reducing the clutter return and the decorrelation considerably reduces the degradation in coherent side-lobe cancellation operation of jamming signals characteristically caused by clutter on the auxiliary channel over most of the surveillance volume. Also, by providing substantial attenuation of the large target return in the auxiliary channel by the null in the direction of the principle response of the main antenna, large target signal returns are unable to capture the coherent side-lobe canceller loops and inhibit the coherent cancellation of jamming signals.
Inventors
- 👤 Norol T Evans
- 👤 Richard F Hyneman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:17
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/2813; H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/2605; H01Q3/2611; H01Q3/2629
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
115 words
A coherent radar receiver system responsive to target signals and jamming signals comprising: main antenna means for receiving energy and having a predetermined lobe pattern along a reception axis; auxiliary antenna means for receiving energy and having a pattern with a difference pattern symmetry relative to the reception axis of said main antenna means, said difference antenna pattern being centered at a null axis substantially parallel to the reception axis of said predetermined lobe pattern so clutter signals received from opposite sides of said null axis are decorrelated relative to clutter received by said main antenna means; and coherent side lobe canceller means coupled to said main antenna means and to said auxiliary antenna means.
Claim 2
Dependent Claim
115 words
A coherent radar receiver system responsive to target signals and jamming signals comprising: main antenna means for receiving energy and having a predetermined lobe pattern along a reception axis; auxiliary antenna means for receiving energy and having a pattern with a difference pattern symmetry relative to the reception axis of said main antenna means, said difference antenna pattern being centered at a null axis substantially parallel to the reception axis of said predetermined lobe pattern so clutter signals received from opposite sides of said null axis are decorrelated relative to clutter received by said main antenna means; and coherent side lobe canceller means coupled to said main antenna means and to said auxiliary antenna means.
Claim 3
Dependent Claim
17 words
The receiver system of claim 1 in which said predetermined lobe pattern is a sum lobe pattern.
Claim 4
Dependent Claim
43 words
The receiver system of claim 2 in which said auxiliary antenna means is selected to develop a maximum gain pattern with peaks along the azimuth dimension that are less than the peak of a miximum gain pattern developed by said main antenna means.
Claim 5
Dependent Claim
21 words
The receiver system of claim 3 in which said auxiliary antenna means includes an antenna and a difference network coupled thereto.
Claim 6
Dependent Claim
91 words
A coherent radar receiver system responsive to target signals, jamming signals and clutter signals comprising: a main receiver channel including main antenna means having a relatively narrow sum antenna beam along the antenna axis; an auxiliary receiver channel including auxiliary antenna means having an axis substantially parallel and co-incident to the axis of said main antenna means and having a difference pattern substantially symmetrical and having a null on said axis; and a coherent side-lobe canceller circuit coupled to said main and to said auxiliary receiver channels to cancel jamming signals.
Claim 7
Dependent Claim
91 words
A coherent radar receiver system responsive to target signals, jamming signals and clutter signals comprising: a main receiver channel including main antenna means having a relatively narrow sum antenna beam along the antenna axis; an auxiliary receiver channel including auxiliary antenna means having an axis substantially parallel and co-incident to the axis of said main antenna means and having a difference pattern substantially symmetrical and having a null on said axis; and a coherent side-lobe canceller circuit coupled to said main and to said auxiliary receiver channels to cancel jamming signals.
Claim 8
Dependent Claim
20 words
The system of claim 5 in which said auxiliary antenna means includes an antenna and a difference network coupled thereto.
Claim 9
Dependent Claim
42 words
The system of claim 5 in which said auxiliary antenna means is selected to develop a maximum gain pattern with peaks along the azimuth dimension that are less than the peak of a maximum gain pattern developed by said main antenna means.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |