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Patent US3276554A successfully refreshed from Google Patents.
US3815134A
Expired / Lapsed
US
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Ground clutter reduction apparatus
Assignee: Westinghouse Electric Corp
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Filing: 1972-08-23
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Granted: 1974-06-04
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Expires: 1992-08-23
Abstract
Abstract A ''''scan down on receive'''' antenna system wherein time base switching of the receiver horn configuration is provided in a multifeed radar system for ground clutter reduction. After a radar pulse is transmitted, the receive beam is incrementally relocated so that the antenna is electrically made to ''''look up'''' for a short time corresponding to that portion of the interpulse period during which short and intermediate range targets are received and then ''''look down'''' for the remainder of the interpulse period during which long range targets are received. Such a system of feed switching includes an alternate receive gain path which receives clutter returns in a greatly reduced manner while continuing to receive target returns of interest, i.e., short and intermediate range targets.
Inventors
- 👤 C Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:37
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
227 words
Apparatus for enhancing radar target return signals with respect to clutter return signals, comprising in combination: a common transmit/receive antenna assembly for transmitting radio frequency energy generated by an associated transmitter and receiving reflected signals after said transmission, said antenna assembly including; a reflector and a plurality of RF transmit/receive feed elements selectively operated as a first set of elements providing a common transmit and a first receive gain path and as a second set of elements providing a second receive gain path, said first receive gain path having a response pattern displaced in a first elevation angle and said second receive gain path having a response pattern displaced in a second elevation angle higher than said first elevation angle and thereby providing an optimum gain path for reducing the amplitude of the clutter return signals; and control circuit means coupled to said plurality of RF transmit/receive feed elements being operable to cause said second receive gain path to be established after transmission for a predetermined intermediate time interval wherein relatively short and intermediate range return signals are received, and after said predetermined intermediate time interval and prior to a succeeding transmission rendering said second receive gain path inoperative and to establish said first receive gain path wherein relatively long range return signals are received and to maintain said last mentioned gain path for said succeeding transmission.
Claim 2
Dependent Claim
227 words
Apparatus for enhancing radar target return signals with respect to clutter return signals, comprising in combination: a common transmit/receive antenna assembly for transmitting radio frequency energy generated by an associated transmitter and receiving reflected signals after said transmission, said antenna assembly including; a reflector and a plurality of RF transmit/receive feed elements selectively operated as a first set of elements providing a common transmit and a first receive gain path and as a second set of elements providing a second receive gain path, said first receive gain path having a response pattern displaced in a first elevation angle and said second receive gain path having a response pattern displaced in a second elevation angle higher than said first elevation angle and thereby providing an optimum gain path for reducing the amplitude of the clutter return signals; and control circuit means coupled to said plurality of RF transmit/receive feed elements being operable to cause said second receive gain path to be established after transmission for a predetermined intermediate time interval wherein relatively short and intermediate range return signals are received, and after said predetermined intermediate time interval and prior to a succeeding transmission rendering said second receive gain path inoperative and to establish said first receive gain path wherein relatively long range return signals are received and to maintain said last mentioned gain path for said succeeding transmission.
Claim 3
Dependent Claim
65 words
The apparatus as defined by claim 1 wherein said transmitter transmits pulses having a predetermined interpulse period and wherein said control means comprises RF switch means coupled to said plurality of feed elements, said switch means being operable in a first position to provide said common transmit and said first receive gain path and in a second position to provide said second receive gain path.
Claim 4
Dependent Claim
40 words
The apparatus as defined by claim 2 wherein said common transmit and first receive gain path includes the first of said plurality of feed elements and said second receive gain path includes the last of said plurality of feed elements.
Claim 5
Dependent Claim
43 words
The apparatus as defined by claim 3 and additionally including an RF power divider coupled to the intermediate feed elements of said plurality of feed elements and said RF switch means selectively couples the first and last feed element to said power divider.
Claim 6
Dependent Claim
19 words
The apparatus as defined by claim 4 and additionally including synchronizer circuit means for operating said RF switch means.
Claim 7
Dependent Claim
54 words
The apparatus as defined by claim 5 wherein said synchronizer circuit means switches said feed elements to said second receive gain path at time intermediate t1 and t2 wherein t1 is the time at the end of a transmit pulse and t2 corresponds to the minimum range limitation of the radar target return signals.
Claim 8
Dependent Claim
68 words
The apparatus as defined by claim 1 wherein said plurality of feed elements is equal to m and said first and second receive gain paths are comprised of n elemenTs each wherein n is less than m and wherein said first receive gain path includes the first feed element of said m elements and said second receive gain path includes the last feed element of said m elements.
Claim 9
Dependent Claim
66 words
The apparatus as defined by claim 1 wherein said antenna assembly comprises a power divider and a dipole array of at least four elements coupled to said power divider wherein said intermediate elements are continuously coupled to said power divider and said first and last elements are intermittently coupled to said power divider in said first receive gain path and said second receive gain path respectively.
Claim 10
Dependent Claim
24 words
The apparatus as defined by claim 8 and additionally including RF switch means intercoupling said power divider and said first and last feed element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |