US3643256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secondary radar system
Assignee: AC Cossor Ltd
•
Filing: 1970-03-03
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Granted: 1972-02-15
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Expires: 1990-03-03
Abstract
Abstract The ground station of a secondary radar system is provided with improved means for preventing transponder replies being triggered via reflecting surfaces. A special pair of reflection suppression pulses are transmitted directively in fixed azimuthal directions only, the second pulse being the larger, thereby generating a suppression gate in a transponder receiving these pulses. The transmission of these pulses is preferably made dependent on the azimuthal angle of the scanning aerial (FIG. 5).
Inventors
- 👤 Philip Collinson Owen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:46
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/762
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
99 words
A secondary radar system ground station comprising a directional aerial for scanning in azimuth, an omnidirectional aerial and transmitting means coupled to the aerials for transmitting an interrogation group of pulses comprising at least one pulse transmitted via the directional aerial followed by A pulse transmitted by the omnidirectional aerial, and the improvement comprising at least one additional directional aerial viewing a fixed azimuthal sector, the transmitting means being further coupled thereto and arranged to transmit two reflection suppression pulses in succession via the fixed directional aerial, the second of these pulses being larger in amplitude than the first.
Claim 2
Dependent Claim
99 words
A secondary radar system ground station comprising a directional aerial for scanning in azimuth, an omnidirectional aerial and transmitting means coupled to the aerials for transmitting an interrogation group of pulses comprising at least one pulse transmitted via the directional aerial followed by A pulse transmitted by the omnidirectional aerial, and the improvement comprising at least one additional directional aerial viewing a fixed azimuthal sector, the transmitting means being further coupled thereto and arranged to transmit two reflection suppression pulses in succession via the fixed directional aerial, the second of these pulses being larger in amplitude than the first.
Claim 3
Dependent Claim
26 words
A secondary radar system ground station according to claim 1, wherein at least the first reflection suppression pulse precedes the first pulse of the interrogation group.
Claim 4
Dependent Claim
26 words
A secondary radar system ground station according to claim 2, wherein the second reflection suppression pulse is coincident with the first pulse of the interrogation group.
Claim 5
Dependent Claim
27 words
A secondary radar system ground station according to claim 2, wherein the second reflection suppression pulse lies between the first and second pulses of the interrogation group.
Claim 6
Dependent Claim
23 words
A secondary radar system ground station according to claim 1, wherein both the suppression pulses precede the first pulse of the interrogation group.
Claim 7
Dependent Claim
48 words
A secondary radar system ground station according to claim 1, further comprising control means arranged to vary the timing of the suppression pulses relative to the interrogation group as a function of the azimuthal angle of the scanning aerial, without varying the interval between the two suppression pulses.
Claim 8
Dependent Claim
44 words
A secondary radar system ground station according to claim 1, further comprising switching means and a control unit therefor, whereby the two suppression pulses are transmitted selectively by the, or each, fixed directional aerial as a function of azimuthal angle of the scanning aerial.
Claim 9
Dependent Claim
39 words
A secondary radar system ground station according to claim 7, further comprising an adjustable attenuator responsive to the control unit to vary the amplitude of the two suppression pulses as a function of azimuthal angle of the scanning aerial.
References Cited (Backward Citations)
US2824301A
Cited
US3122737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |