Patent US4404561A successfully refreshed from Google Patents.
US4404561A
Expired / Lapsed
US
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Radar system
Assignee: HOLLANDSE SIGNAALAPARATEN BV A FIRM OF NETHERLANDS
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Filing: 1980-02-13
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Granted: 1983-09-13
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Expires: 2000-02-13
Abstract
Abstract A radar system comprises an antenna including a reflector having two vertically mounted receiving elements and two receiving channels connected to the elements. The receiving elements form, in cooperation with the reflector, almost coinciding cosecant-square beamed patterns. A measuring circuit connected to the two receiving channels measures the phase difference between the signals received by the receiving elements. A transformation unit connected to the phase measuring circuit converts the phase difference to a signal representative of the elevation angle of the target.
Inventors
- 👤 Willem Mulder
- 👤 Gerrit Van Rooyen
- 👤 Johan M. C. Zwarts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:49
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/42; G01S13/44; G01S13/4454; G01S3/00; G01S3/02; G01S3/14; G01S3/46; G01S3/48
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
101 words
A radar system for determining the angle of elevation of a detected target, comprising: (a) an antenna including a reflector and two vertically mounted receiving elements for cooperating to form almost coinciding, substantially cosecant-squared beam patterns; (b) two receiving channels electrically-connected to the receiving elements for processing signals from the elements; (c) a phase measuring circuit electrically-connected to the receiving channels for measuring the phase difference Δφ between signals processed by the channels; and (d) a transformation unit electrically-connected to the phase measuring circuit for converting the phase difference into a signal representative of the elevation angle ε of the target.
Claim 2
Dependent Claim
101 words
A radar system for determining the angle of elevation of a detected target, comprising: (a) an antenna including a reflector and two vertically mounted receiving elements for cooperating to form almost coinciding, substantially cosecant-squared beam patterns; (b) two receiving channels electrically-connected to the receiving elements for processing signals from the elements; (c) a phase measuring circuit electrically-connected to the receiving channels for measuring the phase difference Δφ between signals processed by the channels; and (d) a transformation unit electrically-connected to the phase measuring circuit for converting the phase difference into a signal representative of the elevation angle ε of the target.
Claim 3
Dependent Claim
73 words
A radar system as in claim 1, wherein the phase measuring circuit comprises: (a) first and second quadrature phase detectors for detecting the signals processed by the receiving channels in two mutually perpendicular components I 1 , Q 1 and I 2 , Q 2 ; and (b) phase measuring means for determining the phase difference Δφ in accordance with the relationship Δφ=arctan I 1 /Q 1 -arctan I 2 /Q 2 .
Claim 4
Dependent Claim
43 words
A radar system as in claim 2, including a plurality of MTI filter circuits electrically-connected between the phase detectors and the phase measuring means for filtering respective ones of the components I 1 , Q 1 , I 2 , Q 2 .
Claim 5
Dependent Claim
36 words
A radar system as in claim 1, wherein the transformation unit comprises a pulse modulator for converting the phase difference Δφ into a pulse train in which the number of pulses represents the elevation angle ε.
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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |