Patent US3924236A successfully refreshed from Google Patents.
US3924236A
Expired / Lapsed
US
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Surveillance radar with synthetic array scan for improved angle determination
Assignee: International Standard Electric Corp
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Filing: 1974-11-25
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Granted: 1975-12-02
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Expires: 1994-11-25
Abstract
Abstract A synthetic aperture radio direction finding device having means for pulse illuminating objects within an angular sector of interest and a receiving array, each element of which has an independent output, for receiving echo pulses; a delay line with a number of taps equal to the number of said array elements, each tap receiving one element output after discrete mixing for each element against a common offset frequency. A bank of narrow band filters receives the delay line output and provides an output from a discrete one of said filters as a function of the angle of a reflecting object within the angular sector of interest.
Inventors
- 👤 Charles William Earp
- 👤 Carl Peter Sandbank
- 👤 Frances Giles Overbury
- 👤 Paul Barton
- 👤 Peter Kenneth Blair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:17
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/46; G01S3/48
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
184 words
Radio direction finding equipment for deriving angle information in respect to the position of a mobile craft from radio frequency pulses received from the craft, comprising: receiving antenna means responsive to each of said radio frequency pulses to produce a series of n simultaneous signals each of the same duration and frequency as the received pulse but with a phase differential between successive signals of said series which is a function of the angle subtended by the craft with respect to said antenna means; means for transferring said phase differential to a series of n simultaneous beat signals each of the same duration as said received pulse and at a frequency which is integrally related to the reciprocal of the duration of each received pulse; means responsive to said series of n beat signals to deliver an output signal of duration n times the duration of said received pulse and having a peak spectral content at a frequency which is shifted from said beat frequency by an amount indicative of said angle; and means responsive to said output signal to discretely determine said angle.
Claim 2
Dependent Claim
184 words
Radio direction finding equipment for deriving angle information in respect to the position of a mobile craft from radio frequency pulses received from the craft, comprising: receiving antenna means responsive to each of said radio frequency pulses to produce a series of n simultaneous signals each of the same duration and frequency as the received pulse but with a phase differential between successive signals of said series which is a function of the angle subtended by the craft with respect to said antenna means; means for transferring said phase differential to a series of n simultaneous beat signals each of the same duration as said received pulse and at a frequency which is integrally related to the reciprocal of the duration of each received pulse; means responsive to said series of n beat signals to deliver an output signal of duration n times the duration of said received pulse and having a peak spectral content at a frequency which is shifted from said beat frequency by an amount indicative of said angle; and means responsive to said output signal to discretely determine said angle.
Claim 3
Dependent Claim
21 words
Apparatus according to claim 1 in which said antenna means comprises at least onE linear array of n spaced antenna elements.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 2 in which said antenna means comprises two linear arrays normal to one another and each comprising n spaced antenna elements.
Claim 5
Dependent Claim
22 words
Apparatus according to claim 1 in which said antenna means comprises three mutually orthogonal linear arrays each comprising n spaced aerial elements.
Claim 6
Dependent Claim
18 words
Apparatus according to claim 1 in which said antenna means comprises an array of n2 spaced antenna elements.
Claim 7
Dependent Claim
73 words
Apparatus according to claim 2 in which said means for transfering comprises, for each of said antenna means, n mixers each having as one input a different one of said n simultaneous signals corresponding to a discrete element of said array, and as another input a radio frequency offset from the pulse radio frequency, with the offset frequency being integrally related to the reciprocal of the duration of each said radio frequency pulses.
Claim 8
Dependent Claim
55 words
Apparatus according to claim 2 in which said means responsive to said beat signals comprises a delay line having n input taps, with a delay time between adjacent taps equal to the duration of each of said radio frequency pulses, successive ones of said taps having as input corresponding successive ones of said beat signals.
Claim 9
Dependent Claim
55 words
Apparatus according to claim 2 in which said means responsive to said output signal comprises a plurality of narrow band filters each centered on a different frequency within the range of said output signal, the output of each of said filters corresponding to a discrete angle in respect to the position of said mobile craft.
Claim 10
Dependent Claim
201 words
Radio direction finding equipment for deriving angle information in respect to the position of a mobile craft from radio frequency pulses reflected from said craft, comprising: means for transmitting illuminating pulses covering the entire sector of interest within which said angle information is to be derived; a linear array of n spaced aerial elements for receiving said reflected pulses; n mixers each having one input connected to a different one of said antenna elements and another input connected to a common source of a radio frequency offset from the frequency of said pulse radio frequency, said offset frequency being integrally related to the reciprocal of the duration of each said radio frequency pulses, the output of each said mixer being said offset frequency; a delay line having n input taps, with a delay time between adjacent taps equal to the duration of each of said radio frequency pulses, successive ones of said input taps being connected to corresponding successive ones of said mixer outputs; and a plurality of narrow band filters each centered on a different frequency within the range of output frequencies of said delay line, said filters having their inputs all connected to the output of said delay line.
Claim 11
Dependent Claim
201 words
Radio direction finding equipment for deriving angle information in respect to the position of a mobile craft from radio frequency pulses reflected from said craft, comprising: means for transmitting illuminating pulses covering the entire sector of interest within which said angle information is to be derived; a linear array of n spaced aerial elements for receiving said reflected pulses; n mixers each having one input connected to a different one of said antenna elements and another input connected to a common source of a radio frequency offset from the frequency of said pulse radio frequency, said offset frequency being integrally related to the reciprocal of the duration of each said radio frequency pulses, the output of each said mixer being said offset frequency; a delay line having n input taps, with a delay time between adjacent taps equal to the duration of each of said radio frequency pulses, successive ones of said input taps being connected to corresponding successive ones of said mixer outputs; and a plurality of narrow band filters each centered on a different frequency within the range of output frequencies of said delay line, said filters having their inputs all connected to the output of said delay line.
References Cited (Backward Citations)
US3487408A
Cited
US3419845A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |