US3594794A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar target detection device
Assignee: RTX Corp
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Filing: 1969-06-25
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Granted: 1971-07-20
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Expires: 1989-06-25
Abstract
Abstract Clutter discrimination is effected in a phase interferometer radar system by varying the transmitted frequency, detecting resultant fluctuations from the mean elevation angle of return within a large number of range intervals, extracting the average fluctuation over a small number of range intervals, determining those range intervals for which the instantaneous fluctuation is less than the average fluctuation, and correlating the range intervals determined over a plurality of transmitted pulses to select any range interval consistantly providing relatively smaller fluctuations in apparent elevation angle and hence containing some radar target. The selected range interval may further be correlated over a plurality of azimuthal scans to provide additional discrimination.
Inventors
- 👤 Howard S Halpern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:22
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/42; G01S13/44; G01S13/4454; G01S7/00; G01S7/02; G01S7/41; G01S7/414
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
81 words
A radar target detection device including in combination means including a phase interferometer radar system for providing a first signal in accordance with the instantaneous elevation angle of terrain along an azimuth line, a range-gated filter, means coupling the signal to the gated filter, first comparing means responsive to the first signal and to the gated filter for providing a second signal, and means responsive to a reduction in magnitude of the second signal for indicating the presence of a target.
Claim 2
Dependent Claim
81 words
A radar target detection device including in combination means including a phase interferometer radar system for providing a first signal in accordance with the instantaneous elevation angle of terrain along an azimuth line, a range-gated filter, means coupling the signal to the gated filter, first comparing means responsive to the first signal and to the gated filter for providing a second signal, and means responsive to a reduction in magnitude of the second signal for indicating the presence of a target.
Claim 3
Dependent Claim
95 words
A device as in claim 1 in which the indicating means comprises means for rectifying the second signal, low-pass filtering means rEsponsive to the rectifying means, and second comparing means responsive to the rectifying means and to the low-pass filtering means. 3. A device as in claim 1 in which the indicating means comprises full-wave rectifying means providing a first output in response to the second signal, low-pass filtering means providing a second output in response to the rectifying means, and means for comparing the first output with a predetermined portion of the second output.
Claim 4
Dependent Claim
61 words
A device as in claim 1 in which the radar system transmits pulses at periodic intervals, wherein the indicating means comprises means providing a time delay equal to the period between successively transmitted pulses, means responsive to the second signal for exciting the time delay means, and a coincidence circuit responsive to the exciting means and to the time delay means.
Claim 5
Dependent Claim
74 words
A device as in claim 1 in which the radar system transmits pulses at periodic intervals, wherein the indicating means comprises a plurality of serially connected circuits each providing a time delay equal to the period between successively transmitted pulses, means responsive to the second signal for exciting the first of the serially connected time delay circuits, and a coincidence circuit responsive to each of the time delay circuits and to the exciting means.
Claim 6
Dependent Claim
124 words
A device as in claim 1 in which the radar system transmits pulses at periodic intervals, wherein the indicating means comprises means for correlating reductions in magnitude of the second signal over a plurality of transmitted pulses, and means responsive to the correlating means for indicating the presence of only those targets which consistently reduce the magnitude of the second signal. 7. A device as in claim 1 in which the radar system includes means for scanning in azimuth wherein the indicating means comprises means for correlating reductions in magnitude of the second signal over a plurality of azimuthal scans, and means responsive to the correlating means for indicating the presence of only those targets which consistently reduce the magnitude of the second signal.
Claim 7
Dependent Claim
91 words
A device as in claim 1 in which the radar system includes means for scanning in azimuth, the scanning means having a certain period, wherein the indicating means comprises means providing a time delay slightly less than the period between successive azimuthal scans, means responsive to the second signal for providing output pulses, a control circuit comprising a pulse-stretching circuit connected in series with the time delay means, means coupling the output pulses to the control circuit, and a coincidence circuit responsive to the output pulses and to the control circuit.
Claim 8
Dependent Claim
157 words
A device as in claim 1 in which the radar system includes means for scanning in azimuth, the scanning means having a certain period, wherein the indicating means comprises means providing a first time delay slightly less than the period between successive azimuthal scans, means providing a second time delay substantially equal to twice the first time delay, means responsive to the second signal for providing output pulses, a first pulse-stretching circuit, a second pulse-stretching circuit producing a pulse of somewhat less than twice the duration of that provided by the first stretching circuit, a first control circuit including the first stretching circuit connected in series with the first delay means, a second control circuit including the second stretching circuit connected in series with the second delay means, means coupling the output pulses to the first and second control circuits, and a coincidence circuit responsive to the output pulses and to the first and second control circuits.
Claim 9
Dependent Claim
26 words
A device as in claim 1 in which the radar system transmits pulses and includes means for periodically varying the carrier frequency of the transmitted pulses.
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) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |