Patent US3987442A successfully refreshed from Google Patents.
US3987442A
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Digital MTI radar system
Assignee: Raytheon Co
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Filing: 1974-06-24
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Granted: 1976-10-19
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Expires: 1994-06-24
Abstract
Abstract A digital MTI radar system is disclosed which is adapted to reject moving clutter returns and to pass, for detection and display, returns from moving targets. The radar system includes means for producing a series of complex digital words representative of the average moving clutter Doppler velocity at each one of a series of range cells. A canceller network is provided to modify the returns from a range sweep with the complex digital words and to combine such modified returns with the returns of a successive range sweep, thereby to effectuate the desired moving clutter rejection.
Inventors
- 👤 Willard W. McLeod, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:51
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/522; G01S13/524; G01S13/5244; G01S13/526
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
225 words
In a radar system wherein "in phase" and "quadrature" signals are produced for each one of a series of range sweeps, such signals being phase compared with a reference signal to produce a pair of signals and wherein such pair of signals is converted into a series of complex digital words, each one of such words corresponding to a different one of a number of range cells in each one of the series of sweeps, the improvement comprising: a. means for combining a portion of the series of complex digital words of one of the series of range sweeps with a portion of the series of complex digital words of another one of such range sweeps to produce a series of correction complex digital words, each one thereof being representative of the average Doppler velocity of returns at a different one of the range cells; b. canceller means including: means for modifying each one of the input complex digital words of one of the range sweeps with a corresponding one of the correction complex digital words to produce a series of modified complex digital words; and means for combining each one of the modified complex digital words with a different one of the input complex digital words of another one of the range sweeps to reject moving clutter returns and to pass moving target returns.
Claim 2
Dependent Claim
225 words
In a radar system wherein "in phase" and "quadrature" signals are produced for each one of a series of range sweeps, such signals being phase compared with a reference signal to produce a pair of signals and wherein such pair of signals is converted into a series of complex digital words, each one of such words corresponding to a different one of a number of range cells in each one of the series of sweeps, the improvement comprising: a. means for combining a portion of the series of complex digital words of one of the series of range sweeps with a portion of the series of complex digital words of another one of such range sweeps to produce a series of correction complex digital words, each one thereof being representative of the average Doppler velocity of returns at a different one of the range cells; b. canceller means including: means for modifying each one of the input complex digital words of one of the range sweeps with a corresponding one of the correction complex digital words to produce a series of modified complex digital words; and means for combining each one of the modified complex digital words with a different one of the input complex digital words of another one of the range sweeps to reject moving clutter returns and to pass moving target returns.
Claim 3
Dependent Claim
55 words
The improvement recited in claim 1 wherein the combining means includes for complex multiplying each one of the complex digital words of one of the range sweeps by the complex conjugate of corresponding ones of the series of complex digital words of another one of the range sweeps to form a series of product vectors.
Claim 4
Dependent Claim
21 words
The improvement recited in claim 2 wherein the combining means includes means for summing a predetermined number of the product vectors.
Claim 5
Dependent Claim
36 words
The improvement recited in claim 3 wherein the combining means includes means for dividing the summed product vectors by the magnitude of such summed vectors thereby forming one of the series of correction complex digital words.
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) | 1979-10-19 | 1980-04-19 | 1980-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-19 | 1984-04-19 | 1984-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-19 | 1988-04-19 | 1988-10-19 | $7700.00 | Window Closed / Lapsed |