US3768097A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal data processor for a pulse coherent range-gated doppler radar system
Assignee: International Standard Electric Corp
•
Filing: 1971-12-29
•
Granted: 1973-10-23
•
Expires: 1991-12-29
Abstract
Abstract A target bearing angle refinement device for use in a radar set such as a coherent pulse Doppler radar. The radar phase detector output containing a Doppler modulation component is applied to range selector circuits which are narrow, range increment gating devices providing Doppler (MTI) filtering with restored range information. Target bearing width is determined as a target echo signal crosses an amplitude threshold (increasing and decreasing) by sampling a continuously encoded bearing description as the antenna rotates and differencing the beginning and ending values. A read-only memory is sampled to obtain a correction as a function of a target''s width in the bearing coordinate, and the correction is added algebraically to a ''''half-sum'''' of the beginning and ending bearing values.
Inventors
- 👤 B Ziegler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:28
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/64; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/292; G01S7/2923; G01S7/2925
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
230 words
A device for refining the accuracy of angular target data in a radar system having an angularly scanning antenna and received signal detection and processing means which have inherently asymmetrical signal detection characteristics in respect to the envelope of hits defining the target angular width, comprising: angle signal means for continuously defining the angular position of said antenna within the limits of angular scan of said radar system; hit sensing means for generating a pair of signals, including a first signal at a time indicative of the first hit exceeding a predetermined amplitude threshold and a second signal at a time indicative of the last signal exceeding said threshold, during each cycle of angular scan of said antenna; subtraction means responsive to said hit sensing means for determining the difference of said first and second signal and thereby producing an output which is a function of target bearing width; target center estimating means responsive to said hit sensing means for generating a bearing signal which is a half-sum of said first and second signals; means storing a plurality of bearing correction signals, said means being addressable by the output of said subtraction means for producing a bearing correction signal as a function of said subtraction means output; and means for adding said bearing correction signal to the output of said target center estimating means to produce a corrected bearing signal.
Claim 2
Independent Claim
230 words
A device for refining the accuracy of angular target data in a radar system having an angularly scanning antenna and received signal detection and processing means which have inherently asymmetrical signal detection characteristics in respect to the envelope of hits defining the target angular width, comprising: angle signal means for continuously defining the angular position of said antenna within the limits of angular scan of said radar system; hit sensing means for generating a pair of signals, including a first signal at a time indicative of the first hit exceeding a predetermined amplitude threshold and a second signal at a time indicative of the last signal exceeding said threshold, during each cycle of angular scan of said antenna; subtraction means responsive to said hit sensing means for determining the difference of said first and second signal and thereby producing an output which is a function of target bearing width; target center estimating means responsive to said hit sensing means for generating a bearing signal which is a half-sum of said first and second signals; means storing a plurality of bearing correction signals, said means being addressable by the output of said subtraction means for producing a bearing correction signal as a function of said subtraction means output; and means for adding said bearing correction signal to the output of said target center estimating means to produce a corrected bearing signal.
Claim 3
Dependent Claim
39 words
Apparatus according to claim 1 in which said angle signal, said first and second signals, the output of said subtraction means, said half-sum signal, said correction signals and said corrected bearing signal are all defined as being digital codes.
Claim 4
Dependent Claim
26 words
Apparatus according to claim 2 in which said received signal detection and processing means in said radar set includes a range selector arrangement wIth Doppler filters.
Claim 5
Dependent Claim
54 words
Apparatus according to claim 3 in which said radar is defined as a coherent pulse Doppler radar and said signal detection and processing means also includes a phase detector within said radar for providing a train of echo signals, which are amplitude modulated by Doppler frequencies to the extent they correspond to moving targets.
Claim 6
Dependent Claim
105 words
Apparatus according to claim 4 including amplifying and limiting means responsive to the outputs of said range selectors, comparator means responsive to the output of said limiting means, said comparator means including a signal threshold for developing a control signal as said limiter output exceeds said threshold corresponding to the leading edge of the envelope of hits on a corresponding target during said angular scan and another control signal corresponding to the trailing edge of said envelope of hits, and means for developing said first and second signals in digital form by sampling said angle signal at the time of occurrence of said control signals.
Claim 7
Dependent Claim
71 words
Apparatus according to claim 5 in which a memory responsive to said first and second signals is provided for storing said first and second signals after said second signal is generated until the first signal corresponding to the next angular scan cycle, thereby to provide time for operation of said subtraction means, said target center estimating means, and said bearing correction signal determination and application to produce said corrected bearing signal.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |