US3959641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital rangefinder correlation
Assignee: United States Department of the Army
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Filing: 1974-12-05
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Granted: 1976-05-25
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Expires: 1994-12-05
Abstract
Abstract Correlation in time of the extremely high frequency pulses which occur in tical rangefinders is accomplished by thresholding received returns at a low thresholding value, steering each received pulse to a plurality of up/down counters such that half of the time a counter is counting up and half of the time the counter is counting down. Dividing the up/down time of the counters in a digital format so as to provide a digital range readout from the up/down counters.
Inventors
- 👤 Walter E. Miller, Jr.
- 👤 Irvin E. Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:03
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; G06; G06F; G06F17/00; G06F17/10; G06F17/15
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
167 words
A system for detecting a time related signal in the presence of noise which occurs more often than the true signal occurs, comprising a receiver means connected to detect the signal and noise; first means dividing the length of time a single true signal can occur within into a plurality of equal parts; first through N detecting means connected to said first means and to said receiver means; said first detecting means being connected to sum up signal and noise occurrences in alternate one-half periods of time and to subtract from this sum the signal and noise occurrences in the remaining periods of time; the second detecting means being connected to sum up the noise and signal occurrences in alternate one-fourth periods of time and subtracting from this the noise and signal returns from the other periods of time; and connecting the third detector means through N detector means in the same manner as above in one-eighth, one-sixteenth . . . 1/N N periods of time respectively.
Claim 2
Independent Claim
167 words
A system for detecting a time related signal in the presence of noise which occurs more often than the true signal occurs, comprising a receiver means connected to detect the signal and noise; first means dividing the length of time a single true signal can occur within into a plurality of equal parts; first through N detecting means connected to said first means and to said receiver means; said first detecting means being connected to sum up signal and noise occurrences in alternate one-half periods of time and to subtract from this sum the signal and noise occurrences in the remaining periods of time; the second detecting means being connected to sum up the noise and signal occurrences in alternate one-fourth periods of time and subtracting from this the noise and signal returns from the other periods of time; and connecting the third detector means through N detector means in the same manner as above in one-eighth, one-sixteenth . . . 1/N N periods of time respectively.
Claim 3
Dependent Claim
33 words
A system as set forth in claim 1 wherein said system is cycled through a plurality of lengths of time wherein a true signal return can occur; and N is greater than 4.
Claim 4
Dependent Claim
25 words
A system as set forth in claim 2 wherein said detecting means are up/down counters; and said receiver means including a constant false alarm device.
Claim 5
Dependent Claim
191 words
A range finder system for detecting a time related signal in the presence of noise, said system employing digital means for correlating pulses comprising constant false alarm means connected to detect the signal and noise for generating fixed amplitude, fixed width pulses; a correlator comprising first means dividing the length of time a single true signal can occur within into a plurality of equal parts; first through N detecting means connected to said first means and to said false alarm means; said first detecting means being connected to sum up signal and noise occurrences in alternate one-half periods of time and to subtract from this sum the signal and noise occurrences in the remaining periods of time; the second detecting means being connected to sum up the noise and signal occurrences in alternate one-fourth periods of time and subtracting from this the noise and signal returns from the other periods of time; and connecting the third detector means through N detector means in the same manner as above in one-eighth, one-sixteenth . . . 1/N N periods of time respectively whereby the output of said correlator means is indicative of range.
Claim 6
Dependent Claim
191 words
A range finder system for detecting a time related signal in the presence of noise, said system employing digital means for correlating pulses comprising constant false alarm means connected to detect the signal and noise for generating fixed amplitude, fixed width pulses; a correlator comprising first means dividing the length of time a single true signal can occur within into a plurality of equal parts; first through N detecting means connected to said first means and to said false alarm means; said first detecting means being connected to sum up signal and noise occurrences in alternate one-half periods of time and to subtract from this sum the signal and noise occurrences in the remaining periods of time; the second detecting means being connected to sum up the noise and signal occurrences in alternate one-fourth periods of time and subtracting from this the noise and signal returns from the other periods of time; and connecting the third detector means through N detector means in the same manner as above in one-eighth, one-sixteenth . . . 1/N N periods of time respectively whereby the output of said correlator means is indicative of range.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |