US3723002A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rangefinders
Assignee: BAC AND BRITISH AEROSPACE
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Filing: 1971-12-07
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Granted: 1973-03-27
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Expires: 1991-12-07
Abstract
Abstract In a laser rangefinder a gating pulse is generated after each laser pulse emission and the time-positions of successive gating pulses in the intervals between laser pulses are progressively shifted and correspond to progressively changing ranges for reflected light pulses. When a signal corresponding to a reflected light pulse falls within the gating pulse period, the gated output is integrated and when the integrated value exceeds a threshold value the progressive alteration of the time positions of the gating pulses is halted.
Inventors
- 👤 F Everest
- 👤 R Albery
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:34
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; G01S17/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
168 words
A rangefinder comprising a laser arranged to emit a succession of light pulses, a detector for detecting the receipt of reflected laser light and generating a corresponding electric signal, scanning pulse-generating means for generating a series of electric pulses, one in each interval between laser pulses, the scanning pulse-generating means including timing means for progressively altering the time-position of the generated pulse within the interval between successive laser pulses so that the moments of occurrence of the generated pulses in the intervals correspond to progressively changing ranges for reflected light pulses, gating means responsive to the generated pulses to pass a signal representative of a reflected laser pulse only when a generated pulse is present, means integrating the output of the gating means, and means connected with the timing means and with the integrating means and responsive when the integrated value exceeds a threshold value to stop the progressive alteration of the time position of the generated pulse in the sense in which the said alteration was progressing.
Claim 2
Dependent Claim
168 words
A rangefinder comprising a laser arranged to emit a succession of light pulses, a detector for detecting the receipt of reflected laser light and generating a corresponding electric signal, scanning pulse-generating means for generating a series of electric pulses, one in each interval between laser pulses, the scanning pulse-generating means including timing means for progressively altering the time-position of the generated pulse within the interval between successive laser pulses so that the moments of occurrence of the generated pulses in the intervals correspond to progressively changing ranges for reflected light pulses, gating means responsive to the generated pulses to pass a signal representative of a reflected laser pulse only when a generated pulse is present, means integrating the output of the gating means, and means connected with the timing means and with the integrating means and responsive when the integrated value exceeds a threshold value to stop the progressive alteration of the time position of the generated pulse in the sense in which the said alteration was progressing.
Claim 3
Dependent Claim
23 words
A rangefinder in accordance with claim 1, including a D.C. restoring circuit connected between the output of the detector and the gating means.
Claim 4
Dependent Claim
28 words
A rangefinder in accordance with claim 2, in which the D.C. restoring circuit includes switching means whereby the said circuit is rendered inoperative during the said generated pulses.
Claim 5
Dependent Claim
72 words
A rangefinder In accordance with claim 1, in which the scanning pulse-generating means includes second timing means for progressively altering the time-position of the generated pulse within the interval between successive laser pulses, the second timing means altering the time-position in a sense opposite to the alteration provided by the first timing means, and switching means for rendering the said second timing means operative when the integrated value exceeds the threshold value.
Claim 6
Dependent Claim
82 words
A rangefinder in accordance with claim 1, in which the scanning pulse-generating means includes a first ramp generator generating a ramp waveform following each laser pulse and a second and slower ramp generator generating a ramp waveform which extends over a number of cycles of the first ramp generator waveform, and a comparator circuit connected to receive ramp signals from the two ramp generators and generating a pulse each time that the instantaneous levels of the two ramp waveforms are the same.
Claim 7
Dependent Claim
16 words
A rangefinder in accordance with claim 1, in which the laser is a gallium arsenide laser.
References Cited (Backward Citations)
US3630616A
Cited
US3648286A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |