Patent US3630616A successfully refreshed from Google Patents.
US3630616A
Expired / Lapsed
US
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Range finders
Assignee: BAC AND BRITISH AEROSPACE
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Filing: 1969-03-03
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Granted: 1971-12-28
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Expires: 1989-03-03
Abstract
Abstract In a laser range finder a short ramp voltage is generated after each laser pulse and a long sweep voltage has a progressive voltage variation extending over a number of cycles of the short ramp voltage. Each time that a short ramp voltage waveform crosses the instantaneous value of the long sweep voltage, two successive gating signals are generated. If a reflected laser pulse arrives within the total gating interval, the progressive variation of the sweep waveform is halted and the difference in signal in the successive gating interval is used to center the total gating interval on the reflected laser pulse. A DC clamp restores the DC level of the sweep voltage generator after each pair of gating signals.
Inventors
- 👤 Frank Geoffrey Everest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:52
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; G01S17/18
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
242 words
A laser range finder comprising: a laser for emitting a succession of light pulses; a ramp generator producing a ramp voltage following the transmission of each laser pulse; a rangesweep generator producing a sweep signal having a progressive voltage variation extending over a number of ramp voltage cycles; a gate generator responsive to the ramp voltage and the sweep generator voltage and operating each time the value of the ramp voltage passes that of the sweep generator voltage to generate a gating signal which exists for a predetermined interval; a detector for converting a received reflected laser pulse into an electric signal; a pair of gating circuits controlled by the gating signal so that they define first and second successive gating intervals, each gate circuit being operative to pass said electric signal from said detector only if it arrives within the corresponding gating interval; means responsive to an excess of said electric signal passed in one of said gating intervals relative to the electric signal passed in the other of said gating intervals for modifying the output of the range sweep generator in a direction such that the timing of the gating intervals in relation to an elecTric signal from said detector occurring at the same time in the next ramp waveform results in a reduction in said signal excess; and a DC clamping circuit operative following each pair of gating intervals to restore the DC level of said range sweep generator.
Claim 2
Dependent Claim
242 words
A laser range finder comprising: a laser for emitting a succession of light pulses; a ramp generator producing a ramp voltage following the transmission of each laser pulse; a rangesweep generator producing a sweep signal having a progressive voltage variation extending over a number of ramp voltage cycles; a gate generator responsive to the ramp voltage and the sweep generator voltage and operating each time the value of the ramp voltage passes that of the sweep generator voltage to generate a gating signal which exists for a predetermined interval; a detector for converting a received reflected laser pulse into an electric signal; a pair of gating circuits controlled by the gating signal so that they define first and second successive gating intervals, each gate circuit being operative to pass said electric signal from said detector only if it arrives within the corresponding gating interval; means responsive to an excess of said electric signal passed in one of said gating intervals relative to the electric signal passed in the other of said gating intervals for modifying the output of the range sweep generator in a direction such that the timing of the gating intervals in relation to an elecTric signal from said detector occurring at the same time in the next ramp waveform results in a reduction in said signal excess; and a DC clamping circuit operative following each pair of gating intervals to restore the DC level of said range sweep generator.
Claim 3
Dependent Claim
89 words
A laser range finer in accordance with claim 1 further comprising sweep-control means for stopping the progressive voltage variation of the sweep signal from the range sweep generator, and said sweep control means further comprising a circuit responsive to the presence of an electric signal from said detector during said first or said second gating interval and having a time constant such that said progressive variation is stopped only when a number of said electric signals has been received from said detector following a number of successive laser pulses.
Claim 4
Dependent Claim
85 words
A laser range finder in accordance with claim 2 wherein said sweep control means further comprises: a third gate operating in timed relationship with said first and second gates so as to be in signal-passing condition for a period consisting of the total duration of said first and second gating intervals; and means responsive to the passage of a signal, corresponding to a reflected laser pulse, by said third gate for stopping the progressive voltage variation of said sweep signal from said range sweep generator.
Claim 5
Dependent Claim
94 words
A laser range finder in accordance with claim 1 wherein said range sweep generator comprises a pair of current sources of opposite polarities and an integrator for generating said sweep signal and a flyback signal, switching means connected between one of said current sources and said integrator, and a control circuit connected to receive a signal from said range sweep generator and operative to actuate said switching means when said sweep generator signal has a value between predetermined upper and lower limits, said limits corresponding to the ends of the required sweep signal variation.
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) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |