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Patent US4613231A successfully refreshed from Google Patents.
US4613231A
Expired / Lapsed
US
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Laser range finder with non-linearity compensation
Assignee: Eltro GmbH and Co
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Filing: 1984-03-07
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Granted: 1986-09-23
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Expires: 2004-03-07
Abstract
Abstract The receiver (3') of a laser range finder operating on the pulse propagation and including a transmitter unit (1) and a first receiver unit (2) is sampled by a spike pulse (5) derived from the transmitter pulse in such a way as to produce a low-frequency representation (10). The non-linearity of the phase modulation of this spike pulse, which is detrimental in very accurate measurements taken over long distances, is eliminated in that the oscillations of high-frequency oscillator (8) are supplied to a second receiver unit (2') in which they are scanned by the same spike pulse (5) and are then also suitably transformed into a low-frequency representation (10'). A counter (12) then counts the low-frequency zero-passages of the oscillator, beginning with the onset of the low-frequency cycle, thereby eliminating all errors (FIG. 1).
Inventors
- 👤 Guenter Wichmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:06
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; F; F42; F42C; F42C13/00; F42C13/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
212 words
A laser range finder, comprising: (a) transmitter means for providing transmitter pulses; (b) light emitting means for emitting light pulses in response to said transmitter; (c) modulation generation means for generating a phase modulation control signal; (d) phase modulation means responsive to said transmitter means and said modulation generation means to produce pulses delayed in time with respect to said transmitter pulses by a delay proportional to said phase modulation control signal; (e) first receiver means for receiving reflections of said transmitted light pulses reflected by an object whose range is to be measured; (f) sampling means responsive to said first receiver means for generating a first low-frequency representation of the reflected pulses; (g) trigger means responsive to said sampling means to produce a trigger signal in response to the first low-frequency representation produced by said sampling means; (h) high-frequency oscillator means for generating high-frequency oscillations with a frequency which corresponds to the desired accuracy of measurement; (i) means for transposing said high-frequency oscillations, utilizing a sampling pulse, into a second low-frequency representation; and (j) counter means for counting the low-frequency zero-crossings of the second low-frequency representation produced by said means for transposing said high-frequency oscillations, said counts beginning with the onset of the low-frequency cycle produced by said modulation generation means.
Claim 2
Dependent Claim
212 words
A laser range finder, comprising: (a) transmitter means for providing transmitter pulses; (b) light emitting means for emitting light pulses in response to said transmitter; (c) modulation generation means for generating a phase modulation control signal; (d) phase modulation means responsive to said transmitter means and said modulation generation means to produce pulses delayed in time with respect to said transmitter pulses by a delay proportional to said phase modulation control signal; (e) first receiver means for receiving reflections of said transmitted light pulses reflected by an object whose range is to be measured; (f) sampling means responsive to said first receiver means for generating a first low-frequency representation of the reflected pulses; (g) trigger means responsive to said sampling means to produce a trigger signal in response to the first low-frequency representation produced by said sampling means; (h) high-frequency oscillator means for generating high-frequency oscillations with a frequency which corresponds to the desired accuracy of measurement; (i) means for transposing said high-frequency oscillations, utilizing a sampling pulse, into a second low-frequency representation; and (j) counter means for counting the low-frequency zero-crossings of the second low-frequency representation produced by said means for transposing said high-frequency oscillations, said counts beginning with the onset of the low-frequency cycle produced by said modulation generation means.
Claim 3
Dependent Claim
67 words
A laser range finder as in claim 1, wherein said means for transposing said high-frequency oscillations is a second receiver means responsive to said high-frequency oscillator means, said second receiver means using a sampling pulse to produce a low-frequency representation which is applied via a low-frequency amplifier to said counter means, and wherein said counter means is stopped by the low-frequency signal from said first receiver means.
Claim 4
Dependent Claim
19 words
A laser range finder according to claim 2, wherein the high-frequency oscillator means is a constant-frequency crystal controlled oscillator.
Claim 5
Dependent Claim
206 words
A laser range finder, comprising: (a) transmitter means for providing transmitter pulses; (b) light emitting means for emitting light pulses in response to said transmitter means; (c) modulation generation means for generating a phase modulation control signal which scans a range of values; (d) phase modulation means responsive to said transmitter means and said modulation generation means to produce pulses delayed in time with respect to said transmitter pulses by a delay proportional to said phase modulation control signal; (e) first receiver means for receiving reflections of said transmitted light pulses reflected by an object whose range is to be measured; (f) first sampling means responsive to said first receiver means and said phase modulation means for generating a first low-frequency representation of the reflected pulses; (g) trigger means responsive to said sampling means to produce a trigger signal in response to the first low-frequency representation produced by said sampling means; (h) high-frequency oscillator means for generating high-frequency oscillations; (i) second sampling means responsive to said phase modulation means for transposing said high-frequency oscillations, utilizing a sampling pulse, into a second low-frequency representation; and (j) counter means for counting the low-frequency zero-crossings of the second low-frequency representation produced by said means for transposing said high-frequency oscillations.
Claim 6
Dependent Claim
206 words
A laser range finder, comprising: (a) transmitter means for providing transmitter pulses; (b) light emitting means for emitting light pulses in response to said transmitter means; (c) modulation generation means for generating a phase modulation control signal which scans a range of values; (d) phase modulation means responsive to said transmitter means and said modulation generation means to produce pulses delayed in time with respect to said transmitter pulses by a delay proportional to said phase modulation control signal; (e) first receiver means for receiving reflections of said transmitted light pulses reflected by an object whose range is to be measured; (f) first sampling means responsive to said first receiver means and said phase modulation means for generating a first low-frequency representation of the reflected pulses; (g) trigger means responsive to said sampling means to produce a trigger signal in response to the first low-frequency representation produced by said sampling means; (h) high-frequency oscillator means for generating high-frequency oscillations; (i) second sampling means responsive to said phase modulation means for transposing said high-frequency oscillations, utilizing a sampling pulse, into a second low-frequency representation; and (j) counter means for counting the low-frequency zero-crossings of the second low-frequency representation produced by said means for transposing said high-frequency oscillations.
Claim 7
Dependent Claim
33 words
Apparatus as in claim 4, wherein said count begins with the onset of a scan in the low-frequency cycle produced by said modulation generation means and ends in response to said trigger signal.
References Cited (Backward Citations)
US3900260A
Cited
USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1989-09-22 | 1990-03-24 | 1990-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-22 | 1994-03-24 | 1994-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-22 | 1998-03-24 | 1998-09-23 | $7700.00 | Window Closed / Lapsed |