Patent US3848999A successfully refreshed from Google Patents.
US3677646A
Expired / Lapsed
US
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Instrument for measuring distance
Assignee: Linde Sverige AB
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Filing: 1969-09-08
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Granted: 1972-07-18
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Expires: 1989-09-08
Abstract
Abstract A distance measuring instrument of the type wherein a modulated beam of light is transmitted along a path to be measured, the light is reflected at the distance to be measured and received at the instrument, and a comparison is made between the modulation phase of the received signal and that of the transmitted signal to determine the distance in terms of the wavelength of the modulation signal, includes an arrangement for varying the wavelength in inverse proportion to the sine or cosine of the angle of elevation whereby the measurement obtained is related to the vertical or horizontal projection of the distance irrespective of the elevation of the instrument.
Inventors
- 👤 Carl Erik Granqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:48
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/32
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
166 words
An instrument for determining the projected distance to a target object from a point at an altitude different from that of the target object, comprising an optical unit for transmitting a beam of light and receiving a beam of light along the optical axis thereof, means for varying the elevation of said optical unit, a light transmitter for supplying a beam of light to be transmitted by said optical unit, a light receiver for receiving the light received by said optical unit, a modulation signal source connected to said transmitter for producing a modulation signal for modulating the transmitted beaM of light and having a control input for varying the wavelength of said modulation signal, means for measuring the modulation phase difference between the transmitted and received light, means responsive to the elevation of said optical unit for generating a control signal in accordance with the elevation of said unit, and means for applying said control signal to the control input of said modulation signal source.
Claim 2
Dependent Claim
166 words
An instrument for determining the projected distance to a target object from a point at an altitude different from that of the target object, comprising an optical unit for transmitting a beam of light and receiving a beam of light along the optical axis thereof, means for varying the elevation of said optical unit, a light transmitter for supplying a beam of light to be transmitted by said optical unit, a light receiver for receiving the light received by said optical unit, a modulation signal source connected to said transmitter for producing a modulation signal for modulating the transmitted beaM of light and having a control input for varying the wavelength of said modulation signal, means for measuring the modulation phase difference between the transmitted and received light, means responsive to the elevation of said optical unit for generating a control signal in accordance with the elevation of said unit, and means for applying said control signal to the control input of said modulation signal source.
Claim 3
Dependent Claim
59 words
An instrument as claimed in claim 1, wherein said elevation responsive means comprises means for adjusting the value of the control signal for first and second predetermined values of the elevation, said instrument further comprising a pair of levels mounted thereon, each of said levels assuming a horizontal position at a corresponding one of said predetermined values of elevation.
Claim 4
Dependent Claim
49 words
An instrument as claimed in claim 2, wherein said modulation signal source comprises a master oscillator, a frequency-controlled oscillator and means for deriving reference frequencies from the master oscillator corresponding to said predetermined values of elevation and for comparing said derived frequencies with the frequency of said frequency-controlled oscillator.
Claim 5
Dependent Claim
51 words
An instrument as claimed in claim 3, wherein said frequency comparing means comprises a first mixer having a first input for receiving the reference frequency and a second input for receiving a frequency derived from the frequency-controlled oscillator, and a frequency measuring device selectively connectable to the output of said mixer.
Claim 6
Dependent Claim
57 words
An instrument as claimed in claim 4 further comprising a second mixer having a first input connected to the output of said first mixer and an output selectively connectable to said frequency measuring device, and a counter having an input connected to said master oscillator and an output connected to a second input of said second mixer.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |