Electro-optic distance measuring device
US4171907A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 1978 |
| Grant date | Oct 23, 1979 |
| Priority date | — |
| Expiry date | May 25, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device for measuring distances to a target includes electronic circuits for generating a light which is amplitude modulated by three selectable frequencies. Also included are optics for focusing the amplitude modulated light onto the target, and for receiving reflection of the light therefrom. Additional circuits convert the received light to electrical signals representative thereof, and compute the phase angles between these signals and the amplitude modulating signals. The distance to the target is then calculated based on these phase angles and the wavelength of frequencies equal to the differences between the three selectable frequencies. Another circuit uses an accelerometer to measure vertical angle to the target, and further distance measurements are made based thereon. Still other circuits compensate for a variety of potential error causing conditions, such as signal waveform asymmetry and component tolerance. A subassembly of the device is mountable on a theodolite telescope and utilizes folded optics in order to be plungeable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.