Distance measurement by laser light
US4744653A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 1985 |
| Grant date | May 17, 1988 |
| Priority date | — |
| Expiry date | Apr 10, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and apparatus for measuring a distance to an object includes directing first and second laser beams having frequencies .omega..sub.11 and .omega..sub.12 toward the object. A first reference signal is derived having a beat frequency .omega..sub.1 =.omega..sub.11 -.omega..sub.12. A first reflected light beam reflected from the object is detected and has the beat frequency .omega..sub.1 and a first phase difference with respect to the first reference signal. The first phase difference is then extracted from the first reference signal and the first reflected light beam and a first plurality of distance nodes is calculated from the first phase difference. Then, the frequency of the second laser beam is changed to .omega..sub.13. A second reference signal having a beat frequency of .omega..sub.2 =.omega..sub.11 -.omega..sub.13 is then derived. A second reflected light beam reflected from the target is detected and has the beat frequency of .omega..sub.2 and a second phase different with respect to the second reference signal. The second phase difference is then extracted from the second reference signal and the second reflected light beam and a second plurality of distance nodes i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.