Chirp and Doppler optical gauge
US4861158A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1987 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Sep 30, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/87
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A laser distance gauge measures the distance and shape of a target by alternately performing (a) a Doppler shift measurement during optical scanning of the target's surface and/or motion of the target and (b) a chirp measurement with a chirp frequency laser signal. To ascertain changes in radial distance from the gauge to the target, the Doppler shift information is integrated and the result is combined with absolute distance measurements made in the chirp mode. A single CW laser, which operates single frequency, serves for both types of measurement. A computer changes the gauge from Doppler mode to chirp mode when the Doppler shift reaches a predetermined amount. When a chirp measurement of absolute distance is completed it reverts to Doppler mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.