Optical velocimeter
US5000566A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 1990 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Jan 5, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P13/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This optical velocimeter may be installed in an aircraft to measure the true airspeed and the angles of attack and of sideslip of the aircraft. Alternatively, the velocimeter may be mounted in a wind tunnel to measure the velocity of the airstream passing through the wind tunnel. In either case, the points of reference for measurement are the large number of aerosol particles that are entrained in the air and are assumed to have the same velocity as the oxygen and nitrogen molecules of the air itself. The velocimeter comprises a plurality of optical transmitters and optical receivers. Each transmitter includes a laser operated in the continuous-wave mode and a laser operated in the pulsed mode. The laser operated in the continuous-wave mode generates a "precursor light sheet" at some distance from the aircraft whose velocity is to be measured or in the wind-tunnel airstream whose velocity is to be measured. When an aerosol particle intercepts the precursor light sheet, the laser operating in the pulsed mode, after a suitable time delay, generates a "first successor light sheet," which is in turn intercepted by the aerosol particle. The time of such interception is registered and in…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.