Identification system using a laser retro-reflecting and modulating set
US4887310A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1987 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | Jul 24, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The system comprises a laser transmitter/receiver set which transmits laser radiation and processes the radiation received by retro-reflection and a remotely-placed retro-reflecting and modulating set which modulates the laser radiation and sends it back to the receiver. These two sets are mechanically separated, and one can be placed on board an aircraft and the other on the ground, for example. The modulation is done by a frequency-controlled acousto-optical deflector to obtained the operating conditions of diffraction according to Bragg's law. The laser radiation, after crossing the deflector, is sent back by a catadioptric device along its original path. The double passage through the deflector, on the way out and back, produces a shift in the frequency of the laser radiation, the value of the said shift being equal to twice the control frequency of the deflector. A double axis or single axis optical scanning device is added on, for functioning in a wide field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.