Device for calibrating distance-measuring apparatus
US6463393B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1999 |
| Grant date | Oct 8, 2002 |
| Priority date | — |
| Expiry date | Apr 21, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S7/497
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transmitter emits high-frequency modulated optical radiation which is reflected by an object and is received by a measurement receiver. Part of the transmitter radiation is decoupled as reference radiation and guided via a calibration path to a reference receiver whose electrical signals are fed to a frequency mixer. The frequency mixer and avalanche photodiodes acting as measurement receivers of the measuring radiation are interconnected directly via an electrical connection line upon which a mixer frequency acts. As a result thereof, optoelectronic calibration which completely compensates for the temperature-dependent phase shifts of the avalanche photodiodes is possible. Additionally, the phase shifts generated in the reference and receiver signals by the temperature drifts of the transmitter compensate one another. The overall accuracy of the distance measurement can be increased, particularly for short measuring times and immediately after the apparatus has been switched on. Furthermore, in comparison with a successive mechanical calibration process, the measuring times are halved and advantages in terms of weight, cost, and reliability are afforded since a mechanical change…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.