Distance measuring system

摘要

A modulated light beam from a radiation source on a structure whose position is to be measured is split into a first beam which propagates through the atmosphere to a first detector and a second beam which travels through an optical fiber to a second detector. The first and second detectors recover the modulation on the first and second beams, the phases of which are compared to determine the distance. In a preferred embodiment, the light source is a sine-wave modulated laser.