ABSTRACT
Telemeters or rangefinders are implemented by three technologies: triangulation, time-of-flight and interferometry, described in details in this chapter. To start, the range equation relating received and transmitted powers is derived for co-operative (i.e., corner-cube) and non-cooperative targets, along with the system equation relating range to power and noise. The equation of precision for a threshold-crossing timing of received pulse is then derived and illustrated with examples. The same analysis is repeated for a sine-wave modulated telemeter. To optimize precision, the optimum filtering is presented. Technology issues like single or double optics, ambiguity range, and decimal readout, are then considered and solutions outlined. The long-pulse operation of LiDAR rangefinder is analyzed in details, as well as the operation of a pulsed LIDAR to monitor pollution and physical parameters of the atmosphere.
