Reduction of Distance Drift with Temperature in Uniaxial Laser Rangefinder by Using Multiecho Sensing

Uniaxial laser rangefinderTo expand the range of activities by unmanned aerial vehicles (UAVs), whose use at disaster sites and other dangerous locations has raised high expectations, UAVs must be capable of several functions, e.g., flight both indoor and outdoor environments. This requires making the airframe and major sensors as compact and light-weight as possible. To do so, we are developing uniaxial laser rangefinders to replace conventional scanning laser rangefinders. One developmental approach to uniaxial laser rangefinders and results regarding their validity are reported in this paper. Using a simulated model -- a modified scanning laser rangefinder -- we discuss the effectiveness of our approach. Specifically, this is to reduce the range drift due to heat, for which we propose using a multiecho to measure two echoes from a reference plate whose distance is known and that is placed outside of the sensor, and the target object, instead using the internal reference plate used in conventional two-dimensional scanning laser rangefinders. We also report the results of experiments verifying its validity.