Low-Noise High-Accuracy TOF Laser Range Finder

This paper presents a new low-noise high-accuracy laser range finder based on the Time-Of-Flight (TOF) method. A Q-switched Nd:YAG laser at 1064 nm as a source and a SLIK avalanche photodiode as a detector are used. The optical section of the system including ZnS/MgF₂ optical filter, designed by C⁺⁺ and Zemax software, has been successfully implemented and tested. The quality factor of the optical filter is obtained about 2.53. Using the 1.5 MW Nd:YAG laser, the lowest detectable optical power is limited to about 8.14 nW. The absolute range finding error in the range of 0.3-20 km is also measured as δ_r= ± 50 cm. Furthermore, the sampling rate of the distance measurement can be adjusted between 1 and 20 samples per second.