Improved indirect time of flight (i-ToF) measurements for LiDAR with and without gain on the avalanche photodetector (APD)

Abstract

Switching modulation involving two or more frequencies exhibits outstanding performance for indirect time-of-flight (i-ToF) LiDAR to address a problem with resolution and ambiguity range. However, the accuracy and precision remain issues when a target is far from the system due to a poorly received signal. This work improves a LiDAR system by introducing adjustable gain on the avalanche photodetector (APD) to enhance the accuracy and precision. The system was experimentally characterized by measuring a target at 5, 25, and 45 meters with gain settings of maximum, middle, and no gain. The middle and maximum gain settings improved the signal-to-noise ratio (SNR), accuracy, and precision. Furthermore, the proposed system may be appropriate for environmental remote-sensing systems, such as mapping and autonomous navigation.