Optimized Interference Suppression for TCSPC LiDAR

Abstract

The increased use of light detection and ranging (LiDAR) systems for distance determination requires the investigation of mutual interference. In this article, we describe the conditions for the occurrence of LiDAR interference. We outline suppression methods for different LiDAR types identifying pulse-position modulation (PPM) as a solution for time-of-flight LiDAR with time-correlated single photon counting (TCSPC) histograms. Based on PPM, we present a suppression method, which randomly varies the laser pulse emission times. For optimal suppression, we switch on the suppression only when interference is present. To recognize the occurrence of LiDAR interference, we develop a multipulse detection algorithm that can also extract all pulse positions. Simulations show that the algorithm can be applied for a signal-to-noise ratio greater than 3. Determining the heights of all recognized pulse signatures, an appropriate suppression level can be chosen. We successfully show the optimized interference suppression for an example LiDAR measurement. For safe use by multiple systems, we suggest random numbers. We reuse the TCSPC histograms to generate random numbers, whose generation probability is calculated theoretically and confirmed by simulation and measurement data. For nearly all histogram distributions consisting of background- and laser-generated data, a sufficient amount of random numbers is produced.