Simulation of a Direct Time-of-Flight LiDAR-System

The simulation of a direct time-of-flight flash light detection and ranging (LiDAR) system is crucial for the assessment of the system performance during sensor development. However, due to the number of components of the LiDAR system and the optical signal path and their parameter uncertainty, simulation models are often difficult to validate. In this article, a simulation model is proposed, which extends the statistical simulation of the direct time-of-flight method and incorporates different sensor characteristics. Based on a Poisson process with a subsequent Monte Carlo simulation, various detector types are implemented to examine the detection behavior during prototype construction. The detector types considered here include the single-photon avalanche diode (SPAD), the SPAD array, the silicon photomultipliers (SiPM), and the SiPM array. These are simulated in interaction with a LiDAR system, which in addition to the sensor consists of the emitter, signal path, object, and receiver optics modules. Each of them is defined by several individual system parameters. After derivating the photon detection rate, the implementation of the detector-specific parameters, such as dead time, afterpulsing, crosstalk, and threshold, are considered in more detail. Nonideal tunings during prototyping, which are accompanied by the consideration of the pulse shape, the illuminated/observed object area, as well as the actually used detector area, are also considered.