Time of flight based lidar

In this study, how a time of flight (TOF) based light detection and ranging (LiDAR) works and how LiDAR systems can be done is investigated. The focussed part of the LiDAR is the receiver circuit. Photodiodes produce a very low current in response to light. This low photodetector current should be amplified in a fast and noiseless way. For this reason, a trans-impedance amplifier (TIA) circuit is designed and simulation results are shown. A comparator circuit should compare the output voltage of the trans-impedance amplifier and produce a stop signal for field programmable gate array time to digital converter FPGA TDC. Therefore, a fast comparator circuit with low overdrive dispersion is designed and simulation results are shown. To measure the distance by calculating the time of flight of the light, an FPGA TDC is designed and test experiments are done. A simple and cheap analog timer circuit is designed, and simulation results are shown in addition to FPGA TDC. LiDAR systems must measure time in a very accurate way. The calculation of signal processing times of electronic components in LiDAR systems is vital. It is found and shown in the simulation results that TIA signal processing time changes according to photodetector current magnitude and comparator signal processing time changes with the output voltage of TIA. Two objects with different reflectances at the same distance can be perceived as different positions by LiDAR systems and it is shown by simulation results. In summary, how to perform a precise time measurement for LiDAR systems is researched and supported by simulation results.