Development of a time-of-flight lidar photodetector module
V.V. Cherepanov1,2, S.P. Bukin1,2, A.B. Kleschenkov1,2,
S.V. Krutiev1,2, S.D. Moshichenko1,2, N.V. Gorbachev1;
1Southern Federal University, Rostov-on-Don, Russia
2LLC "NPO SMARTSENS", Rostov-on-Don, Russia
Abstract
Scanning laser rangefinders (lidars) based on time-of-flight measurement are high-tech devices and combine a number of complex components of digital, analog electronics, as well as elements of an ultra-precise mechanical and optical scanning system. A complete analysis of the effectiveness of the entire receiving and transmitting system, including a laser emitter, an optical system and a photodetector (PD), is required. PIN and avalanche semiconductor photodiodes (APD) with their own photocurrent multiplication coefficient are widely used in the development of the lidar receiving part as a photosensitive element. In this work, a PD model has been developed in the LTspice software according to the classical scheme using APD, broadband transimpedance and operational amplifiers. The results of the calculation of the main time diagrams of voltages and currents of the PD for various APD bias voltages are presented. Based on the data obtained, the limiting operating modes are determined when the PD switches to voltage saturation mode (in which the distance determination error increases significantly due to the ambiguity of fixing the flight time at a fixed echo signal level), or does not capture a low-amplitude echo signal. To assess the dynamic range of distance measurement, the PD model is supplemented with the possibility of taking into account the power of the emitted pulse of the laser diode, the efficiency of the optical system of the emitter and receiver, the radii of the lenses, as well as the reflection coefficient of the surface. Thus, the problem of evaluating the effectiveness of the entire receiving and transmitting system (emitter, optics and PD) has been solved. A model of a controlled pulse step-up voltage converter (VC) has been developed to generate an offset voltage. Models of the PD, VC were made and experimental measurements of time diagrams of currents and voltages for various distances to objects and reflective abilities were carried out. The results of computer simulation and experiment are compared.
Speaker
Sergey Bukin
Southern Federal University
Russia
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