High Resolution with Low Code Rate Random Modulation Cw Lidar for Range Imaging

Abstract

Light detection and ranging (LiDAR) is very important to improve the reliability of autopilot. A laser ranging method for 3D MEMS LiDAR is proposed in this paper. Firstly, The laser diode is intensity modulated with the mixed code of M-sequence and data code. Its enhanced resolution is achieved via matched filter and delay locked loop (DLL) technique, lowering the requirement of code rate and the analog-to-digital converter sampling rate. Its mathematical model is presented, including its nalytical solution. Analytical and experimental results demonstrate its capability to achieve distance precision of less than 2 cm within 8 ns (125 MHz) acquisition time, while the processing gain is about 48 dB. In addition, this enhanced capability remains constant over long distance without periodic ambiguities, make it ideal for range imaging.

Keywords: 3D LiDAR, laser ranging, RMCW, DLL, range imaging