Phase-Coded FMCW Lidar

Light detection and ranging (lidar) is considered to play an important role for future advanced driver assistance systems and autonomous driving. Coherent lidar systems, which have several benefits over conventional direct detection systems, are commonly modulated by frequency modulated continuous wave (FMCW). However, FMCW lidar systems can face severe ambiguities due to high Doppler shifts or in multi-target scenarios. Hence, this paper presents a novel modulation approach for coherent lidar that combines conventional FMCW with a pseudorandom binary phase code in order to overcome possible ambiguities while maintaining a lean system setup. The proposed approach is evaluated by simulations and measurements revealing similar single-target performance as a FMCW reference system with an ideal quadrature demodulator.