Dual-Pulse Anti-Interference and Time Discrimination for Automotive ToF LiDAR

LiDAR that provides accurate and dense 3D information regardless of lighting conditions possesses a significant position in autonomous vehicles, and is considered as an indispensable sensor for the safety of high-level autonomous driving. However, with increasing vehicles mounted LiDARs on road, safety issue brought by interference among sensors becomes prominent. Anti-interference based on coding and modulation requires complicated system structures and algorithms. Therefore, we propose a dual-pulse time discrimination method to simultaneously range and eliminate interference from offending LiDARs. The method has a simple circuit topology, combining anti-interference into time discriminator to reduce the complexity of the sensor system. It also removes the complex delay devices which is required in a conventional CFD. The inherent time delay in dual pulses gives clue to authenticate ranging pulses from interference. More importantly, detailed analysis on interaction between ranging pulses and interference pulses is revealed. Experimental results show that the proposed dual-pulse time discriminator achieves excellent anti-interference and ranging performance. Our proposed method achieves a reduction in false ranging of over 98%, with a complete (100%) reduction at shorter distance, with a threshold of >10 standard deviations from the mean. The robust performance of the proposed dual-pulse CFD would be of great significance in improving the safety of autonomous driving.