How do you achieve precise time synchronization across multiple sensors in an autonomous vehicle?

Time synchronization approach: 1) Hardware synchronization - PTP (Precision Time Protocol, IEEE 1588) for network time, GPS-based timing (PPS signal), hardware trigger lines for cameras and lidar; 2) Software alignment - timestamp interpolation, motion compensation for time offsets, buffer management for different sensor rates; 3) Calibration - measuring and compensating for systematic delays (sensor processing, network latency); 4) Architecture - central timing master, synchronized capture across sensors, common reference clock; 5) Validation - measuring synchronization accuracy, monitoring drift. Target accuracy depends on application (microseconds for lidar-camera, milliseconds for radar). Poor synchronization causes fusion errors: Objects appear at wrong positions, velocity estimation errors, and misalignment between sensor modalities.