Comparative Analysis of Radar and Lidar Technologies for Automotive Applications

Radars and lidars are two primary sensor modalities complementing optical cameras in active safety and autonomous driving applications. Radars and lidars operate at dramatically different frequency bands, experience different propagation effects, and are implemented using completely different technologies. Therefore, they also differ in operation, processing, and implementation challenges. Moreover, the lidar and radar communities have expertise in very disparate technologies and, therefore, are typically segregated and do not communicate. This work provides a fair comparison between lidars and radars, investigates similarities and differences between them, emphasizes their advantages, and summarizes their shortcomings. Lidar systems' advantages are their high angular resolution and spatiotemporal consistency. Radar systems' advantages are robustness to adverse weather and poor lighting conditions, long detection range, low cost, and the possibility for on-vehicle integration behind an optically nontransparent fascia. It is expected that 1) intensive research and development will enable future low-cost and long-range lidar technology, and 2) digital radars with a large number of transmit and receive channels will achieve lidar-like angular resolution and resolve mutual interferences while preserving other radar advantages.