Photon budget of long range FMCW LiDAR: a comprehensive spectral-temporal model with experimental validation

A comprehensive model for the photon budget of FMCW LiDAR has been developed for automotive applications and validated through a series of long-range experiments. Based on this model, analytical SNR expressions are derived, covering the typical limit cases of the operating regimes. The maximum detection distance of FMCW LiDAR is further evaluated using this model, establishing a quantitative relationship with key design parameters, including laser power, signal linewidth, measurement time, and the number of FFT points. Based on these results, system design trade-offs concerning the number of channels, laser power consumption, and data rate/resolution are also discussed, providing additional design considerations and performance expectations for future automotive-grade FMCW LiDARs.