Research on Frequency Modulated Continuous Wave (FMCW) Lidar Equation Based on Optical Mixing

Frequency Modulated Continuous Wave (FMCW) lidar exhibits excellent anti-interference capabilities and efficient range and velocity measurement performance. Operating range is a crucial metric for FMCW lidar systems. To address the limitations of traditional radar equations, which do not account for optical mixing and balanced detection, a FMCW lidar equation based on optical mixing has been derived. This equation incorporates parameters such as the FMCW lidar system, average noise power, signal-to-noise ratio, and coherent detection gain, while also considering the relationship between atmospheric transmittance and operating range. Finally, an experimental FMCW lidar system with a wavelength of 1550 nm was constructed to test the operating range for water surface tar-gets. The experimentally measured average maximum range was 272.49 m, while the maximum operating range calculated using the derived lidar equation was 293.60 m, with a relative error of 7.74%, thereby validating the accuracy of the equation. This equation can be applied to evaluate the maximum operating range of FMCW lidar in various environments, such as autonomous driving and low-altitude surveillance, providing theoretical support for the design and performance assessment of FMCW lidar systems.