Doppler Wind Lidar Adopting Radio-Frequency Edge Discriminator

Objective Coherent Doppler wind lidar (CDWL) requires real-time signal processing with high computational complexity, which hinders the development of portable systems with high spatiotemporal resolution and long detection ranges. Despite successful implementations in various fields, high sampling rate analog- to- digital converters (ADCs) and real-time signal processing with digital signal processing (DSP) or graphics cards pose challenges for subsequent data storage and processing.<br /> Methods We propose a Doppler shift estimation method using a real-time radio frequency (RF) discriminator in CDWL. Inspired by the direct detection Doppler wind lidar (DDWL), this method converts the returned laser signal into easily processed electrical signals through a balanced detector. Subsequently, a low- complexity frequency extraction is achieved using an RF edge discriminator.<br /> Results and Discussions In the demonstration experiment, the comparison results between the proposed CDWL and the conventional CDWL show good consistency under both weak and strong wind conditions. Specifically, under strong wind conditions, a radial wind velocity difference of less than +/- 1 m/s is achieved within a range of 2 km, with a spatiotemporal resolution of 30 m and 0.1 s.<br /> Conclusions By combining the advantages of CDWL and the edge technology DDWL, we propose and demonstrate a real-time data processing CDWL based on an RF edge discriminator. The results of the comparative experiments verify the feasibility and effectiveness of the new method.