Spatial resolution enhancement of coherent Doppler wind lidar using differential correlation pair technique

Abstract

A high spatial resolution coherent Doppler wind lidar (CDWL) incorporating the differential correlation pair (DCP) technique is proposed and demonstrated. By employing pulse pair with appropriate window functions, the spatial resolution can be enhanced, as the common parts of the correlation pair can be eliminated in the differential data processing. The performance of the new method is validated in the comparison experiment with the CDWLs adopting conventional schemes. Under a given peak power, the DCP technique provides higher wind velocity accuracy compared with a conventional pulsed CDWL where the laser spectral broadening caused by short pulses can be avoided and the carrier-to-noise ratio is improved. At a laser peak power of 250 W, with a spatial and temporal resolution of 3.3 m and 1 s, continuous radial wind profiling over 700 m is realized with a maximum error of 0.1 m/s.

Doppler Wind Lidar From UV to NIR: A Review With Case Study Examples

“…Another attempt to improve the distance resolution is the DCP technique (Zhang et al, 2021). By employing pulse pair with appropriate window functions, the DCP scheme offers an approach to improve the distance resolution without broadening the spectrum width.…”

“…Since the spatial resolution enhancement of DWL is generally achieved by reducing the pulse duration of the transmitted laser according to the basic lidar equation, it inevitably induces the sacrifice of other properties, such as the SNR, maximum detection range, and realtime data processing of C-DWL. To solve this problem, various methods have recently been developed in the C-DWL, including a joint time-frequency analysis (JTFA) method (Wang et al, 2018), Golay coding technique (Wang et al, 2019), and differential correlation pair (DCP) technique (Zhang et al, 2021). Apart from the derived LOS wind speeds, C-DWL also provides a spectrum information that has been applied for precipitation observation (Wei et al, 2019), cloud identification (Yuan et al, 2020), and other applications (Wei et al, 2021).…”

Turbulence Detection in the Atmospheric Boundary Layer Using Coherent Doppler Wind Lidar and Microwave Radiometer

“…Coherent Doppler wind lidar (CDWL) obtains radial wind speed information by retrieving the frequency shift of the received signal after passing through a distance in the atmosphere [40][41][42]. Its reliable performance has been verified in various areas, such as the following: turbulence parameters [43][44][45][46][47], aircraft wake vortices [48], boundary layer height [49][50][51], cloud seeding [52], gravity waves [53,54], low-level jets (LLJs) [44,55,56], simultaneous wind and rainfall detection [57], identifying different atmospheric environments [58], and others [59,60].…”

High Resolution Coherent Doppler Wind Lidar Incorporating Phase-Shift Keying

“…However, to achieve the fast phase transition between bits, a very high modulation bandwidth is required. Another attempt is the differential correlation pair (DCP) method [24], where the spatial resolution is determined by the duration of the short probing pulse and the window function. Under this scheme, the spatial resolution is enhanced to 3.3 m. However, due to the different intensity envelopes of the paired pulses, the pulse shape before amplification needs to be particularly designed to adapt to the gain characteristics of the amplifier, so as to ensure the cancellation of the common pulses.…”