A Sliding Window DFT Method for Coherent LiDAR Spectrum Analysis

Abstract

The invention belongs to the technical field of coherent laser wind measuring radar, and discloses a sliding window DFT used for coherent laser wind measuring radar spectrum analysis method, based on the contradiction that the distance resolution and frequency resolution of the pulse system coherent laser wind measuring radar cannot be improved simultaneously , using the sliding window DFT method; increasing the number of Fourier analysis points to improve the spectral resolution by introducing the sampling data of the front and rear distance libraries, and using the sampling points smaller than the pulse width in time as the sliding points to improve the distance resolution. The sliding window DFT of the present invention can effectively improve the spectral resolution and the distance resolution; the effect of improving the spectral resolution is proportional to the number of points before and after the introduction, and the effect of improving the distance resolution is inversely proportional to the number of sliding points of a single SDFT; compared with the existing segmented DFT Compared with the method, the spectral peak shape of the radar signal is more prominent, the accuracy of the spectral peak position is higher, and the wind speed measurement is more accurate; for the case of large wind speed shear, the windowed sliding window DFT is used to effectively control the wind measurement accuracy.

Description

technical field [0001] The invention belongs to the technical field of coherent laser wind-measuring radar, and in particular relates to a spectral analysis method for coherent laser wind-measuring radar using sliding window DFT. Background technique [0002] Coherent laser wind radar targets aerosols and air molecules to detect their backscattering information. It is a detection device that can truly and effectively invert the three-dimensional wind field of the atmosphere. It has a wide range of applications in the fields of meteorological monitoring, energy development, and aviation security. Application prospect. Especially for aviation support, the accurate observation of wind speed is very important for the identification of wind shear. Compared with the conventional electromagnetic band weather radar, the operating wavelength of lidar is short, and the frequency shift generated by unit radial Doppler velocity is relatively large. Its spectrum analysis is usually comp...

AI Technical Summary

Problems solved by technology

[0005] To sum up, the existing problems in the existing technology are: signal zero padding method, which produces a large side lobe, which changes the spectral width of the radar signal; spline function interpolation technology, too few interpolation samples, poor real-time performance, and reliable accuracy Significant impact on noise ratio; existing pulse compression techniques cannot be applied to coherent LiDAR

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