Research On Nonlinear VAD Method Of Continuous Coherent Wind LIDAR

The subject of this paper is from the Southwest Institute of Technical Physics’ project the Key Technologies of LIDAR (Light Detection and Ranging), which is to study continuous coherent wind LIDAR in the low-level small and middle scale atmospheric wind field, and to search the extraction method of the wind field information fast and accurately.Continuous coherent wind LIDAR has a lot advantages, such as low cost, small and compact shape, high precision, and widely used in low-altitude atmospheric wind field measurement, its specific detection method is:First, to emit a laser beam to the target airspace, thus to detect atmospheric the tiny particles (aerosols) in the wind drift of the laser backscatter by echo Doppler frequency shift, and then use the Doppler effect to calculate the radial velocity along the laser beam direction, coupled with the laser beam conical scanning non-contact dimensional measurement of a modern photovoltaic technology, and ultimately the atmospheric wind field.However, directing detection by LIDAR is merely the velocity along the beam direction (line of sight), and the needing information of the atmospheric wind field would need to be certain to inverse radial velocity, radial velocity inversion method has historically been one of the most important technical of the laser field measured wind radar in the atmospheric wind. There are many traditional radial velocity inversion method, during which the VAD (Velocity of Azimuth Display) method is the popular one, as its simple calculation, the computational load has been widely used, but due to VAD method is built on top of the uniform or linear wind field assumption, it is difficult to reflect the true atmospheric wind field, the true atmospheric wind field is often not uniform or linear, but non-linear wind field, so the nonlinear atmospheric wind field depth to have a stronger theoretical and practical significance.The purpose of this study is:the traditional VAD method based on the establishment of a linear wind field and the nonlinear wind farm has a good non-linear inversion effect of the VAD method, the method including nonlinear VAD inversion modeling technique and nonlinear VAD inversion algorithms.According to the research purpose of analysis, theoretical analysis and comparison, and with the comparison of the traditional VAD method and the nonlinear VAD method, we can draw the main research results of this paper:based on more complex than the traditional wind field, such as average or linear wind field nonlinear wind field, we establish a set of nonlinear VAD method, which is better than the traditional VAD method, the specific work is divided into two aspects:The first aspect is to improve the traditional VAD inversion techniques, then to build a linear wind field basing on nonlinear wind field by using the nonlinear VAD inversion of technology; the second aspect is the inversion of the coefficient of nonlinear wind field for the deficiencies of the traditional wind field retrieval algorithm improvements, proposed AGALM hybrid algorithm can quickly and accurately satisfied anti-performance needs of the information of three-dimensional wind field.