Design Of Lidar Velocity Measurement System Under Strong Infrared Radiation Background

Laser Doppler velocimetry system not only has the advantages of real-time,accuracy and quick response,but also can easily complete multi-dimensional velocity measurement in many fields.Therefore,in-depth study of this technology can not only promote the development of this technology,but also has a good market prospect.The paper begins with the introduction of the research project background and main purpose,the development history of laser velocimetry technology,research status and development trend at home and abroad,and then introduces the main research content of this paper.Then,the basic principle,method,signal form,signal processing method and several common optical path mode of doppler velocimeter are introduced in detail.Then,a high precision lidar speed measuring system is designed based on the project background.In order to solve the problem that the system is strongly interfered by infrared radiation when measuring the speed of high temperature target,a new scattering model and thermal radiation power calculation method are proposed to numerically simulate the signal power and thermal radiation noise power in the process of velocity measurement and then calculate the signal-to-noise ratio.The rationality of the model is verified by experiments,and the error is within 3%.According to this model,a range of velocity measurement distance is obtained.Through numerical simulation,the laser with appropriate wavelength can be quantitatively calculated to measure the speed,effectively improve the signal-tonoise ratio and reduce the loss of the instrument at high temperature,and it is fast and accurate.In addition,according to the signal-to-noise ratio formula,adjusting the device parameters makes the 1550 nanometer wavelength lidar velocity measurement system also feasible when it is used for high temperature target velocity measurement,which has important guiding significance for the design of velocity measurement system in high temperature environment.Then the FFT signal processing method is selected.Finally,according to our theoretical model,appropriate device parameters are selected to build a velocity measurement system to complete the speed measurement of high temperature solid targets.Accurately measured the speed,and do the error is less than 0.02m/s,has important guiding significance for industrial production.