Research On Cn2 Based On Temperature Pulsator In Changchun Area

With the development of space laser communication,the measurement of atmospheric optical parameters is becoming more and more important.The optical turbulence in atmospheric channels is an important factor that restricts the development of space laser communication.The random fluctuation of refractive index caused by atmospheric turbulence can affect the quality of space laser communication.Studying and measuring the structural constant of atmospheric refractive index（C_n²）is an important way to explore atmospheric optical turbulence.This article will explore the principles of atmospheric optics.Based on Kolmogorov’s theory of locally uniform isotropic turbulence,a Temperature pulsator equipment will be developed using the idea of measuring the refractive index structure constant of the atmosphere using two-point temperature fluctuations.A sensor probe made of platinum wire is used to detect temperature fluctuations in atmospheric space,invert the atmospheric refractive index structure constant,and draw a characteristic curve of the atmospheric refractive index structure constant.A set of atmospheric refractive index structure constant measurement platform has been built.The developed Temperature pulsator equipment has optimized its structural design and added Kalman filtering algorithm,enhancing the durability,convenience,and accuracy of the equipment.The entire equipment has small size,light weight,low power,high accuracy,rain and dust resistance.The independent power supply can achieve long-term measurement of atmospheric refractive index structure constant outdoors,meeting more experimental needs and promoting the popularization of atmospheric turbulence testing equipment.A performance analysis system suitable for Temperature pulsator equipment has been established based on the design of performance indicators of Temperature pulsator instruments based on atmospheric turbulence environment.After experimental analysis,the temperature pulsation instrument achieves a measurement range of atmospheric refractive index structure constant in terms of performance:10^-18m^-2/3～10^-12m^-2/3,uncertainty of11.08%,noise as low as 0.001K,measurement sensitivity of 1.44V/℃,and good measurement consistency of the equipment.To provide technical reference for more convenient and accurate measurement of atmospheric refractive index structure constant.Three observation points were built based on a Temperature pulsator to measure the atmospheric refractive index structure constant in Changchun area,and the daily variation characteristic curve of the atmospheric refractive index structure constant was drawn to analyze the characteristics of the atmospheric refractive index structure constant in Changchun area.The atmospheric refractive index structure constant at the three observation points presents the same daily variation law,and the probability density is generally normal distribution.Using multiple observation points to simultaneously measure and study the spatial correlation of atmospheric refractive index structure constants,the order of magnitude and trend of variation of atmospheric refractive index structure constants are generally consistent within a 10km spatial range,with numerical differences.The Pearson correlation coefficient is 0.402,indicating a significant correlation between atmospheric refractive index structure constants in space.Provide data reference for atmospheric parameter measurement.