Research On Refraction Error Correction Method Based On Mapping Function Method

With the development of science and technology,modern war requires in-service radar to achieve reliable and fast positioning function.However,radio waves are affected by the earth's atmosphere in the process of propagation,and atmospheric refraction error has become one of the important factors affecting the accuracy of radar and other radio systems.Due to the complexity of changes in the earth's atmosphere,it is of great significance to make a research on the correction method of atmospheric refraction error and adjust the parameters of atmospheric refraction error correction model according to the actual conditions.Based on the mapping function method,this paper focuses on the inversion optimization and correction method of atmospheric refraction error,and analyzes the accuracy and application of the inversion method.The following is our work.Firstly,the basic theory of atmospheric refraction—the description of radio transmission environment and atmospheric refraction error correction method are discussed.Based on the meteorological observation data of China,the application of Hopfield atmospheric profile model and sectional atmospheric profile model in China is analyzed.Based on the meteorological data provided by IGS tropospheric products,the correction effect of different mapping function models and the application of zenith delay model in China are analyzed.According to the results of analysis: the model coefficients of fixed atmospheric refraction error correction method can't correct the atmospheric refraction error well due to the randomness of spatial and temporal distribution of atmospheric refractive index.If the model coefficients can be adjusted in time according to the actual application environment,the correction effect of atmospheric refraction error may be improved effectively.The above research provides a theoretical basis for the inversion optimization and correction of atmospheric refraction error in this paper.Then,the optimization and correction method of atmospheric refraction error inversion based on mapping function method is studied.According to the flow chart of inversion method in practical application,the inversion problems are decomposed and summarized,and the problems are discussed one by one.The global sensitivity analysis method is used to analyze the model coefficients of the mapping function method,and the related technologies involved in the inversion optimization correction method of atmospheric refraction error,such as the inversion model,objective function and optimization method,are studied.According to the results of analysis: the model coefficient of the mapping function has the highest sensitivity to the correction effect of atmospheric refraction error,and improving the accuracy of can improve the accuracy of the correction of atmospheric refraction error.It is suggested that the mapping function method be degenerated into an inversion model containing undetermined parameters and zenith delay.The second-order norm of atmospheric refraction error correction residuals is used as the objective function of the inversion method,and the undetermined parameters are solved by particle swarm optimization algorithm.Finally,the inversion method is studied experimentally.By comparing the inversion method with the common atmospheric refraction error correction model and using the inversion method in the target height error correction case,the correction effect of the inversion method and the problems in the practical application are analyzed.According to the experimental results,the effects of inversion method are mainly concentrated in the dry part of atmospheric refraction error in lower elevation angle.For the wet part of atmospheric refraction error,it is difficult to adopt the strategy of adjusting the model coefficient,and other more effective methods should be adopted to improve the correction effect of refraction error.In addition,the inversion method should supplement the measured data in time and update the model parameters to improve the correction accuracy of the inversion method in the practical application.If necessary,the inversion model and objective function should be changed according to the actual conditions.