电离层斜向返回探测的反演研究

The oblique backscatter sounding is a powerful tool for detecting the ionosphere, and it can be used to monitor the ionosphere continuously at a remote distance. The ionospheric parameter inversion of backscatter ionograms is an important means of studying the ionosphere and of improving the performance of many modern radio systems.This project discusses the inverse problem of the ionospheric parameters by applying the inverse theory, and develops a new inverse method for this problem, trying to get over the difficulties of instability and non-uniqueness. Firstly, follow a line of investigation to the inverse theory, the reasons bringing on these difficulties are analyzed for the quasi-parabolic (QP) layer model inverse problem, and the keys to the inverse problem of backscatter ionograms is directed; An inverse method using Genetic Algorithm (GA) is also developed for the QP layer model. The results show primarily the advantages of this method in the inversion of backscatter ionograms. The inverse model for 2-dimensional ionosphere is established by using the inverse theory and the Tikhonov regularization method. The Genetic Inverse Method is applied to the problem of interest and is tested against the model data with noise. The studies in this paper demonstrate that it is effective to make use of the inverse theory/method to overcome the instability and non-uniqueness for the inverse problem of backscatter ionograms, and that the Genetic Inverse Method is available and efficient for obtaining stable and reasonable results.

本项目把逆散射理论基本原理应用到电离层斜向返回探测反演研究中，利用斜向返回散射数据，借鉴地震波反演中较为成功的理论方法，进行电离层非线性反演理论和实验研究，力求建立电离层反演的新方法，解决电离层返回斜测反演的唯一性和不稳定性问题。这对电离层反演理论研究、电离层实时预报及其在无线电系统中的应用等都有很重要的意义。