【作者】 刘荣建；

【导师】 洪振杰；

【作者基本信息】 温州大学 ， 应用数学， 2011， 硕士

【摘要】 2006年4月,中国台湾和美国合作的COSMIC卫星星座的发射成功,为反演电离层掩星提供了大量的观测资料。电离层中的不规则体和电离层的扰动,对卫星通讯、短波通讯和卫星导航定位,产生重要影响。无线电波在地球电离层中的传播容易发生色散、吸收和折射等效应。现有的研究表明,通过电离层(电子含量或电子密度)的异常扰动有可能探求地震前兆信息。对电离层的认识和探测,发展相应的预报业务,具有重要的应用价值和科学意义。本文讨论了传统的电离层掩星反演以及其它反演方法,本文的结构如下:1、简要地介绍了无线电掩星技术的发展状况、电离层结构及研究现状2、通过COSMIC掩星电离层观测资料L1和L2的相位组合,可以得到总电子含量TEC;再利用非掩星侧的辅助观测数据来校正TEC,以消除LEO卫星轨道高度以上的TEC;然后在电子密度局部球对称假设和信号直线传播近似下,利用Abel积分变换得到电子密度垂直廓线。3、Abel变换反演电离层方法是在球对称假设下进行的。电离层的非球对称分布给电离层电子密度反演带来误差。本文探讨了非球对称电离层反演方法,讨论了这些方法的可行性。4、介绍独立研发的电离层掩星反演软件,给出文件输入、文件输出接口。5、对本文工作做了简要总结和展望更多还原

【Abstract】 A constellation of six satellites, called COSMIC, was launched on 15 April 2006 from Vandenberg Air Force Base, California. And lots of ionospheric occultation data were provided from the COSMIC satellites. In the Earth’s ionosphere, radio wave propagation prone happen reflection, scattering, refraction and absorption. Ionospheric disturbances and irregularities can affect short-wave communications, satellite communications and satellite navigation. Therefore, there is very important to search the ionosphere.This thesis discusses the traditional inversion of ionospheric occultation and other inversion methods. The main works can be summarized as following:1. This thesis briefly describes the development of the Ionospheric Radio Occultation (IRO) technique, the structure and the current situation of the ionospheric.2. The relative total electron content TEC is obtained through the combination of COSMIC radio occultation ionosphreic measurements L1 and L2 phase; The TEC data are then calibrated by non-occultation observation data on the auxiliary side to remove portion of TEC above the LEO orbit altitude; The electron density profile can be retrieved from TEC by Abel integral transformation, with a spherically symmetric assumption of electron density and an approximation of signal straight-line propagation.3. The Abel inversion based on a spherical symmetry of the ionospheric electron density distribution is a traditional method for inversion of ionospheric occultation. However, the real ionosphere is not strictly spherical symmetry, which can cause error in inversion process of ionospheric occultation data. To reduce the error, this thesis discusses the other inversion methods, focusing on the feasibility of these methods.4. This thesis introduces the ourselves researching software of the inversion of ionospheric occultation, including input files and out files.5. Make a brief summary of the results.更多还原