利用GPS计算TEC的方法及其对电离层扰动的观测

在总结用ＧＰＳ研究电离层电子总量ＴＥＣ的数据处理方法基础上，分析了利用伪距观测量和载波相位观测量计算电离层ＴＥＣ的特点及误差来源．在处理过程中考虑了卫星的硬件延迟偏差，分析了应用ＩＲＩ模型进行接收机硬件延迟偏差修正的可能性，发现利用少量ＧＰＳ数据和ＩＲＩ模型修正接收机硬件延迟偏差有一定的困难．最后，利用一些ＧＰＳ观测数据有针对性地研究了电离层对若干次扰动事件的响应．包括一次大的太阳耀斑期间的电离层ＴＥＣ变化、一次较典型的电离层行扰以及日食期间的电离层ＴＥＣ的相对变化等电离层物理问题．结果表明，利用该方法计算ＴＥＣ的精度可满足电离层扰动现象的研究．

METHOD OF CALCULATING TEC WITH GPS DATA AND ITS APPLICATION TO THE IONOSPHERIC DISTURBANCES

The methods of calculating total electron content （TEC） by using of the dual- frequency GPS receiver are summarized in this paper. Error sources of calculating TEC using pseudorange and carrier-phase are analyzed. Considering the relation between the GPS SNR（signal-noise-rate） and elevation of the GPS satellites, the method of calculating absolute TEC by using pseudorange and carrier-phase simultaneously was particularly discussed and compared with that usually used to calculate absolute TEC by algebraic sum. The instrumental bias of satellite and receiver and their removing method are also analyzed. In order to determine the receiver bias, the GPS TEC result and the IRI model TEC result are compared. It is concluded that correcting the receiver instrumental bias using only little GPS data and IRI model is difficult instead, statistics are necessary. With the method presented in this paper based on the above discussions, the responses for ionospheric perturbations were studied using data from four China GPS stations with emphasis on the ionospheric Perturbations such as the effects of solar flare, TIDs and solar eclipse in March 9th 1997. The results show that the accuracy of the method is sufficient in studying the ionospheric disturbances.