Study on the Characteristics of the GNSS Bias in Middle and Low Latitude Ionosphere TEC Calculating

With the technical application and development of GNSS, the TEC data, the total electron content of the ionosphere, has been measured routinely and used widely in ionosphere studies. As one of the important parameters of the ionosphere, ionosphere TEC is widely used whether in ionosphere research or in satellite navigation. Therefore, it is very important to accurately measure, calculate, evaluate and analyze TEC. So the study on the GNSS bias is often limited to single type of error calculation and lack of comprehensively quantitative results and statistical analysis. We integrated and comprehensively investigates and calculates the ionosphere TEC and the bias of the satellites and stations, through the accumulation of a large number of muti-source measured data and the results of ionospheric model. The GPS TEC data used in this paper comes from different area stations. These stations are near three meridians-120ºE,15ºE, 70ºW and on mid- latitude and low-latitude. The error will be classified by the generating and influencing sources and statistical analyzed. We summarized the distribution and variation of the characteristics of types of the satellite bias and the station bias and verify the accuracy of the reliability of error calculation. We found a better compensation algorithm of ionosphere TEC suitable for GNSS observations. We provided the theoretical basis and applicaton support to improve the accuracy of the ionosphere TEC data in China.