Multi-system GNSS Ionospheric Sounding And EOF Time Series Analysis

Compared with traditional ionospheric monitoring technology,GNSS TEC has the characteristics of high inversion accuracy,wide coverage,and continuous observation all-weather.Although GNSS ionospheric monitoring technology has been developed for more than two decades,there are still many problems that require us to conduct more in-depth exploration.The current exploration of multi-mode GNSS ionospheric research has been deepened with the continuous development of GPS,GLONASS,GALILEO and BDS satellite navigation systems,but at the same time the progress of global positioning systems has also brought more to multimode GNSS ionospheric exploration.Challenge.The ionosphere is an important part of the space atmosphere,and it is of great significance to study the extraction of ionospheric data under multimode GNSS systems.Among them,the determination and use of the DCB value of the inter-code deviation has become the top priority of the ionospheric extraction research.In this paper,the algorithm for obtaining DCB under the multi-mode GNSS system is researched,using a large amount of measured observation data,based on the establishment of the multi-mode GNSS ionospheric TEC extraction model,the accuracy and reliability of the calculation results are analyzed,and the extracted Ionospheric TEC parameters were analyzed by climatological characteristics and empirical orthogonal model(EOF)time series analysis.The main content of this article mainly includes the following aspects:(1)The theory and method of using GNSS observations to extract ionospheric TEC parameters are summarized.The effect of carrier phase smoothing pseudorange is discussed and different estimation strategies of GLONASS satellite DCB are compared.(2)Realize the multi-mode GNSS satellite and receiver DCB parameter estimation algorithm.Compared with the single system estimation method,the DCB extracted by the multi-GNSS system is closer to the IGS product.(3)The DCB of IGS stations at different latitudes in January 2015 is calculated,and the accuracy and stability of the satellite and receiver DCB estimation results are comprehensively evaluated.(4)Based on DCB parameter estimation,the extraction of ionospheric TEC parameters is realized.Calculated the 11-year TEC data of BJFS station and analyzed the climatological characteristics.(5)Using the TEC data of IGS GIM products,based on the EOF method,the characteristics of ionospheric TEC changes with latitude at different latitudes are analyzed,as well as the spatial change characteristics of ionospheric TEC parameters in China and nearby regions.