Comparison and Analysis of Ionospheric Delay Correction Methods Based on BeiDou GEO

Ionospheric delay is the most important factor affecting the accuracy of navigation and positioning. The BeiDou satellite navigation system uses the Klobuchar model to correct the ionospheric delay error of single frequency receiver users. For dual frequency receivers, the ionospheric delay value can be calculated by using pseudo range observations data of different frequency signals.. In order to compare the correction effect of ionospheric delay of two methods in Tianjin area, the satellite measured data collected by NovAtel GPStation6 receiver (GNSS Ionospheric Scintillation and TEC Monitor Receiver) are used to calculate. Taking the global ionosphere grid data published by the International GNSS Service (IGS) as a reference, the correction effect of the two methods are compared and analyzed. The results show that in the Tianjin area, the ionospheric delay calculated by the dual frequency observations is more accurate than the Klobuchar model, and the average daily correction is 82.11％ of IGS, 9.48％ higher than that of Klobuchar model.