Establishment of polynomial regional ionospheric delay model by using GNSS dual-frequency combined observations

Abstract

The Global Navigation Satellite System (GNSS) is currently one of the more effective observation methods for measuring the Total Electron Content (TEC) of the ionosphere. At the same time, the ionospheric delay is also one of the most serious error sources affecting the accuracy of GNSS technology. The establishment of the ionospheric model can eliminate and weaken the delay error and improve the accuracy of navigation and positioning. There are many existing ionospheric delay models. For small regions, the ionospheric delay error is usually polynomial model, but the parameters and precision of the polynomial model are not studied deeply. In this paper, by means of Continuously Operating Reference Station (CORS) and precise ephemeris, the data is preprocessed and the combined observation of the P code pseudo-ranges is smoothed by combined observations, so that polynomial ionospheric delay model with different parameters and joint hardware delay of receiver and satellite are generated. And then the accuracy of the model is analyzed and evaluated, it can be concluded that the parameter value of the polynomial regional ionospheric delay model (i=2,k=3) is appropriate, the Klobuchar model can correct the ionospheric delay error from 2.5m to 3.5m, the polynomial model can reach 0.263m or even higher, especially in today’s multi-frequency and multi-satellite system development.