Simulation of Ionospheric Higher Order Effects in Navigation Signals Based on Ray Tracing

The ionosphere is an important error source for GNSS. In this paper, in order to study the effect of ionospheric higher-order effects on the extraction of ionospheric tilted total electron content, the dual-frequency and tri-frequency differential extraction STEC methods are simulated based on the simulated data of navigation signals. Firstly, the propagation process of the navigation signal in the ionosphere is simulated by ray tracing method, and then the simulations of dual-frequency and tri-frequency differential extraction of STEC are carried out under the Nequick ionospheric model, respectively. The simulation results show that the ray-tracing method can simulate the propagation process of navigation signals in the ionosphere more realistically. Compared with the dual-frequency differential STEC extraction method, the triple-frequency differential STEC extraction method can eliminate the ionospheric second-order effect more effectively and improve the STEC extraction accuracy.