Abstract: By means of computer simulation,this paper presents the results of the ionospheric effects on the pseudorange differential positioning in a single frequency satellite navigation system. The pseudorange differential positioning can calibrate the error of ionospheric time delay, but the ealibrating accuracy varies with the difference between the obliquity factors of the user to a satellite and the reference station to the same satellite.Thus, an improving pseudorange differential method is proposed. Simulation results show that the method is obviously effectual.

Key words: satellite-radio navigation, ionospheres, time delay