Abstract: In order to improve the accuracy of GPS ionospheric signal error processing, a third-order tri-band correction model of GPS ionospheric refraction error is constructed based on the second-order three-frequency correction model of GPS ionospheric refraction error, and verify the accuracy of the model. The experimental results show that the accuracy of the third-order refraction error is 58.3% in the second-order three-frequency correction model of GPS ionospheric refraction error. In the third-order tri-band correction model of GPS ionospheric refraction error, The correction accuracy is 98.8%, and the correction accuracy of the third order refraction error of GPS ionospheric refraction error is improved by 40.5%. In the path delay correction (phase delay, group delay), the path delay of the third-order three-frequency correction model is different from that of the second-order three-frequency correction model. The phase delay correction is increased by about 3.01×10^-7 m, group delay correction is reduced by about 3.45×10^-7 m, and the ionospheric path delay is controlled to verify the feasibility of the model.

Key words: GPS, ionospheric refraction error, phase delay, group delay, third-order three-frequency correction model