The effects of ionospheric disturbances on the accuracy of GPS radio occultation bending angle and temperature

Based on MSIS90 atmospheric and 3D NeUoG ionospheric models, three types of ionospheric disturbances, i. e. ionospheric storm, traveling ionospheric disturbance (TID) and ionospheric trough were simulated, and their effects on bending angle residual ionospheric errors (RIEs) and temperature accuracy were analyzed. The results show that under high solar activity level, the bending angle RIE and its standard deviation can reach 1.5 μrad and 0.9 μrad, in the impact height range of 35~50 km; 4 μrad and 1.4 μrad, respectively, in the impact height range of 15~35 km. The ionopsheric storm and trough can enlarge the bending angle RIE standard deviations by more than 20 times, and TID can enlarge the bending angle RIE standard deviations by several times. Under the influence of ionospheric disturbances, temperature errors can reach 8 K and can pollute the GPS RO daily-mean and month-mean observations. Hence, it is desirable to develop ionospheric correction algorithms; the temperature outliers caused by ionospheric disturbances should be removed according to ionospheric monitoring results.