Monitoring of phase fluctuations of GPS signals in polar ionosphere

Dual frequency measurements of differential carrier phase of GPS L1 (fl=1.6 GHz) and L2(f2=1.2 GHz) signals have been used to study the storm-time development of phase fluctuations in Antarctic region. We used GPS measurements of the International GPS service (IGS) network stations of MCM4 (78°S, ¿~80°), CASI 66°S, ¿~80°), MAWI 67°S, ¿~71°), DAVI (68°S, ¿~75°). The phase fluctuations are caused by the presence of irregularities of different are in high latitude ionosphere. The standard GPS measurement provided global network are sampled with 30 s. The interval enables to detect the ionosphere irregularities with scale more than tenth kilometers. For analysis of the data the temporal variations of differential carrier phase GPS signals along individual satellite passes was used. In this report we present an occurrence phase fluctuations with scale times¿30 min. which were caused by large-scale irregularities with the size more than 100 km. The slow fluctuations of differential carrier phase characterize the spatial and temporal variations of TEC along individual satellite passes. The strong TEC fluctuation as an enhancement of TEC relative phon was found out in polar stations. The enhancement of TEC was bigger than 2¿10 time relative background, while the TEC increase to 10¿15 TECU in interval about 5¿10 min. The duration of such structures was up 10¿20min. It was observed during storm as well as during modrate geomagnetic activity. We attributed the structures as occurrence of polar patches. The intensity of TEC fluctuations increased during geomagnetic activity. on the 4¿5 hour satellite passes 3¿6 numbers strong and some weak patches ordinary were detected. As the measure of patch activity we used the rate of TEC on 1 min interval (ROT).