Dual-frequency GPS single-point positioning error during the ionospheric irregularity

The existence of the ionospheric irregularity can affect the performance of GPS signal or receivers by causing cycle slip, loss of lock, or degrading the positioning error. One year observations in 2011 from one Internal GNSS Service (IGS) dual-frequency GPS receiver, located at Taoyuan, Taiwan, are used to analyze the positioning error during the existence of the ionospheric irregularity. ROTI is used to determine the existence of the ionospheric irregularity. 53 irregularity events occurred in 2011, and these events are classified according to the value of ROTI: weak irregularity event with ROTI <; 1, median irregularity event with 1 <; ROTI <; 3, and strong irregularity event with ROTI >; 3. The horizontal positioning error and the height error are calculated during each event and compared with the positioning errors on the quiet day as reference. The results showed that not all the irregularity events affected the positioning error even for the strong events. But the statistic results showed that most of the strong events degrade the horizontal and height error, and only few weak events affected the positioning accuracy of the dual-frequency.