The performance of SF-PPP corrected by different ionospheric models

Ionospheric delay can seriously affect the positioning accuracy of single-frequency global navigation satellite system (GNSS) receiver. Thus, this paper assessed the positioning error of single-frequency GNSS receiver corrected by four commonly used ionospheric delay correction methods, i.e., broadcast ionospheric correction models (strategy 1), time-rotation interpolation of Global Ionosphere Map (GIM) considering the variation of the position for the sun (strategy 2), GIM corrected by ionospheric mapping function (strategy 3), and half-sum correction model (strategy 4). Meanwhile, the correction results of different methods for the single-frequency precise point positioning (SF-PPP) were evaluated by using the data collected by ground-based GNSS stations over different latitudes on solar condition days. The assessment results were listed as follows. 1) The positioning error of SF-PPP corrected by the half-sum correction model was the best, then was the ionospheric delay corrected GIM. The positioning error corrected by broadcast ionospheric model was the worst. 2) On different solar condition days of each strategy, the positioning error for low-latitude stations was the largest, the was high-latitude stations. The positioning error for mid-latitude stations was the smallest. 3) The horizontal positioning error of strategy 2 and strategy 3 was about 0.150 m over different latitudes on different solar activity periods, while the 3D positioning error is about 0.700 m. The corresponding errors were about 0.100 m and 0.500 m for strategy 4.