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https://www.ias.ac.in/article/fulltext/jess/121/04/0989-0999

Uncombined precise point positioning (U-PPP); regional ionospheric delay; phase-smoothed pseudorange (PSP); continuous operation reference system (CORS); interpolation; single-frequency PPP (SF-PPP).

A new method for the calibration of regional ionospheric delay based on uncombined precise point positioning (U-PPP) is proposed in this study. The performance of the new method was comparatively validated in terms of its accuracy and robustness with respect to the phase-smoothed pseudorange (PSP) method through two short-baseline experiments. Accuracy of the PPP-derived ionospheric delays was further assessed by interpolating them to a user station to perform single-frequency simulated kinematic PPP. Two 24-hr period datasets of four continuous operation reference system (CORS) stations were analyzed, collected during calm and disturbed ionospheric conditions, respectively. The single-frequency GPS observables from a user station, that were a-priori corrected by the interpolated ionospheric delays, were utilized to implement single-frequency PPP (SF-PPP). The results show that interpolation accuracy is better than 1 dm and, with the proposed method, is less affected by the ionospheric activity; meanwhile, positioning accuracy of SF-PPP was 4 ∼5 cm (horizontal) and better than 1 dm (vertical). For comparison, two reference SF-PPP solutions were also obtained, in which the ionospheric delays are eliminated either by forming semi-combination observations or by using global ionosphere maps (GIM) model values; in both cases the positioning accuracy was only 4 ∼7 dm (horizontal) and 1 m (vertical). These results provide a further demonstration of the performance of PPP-based regional ionospheric calibration in the parameter domain.

Li Wei^{1 2} Cheng Pengfei² Bei Jinzhong² Wen Hanjiang² Wang Hua^{1 2}

1. School of Geodesy and Geomatics, Wuhan University, Wuhan 430 079, China.
2. Chinese Academic of Surveying and Mapping, Beijing 100 830, China.

Published

August 2012

Manuscript received

7 June 2011

Manuscript revised

6 February 2012

Accepted

7 February 2012