Ionospheric effects on relative positioning within a dense GPS network

• DOI: 10.1007/s10291-011-0212-1
• Publication Date: 2011-03-01T18:07:52Z
• Authors: S. Lejeune; G. Wautelet; R. Warnant
• Keywords: 13. Climate action; 01 natural sciences; 0105 earth and related environmental sciences

Local variability in total electron content can seriously affect the accuracy of GNSS real-time applications. We have developed software to compute the positioning error due to the ionosphere for all baselines of the Belgian GPS network, called the Active Geodetic Network (AGN). In a first step, a reference day has been chosen to validate the methodology by comparing results with the nominal accuracy of relative positioning at centimeter level. Then, the effects of two types of ionospheric disturbances on the positioning error have been analyzed: (1) Traveling ionospheric disturbances (TIDs) and (2) noise-like variability due to geomagnetic storms. The influence of baseline length on positioning error has been analyzed for these three cases. The analysis shows that geomagnetic storms induce the largest positioning error (more than 2 m for a 20 km baseline) and that the positioning error depends on the baseline orientation. Baselines oriented parallel to the propagation direction of the ionospheric disturbances are more affected than others. The positioning error due to ionospheric small-scale structures can be so identified by our method, which is not always the case with the modern ionosphere mitigation techniques. In the future, this ionospheric impact formulation could be considered in the development of an integrity monitoring service for GNSS relative positioning users.