Impact of using products from different IGS analysis centers on PPP solution quality : A GNSS campaign in Oran, Algeria

Precise Point Positioning (PPP) is widely used in high-precision GNSS applications, and its performance depends primarily on the orbit and clock products provided by the International GNSS Service (IGS). This study evaluates the impact of using products derived from different IGS Analysis Centers (ACs) on PPP solution quality, using data collected during a GNSS campaign conducted to study an active fault in Oran, Algeria. Data from multiple GNSS stations, located in both open-sky and challenging/constrained environments, were processed using static and kinematic PPP modes with various IGS ACs products. As long-duration observations showed no significant differences, only 30-minute sessions were processed to provide a clear evaluation of solution quality. Position uncertainties, carrier-phase residuals, and kinematic position repeatabilities were analyzed to assess the quality of the solutions. To ensure a fair comparison between the ACs’ products, the analysis was limited to products with the same number of observed satellites and a consistent 30-second clock rate. Furthermore, to include the maximum number of ACs, both OPS and MGEX products were considered, and only GPS and GLONASS satellites were used, as these are provided by the majority of IGS ACs.

Our analysis of epoch-wise phase residuals across multiple IGS ACs, indicates that the residual behavior is remarkably consistent across stations. Exceptions occur at more challenging stations, where some ACs’ solutions, such as GRG, exhibit slightly lower residuals quality. Similarly, for solution repeatability, most ACs products provide comparable results, with GRG again performing slightly worse, particularly in the vertical component showing an RMS repeatability of approximately 30 mm compared to 23 mm at the challenging station AGF21. In terms of positional uncertainties, all solutions demonstrate good horizontal and vertical precision, with values ranging from 1 to 4 mm. Among the ACs, COD (MGX), GFZ, and GRG show marginally better horizontal performance, while JGX performs slightly worse in both components. Vertical uncertainties benefit as well, with improvements of about 4 to 6 mm observed when using COD (MGX), GFZ, and GRG products, especially at the more challenging stations.