LAUSR

The present paper investigates GPS, GLONASS, and Beidou observables from the Multi-GNSS Experiment (MGEX) network of stations in the East Asia region. Precise Point Positioning (PPP) estimates, Dilution of Precision (DOP), Slant Total Electron Content (STEC), and Zenith Total Delay (ZTD), along with their prediction from the Singular Spectrum Analysis (SSA), were studied to analyze and understand their effectiveness on the overall positioning accuracy over the region. The analysis confirms that the PPP accuracy does not solely depend on the DOP values, but is also affected by seasonal changes or partial corrections of the ionospheric and tropospheric delays. The accuracy is improved by approximately 70% for the GPS (G), GPS+GLONASS (GR), and GPS+GLONASS+Beidou (GRC) constellations after applying the SSA method. The GNSS-derived STEC and ZTD values were also predicted with the SSA methods to evaluate the trustworthiness of the approach for mitigation of atmospheric errors. The results show that the STEC and ZTD seem to be in perfect agreement with the SSA model. The technique could be applicable for improved navigational measurements augmenting other available constellations such as the Galileo, IRNSS, and QZSS, as well as satellite-based augmentation systems across the globe.