Regional Ionospheric Maps with Quad-Constellation Raw Observations as Applied to Single-Frequency PPP

Ionospheric delay is one of the most problematic errors in single-frequency (SF) global navigation satellite system (GNSS) data processing. Global/regional ionospheric maps (GIM/RIM) are thus vitally important for positioning users. Given coexistence multi-GNSS, integration quad-constellation observations essential improving distribution penetration points (IPPs) and increasing redundant compared with existing GIM products from IGS analysis center. In this paper, (GPS/GLONASS/Galileo/BDS) applied to set up RIM over Australia uncombined precise point (UC-PPP) a low-order spherical harmonic function. The generated RIMs then introduced ionosphere-corrected (IC) ionosphere-weighted (IW) PPP (IC-SFPPP IW-SFPPP) verify their performance terms accuracy convergence time. Taking CODE as reference, results show that mean root square (RMS) VTEC differences 0.867 TECUs, (referred ‘RIM4?) can improve RMS single-constellation mode at edge regional experiment area. application RIM4 BDS IC-SFPPP 18.38% improvement (from 100.47 cm 82.00 cm) 3D CODE-GIMs, whereas 35.36% enhancement 115.92 74.62 achievable during an active period. Moreover, if criterion time defined when horizontal vertical directions less than 0.3 m 0.6 20 consecutive epochs, IW-SFPPP significantly speed SFPPP; is, reduced by 52.7% 37 min 17.5 min), 37.2% 72.5 45.5 37.1% 62.0 39.0 min) north, east direction, respectively, 68% confidence level.