Table 3 Strategies for real-time kinematic PPP
From: Comprehensive assessment of real-time precise products from IGS analysis centers
Items | Correction model or estimation strategy |
|---|---|
Satellites | GPS, Galileo, BDS and GLONASS |
Observations | Ionosphere-free code and phase combinations |
Satellite orbit and clock | Navigation message and SSR from different ACs |
Sampling interval | 30 s |
Cutoff elevation | 10° |
Observation weight | Pseudo range noise: 0.5 m; Carrier phase noise: 3 mm Elevation-dependent (based on sine of elevation) |
Phase-windup effect | Corrected according to Wu et al. (1992) |
PCO/PCV | GPS, Galileo and GLONASS: corrected with igs14.atx (Dawidowicz, 2018) BDS only correct Phase Center Offset (PCO) |
Relativistic effects | Corrected |
Solid tide | International Earth Rotation and Reference Systems Service (IERS) Conventions 2010 (Petit & Luzum, 2010) |
Ocean loading | IERS Conventions 2010 (Petit & Luzum, 2010) |
Pole tide | IERS Conventions 2010 (Petit & Luzum, 2010) |
Coordinates | Initial values are from Stand Point Positioning (SPP), process noise: 602 m2 /s |
Receiver clock | Initial value is from SPP, process noise: 602 m2 /s |
Troposphere | A priori model (Saastamoinen, 1972) and Global Mapping Function (GMF) (Boehm et al., 2006) are used and zenith wet delay is estimated as random walk noise. Initial value: 0.15 m, process noise: 1 × 10–8 m2/s |
Carrier-Phase ambiguities | Initial value: \({N}_{j}=\Phi -P+2\frac{{\lambda }_{j}^{2}}{{\lambda }_{1}^{2}}{I}_{1}\), j denotes frequency index, process noise: 0 (i.e., as constant) |