Table 1 Data processing models and strategies

Observations

Undifferenced ionosphere-free combination of GPS L1/L2, Galileo E1/E5a, BDS B1I/B3I observations

Observation noise

Pseudorange: 0.5 m; Carrier-phase: 0.01 cycles

PCO/PCV

igs14.atx for satellites and stations

Tropospheric delay

Global Pressure and Temperature (GPT) model with Global Mapping Function (GMF), hourly Zenith Total Delay (ZTD), and 24-h gradients (Boehm et al., 2007)

Earth rotation

Universal Time (UT1) is fixed; x- and y-pole coordinates, dx, dy, and Length Of Day (LOD) are estimated

Tidal displacement

International Earth Rotation Service (IERS) Conventions 2010, global tide Finite Element Solution 2014b (FES2014b) for ocean tides (Spiridonov and Vinogradova 2020)

Relativity effect

IERS Conventions 2010

Earth gravity

Earth Gravitational Model 2008 (EGM08) 12°

Perturbations

Sun, Moon, and planets in JPL Development Ephemeris 405 (DE405)

Solar radiation

ECOM1 5-parameters with a priori model for Galileo; ECOM2 9-parameters for GPS without a priori model; ECOM1 5-parameters for BDS-3 IGSO without a priori model; ECOM2 9-parameters for BDS-3 Medium Earth Orbit (MEO) with a priori model (Lou et al., 2014; Springer et al., 1999; Wang et al., 2018a; Yan et al., 2019)

Attitude model

GPS yaw attitude model by Kouba (2009, 2013) and Dilssner (2010); Galileo yaw model with metadata (EGSC, 2017); BDS-3 yaw-steering model (Lin et al., 2018; Wang et al., 2018b; Xia et al., 2019)