GNSS Data Processing and Validation of the Altimeter Zenith Wet Delay around the Wanshan Calibration Site

The Wanshan calibration site (WSCS) is the first in-situ field for and validation (Cal/Val) of HY-2 satellite series in China. It was built December, 2018 began business operation 2020. In order to define an accurate datum Cal/Val altimeters, permanent GNSS station (PGS) data WSCS observed on Zhiwan (ZWAN) Wailingding (WLDD) islands were processed using GAMIT/GLOBK software a regional solution, combined with 61 stations distributed nearby, collected from Research Center, Wuhan University (GRC). Hector used analyze trend North (N), East (E), Up (U) directions six different noise models criteria maximum likelihood estimation (MLE), Akaike Information Criteria (AIC), Bayesian (BIC). We found that favorite white plus generalized Gauss–Markov (WN + GGM), followed by (GGM). Then, we compared PGS velocities each direction Scripps Orbit Permanent Array Center (SOPAC) output parameters there good agreement between them. PGSs had N, E, U −10.20 ± 0.39 mm/year, 31.09 0.36 −2.24 0.66 mm/year WLDD, −10.85 0.38 30.67 0.30 −3.81 ZWAN, respectively. defined altimeters as professional site. Moreover, zenith wet delay (ZWD) coastal sub-regional solutions calculated validate microwave radiometers (MWRs) Jason-3, Haiyang-2B (HY-2B), Haiyang-2C (HY-2C). A solution 19 continuous operational reference (CORS) Hong Kong Geodetic Survey Services derive ZWD MWRs altimeters. radiosonde-derived solutions. difference them −7.72~2.79 mm RMS 14.53~18.62 mm, which showed consistency two. PGSs’ MWRs. To reduce land contamination MWR, determined distances 6~30 km, 16~28 18~30 km HY-2B, HY-2C, differences HY-2C −2.30 16.13 9.22 22.73 −3.02 22.07