A New Grid Model for the Vertical Correction of Zenith Hydrostatic Delay for China

摘要

Tropospheric delay is an important error source in GNSS (Global Navigation Satellite System) navigation and positioning, and its variation in the vertical direction is much greater than that in the horizontal direction. Some shortages still exist in current zenith hydrostatic delay (ZHD) vertical stratification models for China, such as only single gridded data is used for modeling. To address those of drawbacks, a new approach, the sliding window algorithm, is proposed to develop the ZHD vertical stratification model. In this paper, the ZHD layered profiles information calculated by MERRA-2 (second Modern-Era Retrospective analysis for Research and Applications) data integration with high spatial and temporal resolution from 2012 to 2016 are used to develop the ZHD vertical stratification grid model for China (named as CZHD-H model). The accuracy of CZHD-H model is verified with radiosonde data in 2017 as reference values in comparison with the canonical GPT2w model in spatial interpolation for GGOS (Global Geodetic Observing System) gridded ZHD. The results show that CZHD-H model maintains better performance in spatial interpolation for GGOS gridded ZHD. CZHD-H model has improved by 24% and 23% respectively compared to GPT2w-l and GPT2w-5 models in spatial interpolation for GGOS gridded ZHD against surface ZHD calculated from radiosonde profiles over China. Therefore, the CZHD-H model has well vertical correction performance for China, which shows significant application in GNSS high-precision positioning.