IntroductionPrecipitable water vapor (PWV) is an important parameter for characterizing the spatiotemporal variability of atmospheric water vapor. Accurate realtime PWV retrieval is essential for weather monitoring and extreme weather forecasting. Currently, the real-time PWV retrieval mainly depends on state space representation (SSR) correction products provided by the International GNSS Service (IGS). However, SSR products require a stable network connection and are vulnerable to data loss ca