Comparisons of GPS Troposphere Parameters Estimated at Rates from 1 to 1800 Seconds and Implications for Meteorological Applications

Half-hourly estimates of precipitable water (PW) from ground-based GPS have been ingested by operational weather models in the U.S., demonstrably leading to more accurate forecasts, for a number of years. Ongoing upgrades to communications infrastructure in the western U.S. have enabled many GPS stations to stream data in real time at rates up to 1 Hz. At a number of these real-time sites in southern California, we have deployed prototype Geodetic Modules that can perform onsite Precise Point Positioning with Ambiguity Resolution (PPP-AR) position and troposphere delay solutions and stream the results at up to 1Hz for earthquake early warning (EEW) and weather hazard applications. This approach enables the next phase of development that includes a software upgrade to calculate the GPS PW at the site to eliminate the single point of failure when performing the processing at a central processing location. This also enables delivery of the processed results to various remote and local users in a continuous stream with no delay. We compare the 1 second troposphere delay estimates with 5 minute and 30 minute estimates to assure consistency with previous results. In addition to the benefits of zero latency communication for weather forecasting, the approach may yield a deployable real-time PW device that could be beneficial as a source of real-time PW in field studies.