US‐TEC: A new data assimilation product from the Space Environment Center characterizing the ionospheric total electron content using real‐time GPS data

摘要: [1] The potential of data assimilation for operational numerical weather forecasting has been appreciated many years. For space it is a new path that we are just beginning to explore. With the emergence satellite constellations and networks ground-based observations, sufficient sources now available make application techniques viable option. The first product at Space Environment Center (SEC) utilizing techniques, US-TEC, was launched as test in November 2004. US-TEC characterizes ionospheric total electron content (TEC) over continental United States (CONUS) every 15 min with about 15-min latency. based on Kalman filter scheme driven by network real-time GPS stations. includes map vertical TEC, an estimate uncertainty map, departure TEC from 10-day average particular universal time. In addition, files provided line-of-sight all satellites view CONUS information can be used improve single-frequency positioning providing more accurate corrections signal delay, or initialize rapid integer ambiguity resolution schemes dual-frequency systems. Validation indicates accuracy between 2 3 units (1 TECU = 1016 el m−2), equivalent less than 50 cm delay L1 frequencies, which promises value users. This step along will likely lead major improvement forecasting, paralleling advances achieved meteorological forecasting.