Abstract:

In this paper, the algorithm of wide area augmentation system (WAAS) ionospheric grid correction was tested using 15 GPS stations’ observational data. The span of data was from July 1 to 8 and from July 14 to 18, 2000, which represented quiet and disturbed geomagnetic conditions respectively. The paper discussed algorithmic accuracy and the emphasis was laid on the different latitude users and the stormy conditions. Using geostatistics method, this paper further analyzed the spatial correlation of ionospheric grid errors distribution in term of integrity and availability. The results show that precision is high for user stations in the middle-high latitudes with the average of around 0.4 meters，but it is relatively decreases for the lower latitude. The algorithm prediction error is larger under ionospheric stormy conditions, which is more prominent for the stations in the low latitudes. Correlation of residual error decreases with the great circle distance between pierce points increasing. For the ionospheric quiet behaviors residual error is small and correlation is high between neighboring errors, but it is the opposite for the storm time.

Key words: LAYOUT-GRID-MODE: line, FONT-FAMILY: 'Times New Roman', mso-fareast-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-bidi-font-weight: bold">WAAS, magnetic storm, precision, correction error, correlation