Study of Ionosphere Using GPS Data and its Application to Analysis About Earthquake

To obtain VTEC as well as DCB, a method is developed by using ground-based GPS data with multiple-arc method and Kriging interpolation. Assisted by multiple-arc method, VTEC was calculated every 30 minutes as local variables, and DCB was calculated every day as global variables. Kriging method, taking the spatial information of VTEC into account, helps us to establish a 2D model and get DCB of both satellites and receivers. The result shows itself reliably in comparison with IGS result, but more stable and precise in resolution. Meanwhile, grounded on 3-variable spline basis function, we unfold electron density into a linear combination of a set of grid point. With its contribution, CT result of ionospheric electron density was made by MART. This result is consistent with CHAMP result get by occultation method. These two ways are applied to the data of Yangtze River triangle region in May, 2008 when the shocking earthquake happened in Wenchuan. A simple statistic analysis reveals the response of ionosphere to the signal associated with earthquake but occurred before it.