09:00 〜 09:15
[G06-3-03] Global and regional high resolution VTEC Representations using B-Splines and Kalman filtering
The project OPTIMAP is a joint initiative of the Bundeswehr Geoinformation Centre (BGIC), the German Space Situational Awareness Centre (GSSAC), the German Geodetic Research Institute of the Technical University of Munich (DGFI-TUM) and the Institute for Astrophysics at the University of Goettingen (IAG). The main goal of the project is the development of an operational tool for ionospheric mapping and prediction. The tool will consider all available observation techniques (GNSS, satellite altimetry, radio occultations and DORIS) which are sensitive for the ionosphere and provide global and regional VTEC products with a high spatial and spectral resolution within a two-level model (TLM).
Since the ionospheric observations from space-geodetic missions are distributed rather unevenly over the globe, an appropriate modeling approach has to be developed. Our approach is based on a two-level strategy with a global modeling part as the first and a regional modeling part as the second level. To be more specific, the global VTEC model contains moderate regional and spectral resolution, while in areas with a dense measurement distribution, a regional VTEC model with a higher resolution is set up.
The global VTEC model part is based on a series expansion in terms of polynomial B-Splines in latitude direction and trigonometric B-Splines in longitude direction whereas the regional model part is set up by polynomial B-splines for both directions.
In terms to avoid dependencies between the global and the regional models a data selection by means of a "thinning out" procedure, based on station positions, is applied. The two selected subsets of observations are exploited within multiple Kalman filtering processes which are running in parallel mode in order to estimate the unknown B-spline series coefficients. Additional technique-dependent unknowns such as the GNSS Differential Code Biases (DCBs) are considered. In this contribution we will present the first numerical results.
Since the ionospheric observations from space-geodetic missions are distributed rather unevenly over the globe, an appropriate modeling approach has to be developed. Our approach is based on a two-level strategy with a global modeling part as the first and a regional modeling part as the second level. To be more specific, the global VTEC model contains moderate regional and spectral resolution, while in areas with a dense measurement distribution, a regional VTEC model with a higher resolution is set up.
The global VTEC model part is based on a series expansion in terms of polynomial B-Splines in latitude direction and trigonometric B-Splines in longitude direction whereas the regional model part is set up by polynomial B-splines for both directions.
In terms to avoid dependencies between the global and the regional models a data selection by means of a "thinning out" procedure, based on station positions, is applied. The two selected subsets of observations are exploited within multiple Kalman filtering processes which are running in parallel mode in order to estimate the unknown B-spline series coefficients. Additional technique-dependent unknowns such as the GNSS Differential Code Biases (DCBs) are considered. In this contribution we will present the first numerical results.