Product Description

DLR's TEC maps for the European region provide information about vertical TEC (VTEC) derived from groundbased GNSS measurements with a latency of not more than 5 minutes and an update rate of 15 minutes. The maps cover the region between 30°N - 72°N and 30°W - 50°E with 2° in latitudes and 2° in longitude spatial resolution. The new beta version product uses a new processing chain. The product is currently provided for test purposes without validation.

This TEC map is generated from ground based GNSS measurements assimilated into an empirical TEC model. GPS dual-frequency data is acquired as input from different providers in real-time, e.g. via the German Federal Agency for Cartography and Geodesy in Frankfurt. This data is preprocessed in order to derive calibrated slant TEC (STEC) and to update the coefficients of the Neustrelitz Total Electron Content Model (NTCM) serving as ionospheric background. Subsequently the calibrated STEC measurements are assimilated into NTCM (cf. Jakowski et al., 2011). The TEC is provided in TEC units (10^16 electrons per square meter) for a shell-height of 400 km.

Every 5 minutes a VTEC matrix with an ionospheric grid point spacing of 1° latitude x 1° longitude is generated and stored in ASCII format. Data is provided here with 15 minutes updated rate. Higher temporal resolution can be provided on request.

This product can be applied to help to improve the accuracy during GNSS positioning. Related validations can be found for instance in Minkwitz et al. (2014). The quality of the TEC map depends on the errors of the GNSS measurements. These errors are monitored through the production pipeline and displayed in a TEC error map. This TEC error map is provided as quality information along with the product.

Jakowski, N., C. Mayer, M. M. Hoque, and V. Wilken (2011), Total electron content models and their use in ionosphere monitoring, Radio Sci., 46, RS0D18, doi:10.1029/2010RS004620.

Minkwitz, D., Gerzen, T., Wilken, V. et al. (2014), Application of SWACI products as ionospheric correction for single-point positioning: a comparative study, J Geod., 88: 463. https://doi.org/10.1007/s00190-014-0698-8