First Zenith Total Delay and Integrated Water Vapour Estimates from the Near Real-Time GNSS Data Processing Systems at the University of Luxembourg

Since June 2011, the University of Luxembourg has started in collaboration with the University of Nottingham a PhD project entitled “The Potential of Precipitable Water Vapour Measurements using Global Navigation Satellite Systems in Luxembourg (PWVLUX)”, which is funded by the Fonds National de la Recherche (FNR) Luxembourg. The research objectives of the project are to study the potential for improvements in short-term weather forecasts and long-term climate variability for Luxembourg and the Greater Region by inclusion of the observations from Global Navigation Satellite Systems (GNSS) in the existing techniques. To achieve the research objectives, systems are being set up at the University of Luxembourg which process ground-based GNSS data for the provision of zenith total delay (ZTD) and integrated water vapour (IWV) estimates in real-time, near real-time and post-processing modes. Through collaboration with the Administration du cadastre et de la topographie (Luxembourg) and the Service public de Wallonie (Belgium), the coverage of the available GNSS permanent networks is improved over the primary project area, although also data from other European and global networks are processed. The meteorological analysis of the PWVLUX products is supported through collaborations with the Meteorological Service of the Administration de la navigation aérienne and the EUMETNET project E-GVAP. In this study we present the first ZTD and IWV estimates obtained from the near-real time processing systems in development at the University of Luxembourg. In a preliminary evaluation we compared their performance to some state-of-the-art systems already in operation and found that the ZTD estimates agree up to a few millimeters and the IWV estimates agree at the sub-millimeter level.