The Evaluation of Ground-Based GNSS Tropospheric Products at Geodetic Observatory Pecný

Abstract

The Geodetic Observatory Pecný (GOP) has developed and operated near real-time solutions for precise estimation of zenith total delays (ZTD) using data from the Global Navigation Satellite Systems (GNSS) permanent stations since 2001. The GOP tropospheric products have been assimilated into numerical weather prediction (NWP) models operated by Meteo France and the UK Met Office and have been exploited in various ways by several other meteorological institutions. Over the last 3 years new developments consisted in the implementation and the assessment of (a) global hourly ZTD product, (b) regional ZTD products utilizing a common processing of the United States’ GPS and the Russian GLONASS data, (c) real-time ZTD product. Original and new tropospheric products were evaluated with respect to reference ZTDs provided by the International GNSS Service (IGS) and the IAG Reference Frame sub-commission for Europe (EUREF). Near real-time ZTD estimations from the network approach can be characterized by a mean bias below 2 mm and a mean standard deviation of 3–6 and 3–8 mm for regional and global analysis, respectively. The quality of ZTDs from the global analysis in Europe is highly consistent with those from the regional products. A half-year evaluation of the real-time ZTD production, using the Precise Point Positioning strategy and the IGS real-time orbit and clock products, resulted in the standard deviations below 10 mm and the biases up to 20 mm. The real-time processing strategy and software are still under development and we expect further improvements.