New Adaptable All-in-One Strategy for Estimating Advanced Tropospheric Parameters and Using Real-Time Orbits and Clocks

Abstract

We developed a new strategy for a synchronous generation of real-time (RT) and near real-time (NRT) tropospheric products. It exploits the precise point positioning method with Kalman filtering and backward smoothing, both supported by real-time orbit and clock products. The strategy can be optimized for the latency or the accuracy of NRT production. In terms of precision, it is comparable to the traditional NRT network solution using deterministic models in the least-square adjustment. Both RT and NRT solutions provide a consistent set of tropospheric parameters such as zenith total delays, horizontal tropospheric gradients and slant delays, all with a high resolution and optimally exploiting all observations from available GNSS multi-constellations. As the new strategy exploits RT processing, we assessed publicly precise RT products and results of RT troposphere monitoring. The backward smoothing applied for NRT solution, when using an optimal latency of 30 min, reached an improvement of 20% when compared to RT products. Additionally, multi-GNSS solutions provided more accurate (by 25%) tropospheric parameters, and the impact will further increase when constellations are complete and supported with precise models and products. The new strategy is ready to replace our NRT contribution to the EUMETNET EIG GNSS Water Vapour Programme (E-GVAP) and effectively support all modern multi-GNSS tropospheric products.

Sensitivity of GNSS tropospheric gradients to processing options

“…The STDs represent the signal travel time delay between the satellite and the station due to neutral atmosphere and they are considered useful in Published by Copernicus Publications on behalf of the European Geosciences Union. numerical weather prediction (Järvinen et al, 2007;Kawabata et al, 2013;Bender et al, 2016) and reconstruction of 3-D water vapour fields using the GNSS tomography method (Flores et al, 2000;Bender et al, 2011). Brenot et al (2013) showed a significant improvement in IWV-interpolated 2-D fields when tropospheric gradients are taken into account.…”

Performance Evaluation of Troposphere Estimated from Galileo-Only Multi-Frequency Observations

“…The software has met the requirements for real-time multi-GNSS troposphere estimation for meteorological applications [25]. The tropospheric parameters in a high temporal resolution, including ZTDs, horizontal tropospheric gradients, and slant path delays, can be estimated in both real-time and near real-time processing modes [26]. Two estimators are supported: A forward Kalman filter for the real-time processing and a backward smoother to improve the precision of the troposphere [27] in the case of post-processing or near real-time.…”

Improving GNSS Zenith Wet Delay Interpolation by Utilizing Tropospheric Gradients: Experiments with a Dense Station Network in Central Europe in the Warm Season

“…We used the G-Nut/Tefnut software [15] for processing GNSS observations from GPS and GLONASS constellations. The software employed the Precise Point Positioning (PPP) method [16] and we utilized precise products for satellite orbits and clocks provided by the European Space Agency, ESA (http://navigation-office.esa.int/GNSS_based_products.html).…”