Machiel Bos, Paul Crocker, Rafael Couto, RuiFernandes, Rui Cardoso, Hugo Valentim, JoséManteigueiro, Fábio Pereira and André Rodrigues

C4G/UBI (Consortium for Geosciences, University ofBeira Interior), Covilhã, Portugal

The C4G/UBI contribution for the EPOS GNSS Products Dissemination

Europe is covered by a few thousand GNSS stations, maintained by different agencies with different technical and scientificobjectives. Many of these are part of regional networks to provide support for geo-referencing applications such as surveying. Oneof the objectives of the European Plate Observing System (EPOS) project is to collect all these GNSS data, perform quality control,harmonize the format and present the data and their derived products at a data & product portal, see https://www.epos-ip.org/tcs/gnss-data-and-products, all in close collaboration with EUREF. We present here the efforts carried out by C4G/UBI in theframework of the EPOS project to support the harmonization and dissemination of products: position time series, velocity fields, andstrain rate maps.

Abstract

The GNSS product portal within EPOS

The GNSS products are generated by EPOS/EUREF Analysis Centres:• CNRS-UGA (Université Grenoble Alpes, France)• INGV (Istituto Nazionale di Geofisica e Vulcanologia - Centro Nazionale di

Terremoti, Rome, Italy)• BFKH (Department of Geodesy, Remote Sensing and Land Offices - Government

Office of the Capital City Budapest)• WUT (Department of Geodesy and Geodetic Astronomy, Warsaw University of

Technology, Poland)• ROB (Royal Observatory of Belgium, Belgium)• LM (Lantmäteriet - the Swedish mapping, cadastral and land registration

authority)

CNRS-UGA and INGV will produce dedicated daily solutions for all EPOS stations,which will be combined by BFKH with the EUREF solutions produced by WUT, Poland(based on several individual EUREF Analysis Centers) and in the reference framematerialization provided by ROB. At velocity level, BFKH will compute a velocity fieldincluding stations for which data are not made available (EUREF densified solution).CNRS-UGA and INGV will also produce dedicated velocity field based on theirsolutions. The latter will also compute a combined velocity field for the EPOSstations. Finally, LM will be responsible for the operationalization of the computationof strain rate maps.

https://gnssproducts.epos.ubi.pt

Products provided

Fig 1. The left panel shows the flow of GNSS data inside the GNSS Thematic core servicewhich makes use of GLASS (GNSS Linkage Advanced Software System). The products can beobtained directly by users by visiting the product portal or by using its GLASS – APIenvironment. The latter is used to integrate GNSS data in the overall EPOS portal (see rightpanel).

Flow of GNSS EPOS products

The GNSS EPOS product portal

Validation of GNSS EPOS products

Fig 2. The flow of GNSS EPOS products to the product portal. EPOS/EUREF analysis centresdeposit their products on our sftp-server. The position coordinates/time series aresubjected to a quality control and only afterwards inserted in our database (DB). Thisdatabase is queried by the product portal using the GLASS Framework. Fig 3. C4G/UBI will intervene in this scheme by

validating the velocity solutions computed by thedifferent groups. This is done by 1) comparing thesolutions produced by the different methodologies[left panel]; and 2) analyzing each time series byscreening for outliers and ensuring that the jumps inthe time series are being detected using Hectorsoftware. The same software is used to compute thepower spectrum of the residuals to detect abnormalnoise behavior [top panel].

Fig 4. The GNSS product portal that will be maintained by C4G/UBI in the future in theframework of EPOS-ERIC (operational phase). The daily positions and velocities can bedirectly queried and afterwards downloaded in various formats such as PBO, MIDAS andHector [left image]. Another format is XML which is more convenient for IT purposes. Thestrain rate maps are also displayed on a map [right image]. The download can be donemanually using the online Graphical Web Application or automatically via scripts and otherthird party applications using Restful API’s.

NOW

Current Timeline and Status

Fig 5. The provision of Products is already available through the Products Gateway,however this is still a prototype and some reserves should be taken into considerationwhen downloading products.

UGA-INGV velocities(Hector)