Minutes of the EUREF AC Workshop (Warsaw, May 31 - June 01, 2001)
by Carine Bruyninx, Royal Observatory of Belgium
Session 1: AC Reports
Session 2: EPN Special Projects
Session 3: Processing Strategies
The presentations can be viewed by clicking on the title of the presentation.
Summary of Discussions/Action Items
DATA PROCESSING STRATEGY
(T) : Guideline for AC's contributing to Trop. Special Project !
MANAGEMENT OF COORDINATE OUTLIERS AT AC LEVEL
Each EPN station is minimally processed by 3 AC's. These 3 different solutions allow to detect and remove outliers at the combination level. In practive, the solution for a specific station from an AC is eliminated if it differs from more than 5 mm horizontal and 10 mm vertical from the combined solution.
The EPN AC's base their weekly submission to EUREF on daily coordinate estimates. These coordinates can show outliers, (e. g. due to degraded data quality) or a jump (e.g. due to a change in the antenna configuration). Both types of outliers will degrade the quality of the combined solution. In addition, if some of the AC's remove or correct some of the outliers and others do not, then big diferences between the individual solutions can show at at the combination level. If the Analysis Coordinator does not have any information available about the editing of the daily solutions, then he will not have the information to make the best decision about the elimination of a specific solution.
The handling of deviations of the daily solution at each AC should be unified. Therefore G. STANGL and H. HABRICH will develop guidelines that will allow the AC's to make similar decisions about the edition of the daily solutions (e.g. when a configuration change has occured at the station). In addition, a machine readable format will be developed to provide this edition information, through the weekly summary file, to the Analysis Coordinator.
CONTRIBUTION TO THE TROPOSPHERE SPECIAL PROJECT
The goal of the EPN Special Project on the Troposphere is to generate a EPN troposphere product. The chairman of this Project (G. Weber) has encouraged all AC's to contribute to this product. The present engagement would consist in contributing to a post-processed ZTD product. This will not require any substantial additional computations from the AC as the ones presently done for their routine submission to the EUREF combined SNX solution.
Guidelines for the generation of the TROP_SNX files (standard format for the exchange of ZTD) are :
This method will guarantee for each AC the highest consistency between the weekly SNX submission and the daily TRP submissions. The daily TROP_SNX files have to be submitted to ftp://igs.ifag.de/EUREF/eurefin.
The Trop. Coordinator will set up a seperate mailing list that could be used for all exchange of information related to this project.
CONTRIBUTION TO TIME SERIES SPECIAL PROJECT
One of the goals of the EPN Special Project "MONITORING OF THE EUREF PERMANENT NETWORK TO PRODUCE COORDINATE TIME SERIES SUITABLE FOR GEOKINEMATICS" is to determine a unified velocitity field over Europe and its surrounding zones. Since the network of EPN stations is not dense enough for this purpose, this project aims at expanding the present EPN network with additional stations.
The chairman of the "Time Series" Special Project (A. Kenyeres) has asked the AC's to provide him with the following information :
RAPID MONITORING OF THE EPN STATIONS
The feedback of the EUREF combined solution is for some EPN stations their primary means to asses the quality of their observations. The delay of this combined solutions (often more than one month), make this monitoring far from being optimal.
Since a lot of the AC are producing a "rapid solution" based on IGS rapid or predicted orbits, the Network Coordinator (C. Bruyninx) has encouraged these AC's to distribute this info to the other AC's using the AC mailing list : email@example.com.