Regional densification of the IGS in europe using the EUREF permanent GPS network (EPN)

In 1995 EUREF took the initiative to coordinate the activities related to existing permanent GPS stations in Europe and created the EUREF Permanent Network (EPN) for the maintenance of the European Terrestrial Reference System (ETRS89).

Presently, the data from most of the EPN stations is available within a 24-hour delay and additionally one third of the stations provides hourly data. The performance evaluation of the EPN data flow indicates that the reliability of the hourly data flow and the development of fallback procedures in case of unreachable data centres are requiring further improvements. Half of the EPN stations belong to the IGS network and as a consequence, improvements of latency, availability and reliability within EUREF will benefit the IGS too.

Each of the twelve analysis centres process part of the EPN and obtain weekly estimated coordinates and their covariance info. The combination of these individual solutions constitutes the EPN weekly combination. The quality of this solution is in average 1.6, 1.7 and 4.9 mm for the North, East and up components, respectively.

A multi-year combination of the weekly EPN solutions was submitted to IERS for inclusion into the ITRF2000. As a first accuracy assessment this solution was compared to the ITRF2000 contribution of CODE and showed to be consistent with the internal precision of the weekly solutions.

The establishment of an EPN Coordination Group, in June 2000, allows the continuation of an efficient management of the expanding GPS tracking network and the growing array of related multi-disciplinary projects.