Towards a dynamic reference frame in Iceland

There is a growing need for geodetic reference frames that on a national level support the increasing use of global positioning services. Today, the vast majority of countries have their own national reference frame. In Europe this frame is normally aligned to ETRS89. This system is co-moving with the Eurasian tectonic plate.

Global Navigation Satellite Systems (GNSS) and global positioning services are normally aligned to the Earth as a whole through a global reference frame like ITRF2014. Consequently, global positioning services does not give direct access to the national reference frame without a time-dependent transformation.

A solution is to align the national reference frame directly to a global reference frame. In such a frame, the coordinates of a point fixed to the ground will change with time, - a fact leading to the expression dynamic reference frame (DRF).To be prepared for future challenges, the Nordic Geodetic Commission (NKG) initiated a pilot-project on DRF in Iceland.

Iceland has a very active and complex geodynamic situation. It is located at the boundary of two tectonic plates and affected by seismic and volcanic activity, recent ice loading changes as well as glacial isostatic adjustment (GIA). Due to this, the traditional concept of a static geodetic reference frame is difficult to maintain at the uncertainty level required by modern applications.

Iceland was therefore a natural place to investigate the concept of DRF. This paper focuses on the outcome and conclusions of the DRF project in Iceland. We give ten preconditions for a DRF. Living on an ever-changing Earth, we see that many of these precondition shave to be in place regardless of type of reference frame.

Through the work in the Nordic countries and NKG, the Nordic area will be well prepared for the future challenges. However, some legal issues for instance, can be challenging. A two-frame solution combining static- and dynamic- reference frames seems like the best alternative in the foreseeable future.