The GPS reference receiver at Aalborg University

A profesional choke ring GPS antennaDGC continuously operates a reference station at Aalborg University. This station provides Global Positioning System (GPS) carrier phase and code range measurements. Surveyors, engineers, scientists, and students can apply these data to position points at which user data have been collected.

The tracking data is provided as Zip compressed RINEX files, and the daily compressed RINEX file contains an observation file and a navigation message file. Data rate is 30 seconds, and all files contain observations for a 24 hour period, from 00:00:00 till 23:59:30 GPS time. The navigation message files contain the broadcast messages collected by the tracking station between 00:00 and 23:59 GPS time.

Observation files can be downloaded here:

Observation and navigation files since year 2000 until today

The file naming follows the convention "NNNNddds.yy" where:


is the site name; AAUC for this one


refers to the day of the year,
eg. 056 corresponds to Feb 25th


is the session number, eg. 0


is the two last digits of the year

The Aalborg University reference station site coordinates are:









Ellipsoid height




The cartesian coordinates are referenced with respect to the International Terrestrial Reference Frame 1996 (ITRF96), and the geodetic coordinates are referenced with respect to the World Geodetic System 1984 (WGS84).

An example where the station data is used

The station is recording GPS measurements every 30 seconds every day of the year. It is a lot of measurements, so who is using it?

Such type of data is used for several different purposes, but most of them are various scientific applications. One example is monitoring how different parts of Earth (for example - continents) drift with relation to each other. Often the actual interaction of the tectonic plates is monitored using GPS measurements at various locations.

Today's computer power allows to process data from 1500 stations for a region like Europe. The measurement span can be years or decades depending on the actual research goals.

Here is one example of results for our station from this kind of study. The presented here results show that our station is uplifting about 1mm per year.

These results were kindly provided to us by Goran Buble from Department of Geosciences, University of Arizona, 1040 E 4th street, Tucson, AZ 85721 USA.

Danish GPS Center, Fredrik Bajers Vej 7C, DK-9220 Aalborg Ø, Denmark, Tel +45 9940 8362, E-mail: gpscenter(at)