MONITORING CHANGES IN MEAN-SEA-LEVEL TO MILLIMETERS USING GPS

The fiducial GPS technique is now well established in geodesy and geop hysics, for determining horizontal and vertical land movements. In par ticular, the technique is used in crustal dynamics and in monitoring c hanges in mean-sea-level. The main limiting factor to achieving accura cies of a few millimeters is the reference frame (or -datum), as defin ed by the adopted coordinates of the fiducial stations. This paper sum marises a series of tests which have been carried out to assess the qu ality of alternative global reference frameworks, in order to achieve the highest accuracies for tide gauge heights in the UK.