As with GPS, the DORIS system can provide information on the exact localisation of a tide gauge and its stability in a geocentric land bench mark. The map below shows the co-locations of the DORIS tracking beacons with tide gauges. You will find details of this co-location here: summary table (click on the link).
Co-location is understood here to refer to instruments observing continuously nearby (less than 10km). The aim is to have as accurate an idea as possible on the state of the tide gauge and if the possibility exists to link the tide gauge reference, and to monitor its vertical movement in a geocentric bench mark.