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.
The DORIS network of tracking beacons was established by IGN in 1986 and has been run and maintained by them since then. Geodetic files describe the stations of the DORIS network. They are avilable on the web site of IDS (International DORIS Service) on a page that also has a dynamic map showing the geographical distribution of the network (click on the link).