Control Measurements Between the Geodetic Observation Sites at Metsahovi

The Metsahovi research station of the Finnish Geodetic Institute hosts instruments of all basic space geodetic techniques, including geodetic VLBI, SLR, GNSS and DORIS. The local control network is an essential part of the station. Tie measurements between the network benchmark bolts and pillars and instrument reference points are needed to control the stability of the installations, and to tie them with each others and to the global reference frame. We use precision tacheometry to determine relative positions, and GPS for measurements for orientation of the local control network. Precise levelling data is available, too. One millimetre 3-D accuracy is expected. We describe measurement methods and give results obtained so far. Further measurements are required to obtain the final ties for the VLBI reference point and the new SLR instrumentation, which currently is under construction. Results are compared with the control measurements in 1997.