National Report of Sweden to the NKG General ... - Lantmäteriet

3- Provide DGPS 13 /DGNSS 14corrections and RTK data fordistribution to real-time users.- Act as the continuously monitoredfoundation of the national referenceframe SWEREF 99.- Provide data for geophysicalresearch.- Monitor the integrity of the GNSSsystems.During 2006, a sub-group of the NKGproject Nordic Positioning Servicedeveloped a classification system ofpermanent GNSS stations (Engfeldt etal., 2006). The system includes fourdifferent classes; A, B, C and D, whereclass A is the class with the highestdemands and the system was adoptedby Lantmäteriet in 2007.Today (September 2010) SWEPOSconsists of totally 195 stations, 37 classA stations and 158 class B ones, seeFigures 1.2 and 1.3.Figure 1.3: Söderboda is a SWEPOSstation with a roof-mounted GNSS antennamainly established for network RTKpurposes belonging to class B.This means that the total number ofSWEPOS stations has increased with 90stations since the last NKG GeneralAssembly, see Figures 1.4 and 1.5.The class A stations are built onbedrock and have redundantequipment for GNSS observations,communications, power supply, etc.They have also been connected byprecise levelling to the national preciselevelling network.Class B stations are mainly establishedon top of buildings for network RTKpurposes. They have the sameinstrumentation as class A stations(dual-frequency GPS/GLONASSreceivers with antennas of DorneMargolin design), but with somewhatless redundancy.Figure 1.2: Överkalix is one of theSWEPOS stations belonging to class A.13DGPS = Differential GPS14DGNSS = Differential GNSS