An Real-Time Kinematic (RTK) and/or Differential GNSS (DGNSS) system is disclosed in which correction data from a plurality of reference stations is provided to the mobile device. A selection of reference stations (from which correction data is provided to the mobile device) can be made based on factors such as the approximate location of the mobile device, geometry of the reference stations, and/or other factors. The mobile device can combine the correction data from the plurality of reference stations in different ways to determine an accurate position fix for the mobile device, without interpolating correction data from the plurality of reference stations.