Disclosed is a method performed by a position calculation node (160) in a wireless communication network (100). The node (160) is arranged for improving accuracy when determining positions in the wireless communication network. The method comprises obtaining a signal transport time value for each of a plurality of different geographical UE positions (UE1, UE2, UE3), wherein the respective signal transport time value relates to the time it takes for a radio signal to travel between a first base station and one of the plurality of UE positions. The method further comprises obtaining a geographical position value for each of the plurality of different geographical UE positions, the position values being independent of the signal transport time values, and determining an actual geographical position for the first base station, based on the obtained signal transport time values, the obtained position values and a predefined geographical position for the first base station.