Abstract: A method for assisting in position determination in a wireless communication system comprises obtaining (S1) of pairs of radio frequency environment data sets for each of a plurality of common positions. A pair of radio frequency environment data sets comprises radio frequency environment data of devices of a first access technology and a second access technology at a common position. A transformation operator is created (S2) based on the pairs. The transformation operator represents a relation between radio frequency environment data sets of the first and second access technology. A method for position determination in a wireless communication system based on transformation operator and network nodes therefore is also disclosed, as well as network nodes for performing the methods.