The invention relates to a wireless mobile communication system (400), such as a mobile telephone network. Network configuration data may contain inaccuracies, such as an error in the location of a base station (432, 434). These inaccuracies may lead to errors in estimating the location of a mobile communication unit (410). The invention creates probability density functions for the location of a mobile communication unit, based on communications with the mobile communication network (430). A confidence score may be calculated for each probability density function. A combined function can then be derived from the individual confidence scores. Maximization of the combined function may then lead to a corrected value for a network parameter of the network configuration data. Corrected network configuration data leads to more accurate measurements of the location of mobile communication units. In addition, upgrades to the antennae and base stations can be planned more effectively.