A location of a mobile station is estimated based on wireless communications between the mobile station and a wireless telecommunications network. Call measurement data is obtained for a call involving the mobile station and a plurality of base station antennas. The call measurement data includes round-trip delay (RTD) measurements and received signal strength (RSS) measurements. The most significant one or more base station antennas involved in the call are identified. An expected signal strength is calculated for each significant base station antenna, according to a wireless propagation model that accounts for terrain around the base station antennas. For each significant base station antenna, the corresponding expected signal strength, RTD measurement, and RSS measurement are used to calculate an adjusted RTD value. The one or more adjusted RTD values calculated for the one or more significant base station antennas are used to estimate the mobile station's location.