The invention relates to a method for determining transmission times of signals transmitted by at least one radio transmitter BTS. In order to enhance the accuracy and reliability of estimates of transmission times or of changes of the transmission time of signals transmitted by radio transmitters BTS, it is proposed that a difference in the time level of estimates of the transmission times based on the measurement results of two different radio receivers LMU A,B is taken into account in a filtering of the estimates for obtaining an accurate value for the transmission times. It is further proposed that the changes of the transmission times estimated at different receivers LMU A,B is averaged for obtaining an accurate information about the changes. The invention equally relates to a corresponding radio communications system and to a processing unit for such a system.