1. A method, for determining a location of a mobile communication device in a network service area when a quality of locating signals is not stable, comprising: obtaining, from a locating unit, periodically, instantaneous location coordinates corresponding to the mobile communication device; calculating, by a processor in the mobile communication device, average location coordinates corresponding to a sliding time window over a plurality of time periods; calculating, by the processor, for the sliding time window over the time periods, error values indicating deviations between the instantaneous location coordinates and the average location coordinates; determining, by the processor, for the sliding time window over the time periods, peak error values; and determining, by the processor, for the sliding time window over the time periods, the location of the mobile communication device based at least in part on the instantaneous location coordinates if the peak error values are within pre-defined threshold.