Abstract: The synchronization system uses a TDMA or AMPS air interface to provide timing synchronization between previously unsynchronized base stations. The synchronization of base stations is critical between when determining the geographical position of a mobile because the geographical position is determined using a time difference of arrival method. In order to synchronize a remote base station with a serving base station, the remote base station receives a signal from the serving base station and measuring the receiving time of the signal at the remote base station in relation to the clock of the remote base station. The synchronization system determines the transmission time of the signal based on the reception time of the signal and the distance between the base stations, in relation to the clock signal of the second station, and synchronizes the clock of the remote base station to the clock of the serving base station based on the offset in the clock cycles at the time the signal was transmitted.

Abstract: A hybrid amplitude/phase comparison direction finding system for aircraft, employing a unique calibration system to compensate for tolerance variations in the antennas. The calibration system utilizes a programmable read only memory (PROM) for each antenna pair, wherein calibration data from pre-measured antenna patterns of the associated antennas are stored. The calibration data preferably includes measured relative amplitude (electromagnetic field strength) and phase data, as a function of frequency and angle from a common reference plane, for the associated antenna pair. This calibration data is stored in a PROM which is preferably disposed within an assembly which includes the antenna pair. A system processor can then retrieve the calibration data during system operation, whereupon angle of arrival measurements can be performed with improved accuracy.