Abstract: A method and apparatus for location determination of a mobile station (304) in a fixed radiocommunication system having at least one base station (302) reduces the computational load on the mobile station. Satellite ephemeris information and clock correction information are received at a base station and periodically used to calculate satellite position data. The satellite position data are conveyed to the mobile station. At other times, the satellite ephemeris data is used to calculate curve fit data at the base station. The curve fit data is transmitted to the mobile station, reducing the amount of data conveyed over the communication link and the computation load on the mobile station.

Abstract: A method and apparatus accurately synchronizes a communications equipment (101) to a precise 1 PPS signal (229) when the remote GPS equipment (112) and the communications equipment (101) are separated by a cable (110) of unknown length. Accordingly, integrity and precision of the 1 PPS timing signal is maintained when synchronizing the communications system.

Abstract: An apparatus for improving the acquisition time of GPS signals includes a GPS receiver (21) and a real-time clock circuit (30). The GPS receiver receives GPS signals including a precise time reference signal for providing a position based upon the location of the GPS receiver. The GPS receiver also includes an internal time base (11) derived from the precise time reference signal. The real-time clock circuit is coupled to the GPS receiver for receiving a first time reference signal from the GPS receiver when the precise time reference signal of the GPS signal is available and for providing a second time reference signal to the GPS receiver when the precise time reference signal of the GPS signal is not available thereby allowing a fast acquisition time of GPS signals when the GPS signals are temporarily interrupted or not yet available.

Abstract: In a telecommunication system (15) with at least one gateway (1), at least one subscriber unit (2), a system controller (3), at least one communication satellite (4) and global positioning satellites (5), communication satellite (4) provides positioning information to subscriber units (2). System controller (3) uses links (13,14) with communication satellites (4) to control links (10,11) and links (8,9). Subscriber unit (2) receives on link (6) positioning information which is used by subscriber unit (2) to determine which global positioning satellites (5) are overhead. Knowing which global positioning satellites (5) are overhead allows subscriber unit (2) to more quickly acquire and track the global positioning satellites (5) required to accurately geo-locate itself. Subscriber unit (2) computes accurate location data and can transmit this data to gateway (1).

Abstract: A periodic pulse generator has a programmable counter (15) and processor (10) coupled to a GPS receiver for generating a periodic clock signal. The processor (10) transmits a control word to a digital to analog converter (20) which steers a voltage controlled crystal oscillator (25), processor 10 also controls the programmable counter (15) to produce a stable output pulse, if the voltage controlled crystal osciallator (25) output is an integer frequency.