GPS adaptive array for use in satellite mobile communications

Satellite communications are now specially developing for land vehicles, since they provide a wide area coverage. The current state of the art makes possible both transmission to and reception from satellites. Although some systems of this kind use omnidirectional antennas, the space segment of the system is simplified if directive antennas are employed. This paper explains the design, building and operation of a new adaptive, electronically steered phased array, which can search and keep on tracking one or more satellites by pointing to one or more of them continuously. The operation is performed only in the reception mode. However, there are no problems if the system is used in transmission mode, since the method of pointing is the same. This new system is also able to compute the position of the geographic north if both the mobile vehicle and a satellite position are known. The use of position sensors or inertial navigation systems onboard the vehicle becomes unnecessary, given that the orientation of the vehicle is calculated by its own system. The array has a good communication performance even working into adverse conditions, and can be applied in urban areas, where multipath effects exhibit a particularly fast changing angle of arrival.