A method of calibrating an adaptive antenna array that applies beamsteering (1) of a satellite navigation system comprises receiving signals from a plurality of satellites at a plurality of receivers (2) within the system. The satellite direction relative to the antenna array orientation for each satellite signal is determined (5); and the received signals are despread (8) to recover satellite signals. Gain and phase information is calculated from the despread code for a given satellite in a given direction; and the calculated gain and phase information are stored in a manifold store (4) at a predetermined address related to the direction of arrival of the satellite signal.