Tracking system with beam switching antenna

摘要

In a tracking system for a stationary satellite, a phased array is used for an antenna mounted on an automobile. The phased array antenna has a sharp beam which is switched between two different directions in azimuth. The antenna beam is switched between the two directions periodically by control of phase constants in a feeding circuit of the antenna and comparison is made in strength between signals received before and after the beam switching to obtain an error signal as an azimuth error signal. Then, the antenna is mechanically moved in azimuth according to the azimuth error signal until the azimuth error signal becomes zero. In a case the antenna beam is also switched between two directions in elevation, the antenna beam is switched in elevation during an interval between successive two times of the beam switching operation in azimuth and detects a difference in strength of signals received before and after the switching in elevation to thereby produce the difference as an elevation error signal. The antenna is mechanically moved in elevation according to the elevation error signal until the elevation error signal becomes zero.