Accuracy improvement of ship mounted tracking antenna for satellite communications

Recently, data traffic for satellite communications is increasing rapidly, due to various new purposes besides the conventional voice phone and facsimile. For the reason, it is necessary to realize high frequency communications, which is to be assured by high accuracy of tracking control of an antenna. To meet the needs, this paper aims at the accuracy improvement of conventional ship mounted tracking antennas by introducing H-infinity control. In this paper, the basic characteristics of tracking antenna are investigated by experiments and the model of the antenna for controller design is established. Based on the model, an H-infinity controller is designed and implemented to the antenna. Experimental results show that the tracking accuracy can be improved to /spl plusmn/0.3 [deg], which is five times higher than that by the conventional controller.