This thesis presents the development of stabilization and tracking algorithms for shipboard satellite antenna systems.
With increasing the demand for the distribution of information, the use of satellite communication having merits in breadth, efficiency and speedy of construction network, and the facility of a movement has been increasing. As the result, extensive research has been carried out on mobile terminals used in satellite communication stations .
In order to use satellite broadcasting and communication service on a navigating ship, the antenna should always point to the satellite. There are two types of stabilization control which maintains the point-angle of a satellite in spite of the changing position and movement of the ship. One is passive control which maintains a horizontality by the inertia of fly-wheel. The other is active control which compensates the movement of the ship directly by driving the actuator attached on the shaft of the antenna. Recently active control is mostly used due to the development of electronic devices and control schemes. This research is satellite tracking antenna system using active stabilizing method.
In this thesis, both a hardware system including the pedestal, pedestal control unit and antenna control unit and software for stabilization control are developed. In order to design a controller which stabilizes each control axis, a model is derived and its parameters are estimated using a genetic algorithm, and the state feedback controller is designed based on the linearized model.
Then a tracking algorithm is derived to overcome some drawbacks of the step tracking. The proposed algorithm searches for the best position using gradient-based formulae and signal intensities measured according to a search pattern. The effectiveness of both the stabilization and tracking algorithms is demonstrated through experiment using real-world data.