Abstract
Recently, small Earth observation satellites have been utilized, and an agile large angle satellite attitude maneuver has been required. Meanwhile, small Earth observation satellites acquire high-resolution data, which results in an increase in the time required for data communication. However, the directly data communication is limited because of the short visibility to ground stations. The situation can be improved by a data relay via GEO-stationary satellites. Owing to these reason, it has become important to ensure that small Earth observation satellites are capable of being maneuvered rapidly and to extend the communication time by using a data relay system. In conventional operation, the antenna motion is carried out after satellite attitude maneuver. But this method has a time delay between the completion of the attitude maneuver and the start of data communication. The purpose of this study is to extend the time of Earth observation and data communication. To achieve the purpose, we propose a simultaneous control method of satellite maneuver and antenna motion. Proposed method solves minimum-time optimization problem restricted by state equation. Firstly, we divide the control input to transfer a minimum-time optimization problem to a nonlinear programming problem. Secondly, we solve the nonlinear programming problem by the sequential quadratic programming. To verify the effectiveness of the proposed method, numerical simulations are carried out under condition of rest-to-rest attitude maneuver mission in this paper. And we confirm that the proposed method could reduce the total settling time of the satellite and antenna.
