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A mobile satellite communication system is installed on a moving carrier for satellite communication. The tracking and stabilizing problem of the mobile satellite communication system is studied in this paper. The tri-axis nonlinear model of the mobile satellite communication system is chosen as the control object, because it can describe the kinematics and dynamics features of the system more accurately than the single-axis model. Based on the actuator dynamic features, a nonlinear robust controller with actuator dynamic compensation is designed. The designed controller can eliminate the disturbances when the carrier is moving and track the target satellite accurately. Because the problem of the actuator dynamics is further considered, the controller is more suitable for the practical application. At last, three sets of comparative simulation results are used to verify the tracking and stabilizing effectiveness of the designed controller under different disturbances. [ABSTRACT FROM AUTHOR]

Double Lunar-Swingby (DLS) trajeclories have received much attention due to its wide applications in the trajectory design of Multi-Mission and Multi-Purpose'. First, the DLS orbits are divided into two classes named Plane type and Backflip type according to their space configuration and characteristics. Then, the basic theory of swingby is shown based on two dynamics models of Zero-Sphere-of-Influence and CR3BP. Furthermore, both dynamics and modeling of Plane type DLS trajectory are discussed in two categories of application, and the principle and solution methods of Backflip type orbit is also summarized in detail. This study and survey about DLS trajectories could provide a new insight and reference for the interplanetary' mission of China. [ABSTRACT FROM AUTHOR]