Orbital Dynamics Modeling, Based on Separating Orbital Elements to Control Low-Altitude Satellites

In this paper a new viewpoint to orbital dynamics simulation is introduced. The novel proposed method is based on the manner by which the orbital elements change in the presence of disturbances. Satellite orbit dynamics is often expressed by Cowll and Enke methods. These methods include solving a set of second-order non-linear differential equations, with all disturbance force deviation effects in the Cartesian space. These forms of dynamics require converting the Cartesian components to orbital elements so that these element changes can be obtained. Here,Gauss’s method has been used to convert the dynamics model into six first-order non-linear equations whereby orbital elements can be directly extracted from these equations. Then, “Corrected Disturbance Viewpoint” is defined for low-altitude orbits. In this viewpoint, J2 oscillatory effect is assumed as a part of orbit dynamics. Other effects such as higher order terms of oblateness (J3-J6), drag aerodynamic force, third-body, radiation pressure and J2 longterm effect have been considered as disturbance factors in the dynamics. The main advantages of this proposedviewpoint in comparison with the previously suggested methods are: a) separation capability between oscillatory and long-term effects in disturbances, b) more concise and accurate calculations, c) reducing fuel consumption in the orbit correction process, and d) simplicity plus feasibility of control methods. The performed simulation results support the aforementioned advantages.