چكيده به لاتين
Due to the complexity and the need for high precision in the implementation of new space missions (such as inspection operations, formation flying and refuling), the required processes and decisions must make on-board by the reference satellite. In these operations, the behavior of relative motion of satellites in different situations is become Importance.Most of the priviouse models produce large errors in highly elliptical orbits and far relative distances. The main reason is that these models only consider the perturbation effect on the follower satellite.The aim of this study is to provide a high-fedility model for relative motion of satellite that has no limitations (assumptions such as: short time of flight, small magnitude of relative distance compared to position vector of reference satellite, regardless of perturbation effects on reference orbit, low eccentricity, not taking into account all zonal harmonic coefficients and disturbation of inclined third-body) to priviouse works.
The relative hovering of satellites in highly elliptic orbits (HEO), as one of the most crucial space operations, is modeled and analyzed in this paper. The proposed modeling is based on the new perturbed relative dynamics equations, uses the time-varied parameters depending on the motion of the target satellite. This proposed model considered the air drag, oblateness of Earth (including all zonal harmonics coefficients) and the Lunar perturbation as a third-body effect on both follower and target orbits. The hovering thrust has been obtained without any simplifications ensuring the accuracy of long-term analyses. To validate the presented model, another model has been built as an ECI based Relative Motion (ERM) model. Then, according to effective parameters on hovering mission design around HEOs such as the eccentricity and inclination of the target obit, the fuel consumption, optimal positioning of the follower, maximum required thrust, and the appropriate time to perform the operation, several examples are provided. Furthermore, the hybrid Invasive Weed Optimization/Particle Swarm Optimization algorithm has been used to find the location and the minimum and maximum amounts of thrust force.
Also, the obliquity effect of the main-body on the motion of solar system planets orbiter in prolonged space missions has been investigated in the presence of the Sun gravity. It is shown that the neglected short-time oscillations in priviouse works can accumulate and propel to remarkable errors in the prolonged evolution. It is shown that the main-body’s obliquity has some significant effects on orbit charactrastics and short-time oscillations must be considered in accurate prolonged evaluation. The importance of the main-body’s obliquity is proved by several examples related to the Earth-Moon system in relative motion, Lunar satellite formation keeping and the behavior of orbiter in Mars-Sun, Venuse-Sun and Earth-Sun systems.
Also, a High-degree cubature quadrature Particle filter is introduced by combinig of Particle filter and High-degree cubature quadrature Kalman filter, due to the importance of relative navigation in formatin flying missions. Generally, the progressive estimation algorithm can effectively compensate for the defects due to the accuracy of the sensors used. The proposed filter produces more reliable results than the variation frequency of observations and far distance of satellites.
