Study On The Autonomous Orbit Determination And Control System Of Near Earth Satellite

Orbit determination and control is an old topic and mature field in celestial mechanics. Meanwhile, It's the essential part of the satellite navigation. For China, the idea of autonomous satellite navigation is an attractive and challenged subject.The main objects of this dissertation are to develop state estimation theories and establish a united frame for the satellite autonomous navigation. Furthermore, the problem of minirnum time orbit transfer in strong central gravitational field is also studied. The major ideas in the dissertation are summarized as follows:1.Based on the introduction of a new variable, completely general closed-form solutions are given for both the rectangular coordinates of the two-body problem and their partial derivatives with respect to their initial values. The complete generality and simplicity of the solutions make them valuable for many practical applications of the two-body problem.2.Based on the algorithm of Extended Kalman Filter(EKF), the errors resulted from linearization are analyzed qualitatively and some useful conclusions are abtained. Then computation capacity of EKF is studied. The key to reduce the algorithm computation capacity is to simplify the computation of filter's gain matrix.3.hi order to avoid divergence of EKF, we proposed a modified EKF algorithm and prove two basic theorems. The new algorithm improves the corrective capability to new information. Moreover, the computation capacity is not more complicated than that of EKF.4. Adaptive filtering algorithm of discrete linear periodic system is studied. Then we extend the algorithm to the nonlinear system with a periodical nominal trajectory, and a navigation filter is developed with the algorithm. Finally, from requirements in practical application of nonlinear system, we modify the parameter identification algorithm of linear periodic system to keep the parameter tracking ability.5. An approach of autonomous navigation for low earth orbit (LEO) satellites using magnitudes of the geomagnetic field is presented. A novel set of the state vector make the derivatives of the model with respect to the state vector easy to solve. At last, simulation for a sun-synchronous orbit satellite is done, and the effectiveness andpracticality of the autonomous navigation method using the magnitudes of geomagnetic field vector have been shown. The navigation system designed with the method possesses the advantages of the inexpensive hardware and the simple algorithm, and can satisfy the moderate accuracy requirement of LEO satellites or be a redundant system.6. An approach of autonomous navigation for satellites is described in this paper by using refraction measurements of starlight passing through the upper atmosphere. An Extended Kalman Filter (EKP) has been designed to estimate the satellites' position and velocity. Simulation for a sun-synchronous orbit satellite is executed. The results show that the satellite's position accuracy is about 0.038km. Moreover, results show that the measurement error of starlight refraction angle and the uncertainty of the atmospheric refraction model are two principal factors responsible for deteriorating the navigation accuracy.7. Minimum time constant thrust orbit transfer in strong central gravitation field is studied. For the purpose of optimal thrust direction determination, Pontryagin's Maximum principle is combined with the motion equations of spacecraft. Next, the problem of optimal trajectory construction is divided into two subproblems. The first one is named the 'inner', hi this case, slow variables have small enough changes that it is possible to linearize the inner problem and obtain its analytic solution, hi turn, the second subproblem is named the 'outer'. This one is to determine the dynamics of slow variables, considered as the functions of the number of the revolution.The major contributions of this dissertation are:1. An approach of autonomous navigation for low earth orbit (LEO) satellites using magnitudes of the geomagne...