Statistical map-based algorithms for determining the attitude and orbit of a satellite

Abstract

In this dissertation, we investigate statistical map-based algorithms for determining the attitude and orbit of a satellite. The attitude determination is to estimate the orientation of a coordinate system in the satellite with respect to some reference coordinate system. If measurements of the number of stars inside the field of view of a star sensor are gathered along rotation of the satellite, the estimate of the orientation can be obtained by adopting a recursive nonlinear estimation method. We propose a simple attitude determination method based on the bootstrap filtering approach using a star sensor. The proposed method estimates the Euler angles and can omit the point-pattern matching techniques in the whole system. By processing a sequence of measurements in the rotating body fixed frame, the estimates of the Euler angles can be obtained by comparing the measurements with the reference discrete star-density maps whose grid values are the statistical number of stars inside the FOV of a star sensor. In this estimation problem, the system and the measurement models are highly nonlinear functions of the state. Moreover, measurements are drawn from a finite nonnegative integer set rather than from real numbers, and the measurement noises are modeled as non-Gaussian probability density functions. In this case, the well-known extended Kalman filter cannot be used. We also propose another method which can reduce the computational load by using dual star sensor. The orbit determination of a satellite is to estimate the orbital elements as a function of time. We propose a new autonomous orbit determination method for a LEO-satellite from measurements of geomagnetic field intensity. The proposed method is based on the generalized simulated annealing technique which is capable of escaping from local minima and converging to the global minimum. It uses the magnetometer measurement only, and does not require additional information, such as the attitude of the satel...