Percorrer por autor "Cardoso, Clara Braga"
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- Robust Kalman Filtering in the Framework of Space CommunicationsPublication . Cardoso, Clara Braga; Bousson, KouamanaA Low-Earth orbit (LEO) is the trajectory of a space vehicle relative to the Earth, with an altitude equal or below 1500 km. A real LEO trajectory is far from an ideal orbit (Keplerian Orbit), because in addition to the gravitational forces from both bodies, the orbit is influenced by perturbation like the oblateness of the Earth and the atmospheric drag. These perturbations alter the planned trajectory, making it imperative to estimate and predict a satellite trajectory to know its possible deviations and when to correct it. Currently, the Kalman filter is a reliable option for a trajectory estimation. Although it is an algorithm simple to implement, it is necessary to know all the parameters of the system. So, the efficiency of the discrete Kalman filter depends on practically the full knowledge of the systems specifications: which, is pratically impossible in a aerospace context. This entails that it bust be implemented a Kalman filter dynamic enough to endure the simplication of the unknown parameters of the system without damage and increase the discrepancy between the real measured values and the estimated results from the filter. This dissertation focus on the Kalman filter application to a communication satellite and how the uncertainties associated to a system with noisy measurements are handled. And, although tht classical form of the filter results in a estimation that very well decreases all the noise, it was also implemented a robust application to improve tha Kalman filter’s performance.