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Integrated Magnetometer-Horizon Sensor Low-Earth-Orbit Determination

Farahani far, Mohammad | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43728 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Asadian, Nima
  7. Abstract:
  8. In this thesis, the orbit determination of Low Earth Orbits (LEO) using the integrated magnetometer and horizon sensor data has been investigated. Orbit determination is an essential part of a space mission. Not only the modeling, guidance, navigation and control errors may results in error in injecting the satellite into its nominal orbit, the environmental disturbances deviate the satellite from its predicted orbit and from an operational perspective most satellites need continuous orbit determination. Traditionally, ground based orbit determination is used which are non-autonomous and expensive and just can be used for specific times which the satellite can be observed from the ground stations. Thus, they are not preferred for small full-autonomous satellites. Recently, utilizing attitude sensors for orbit determination has dragged the attention of the researchers. Magnetometer is a part of attitude control subsystem of most small satellites. Recent developments in Earth/Horizon sensors have been initiated the increase usage of them in small satellite to achieve more accuracy with small budget of mass and power. Therefore, the integrated magnetometer and horizon sensors are available in modern small satellites and by using their data for orbit determination, there is no need for further sensors and mechanism. In this study, after using only the magnetometer data for orbit determination, the horizon sensor data has been integrated into the filter and better accuracies are achieved. The major accomplishment of this thesis is integrating the magnetometer and horizon sensors and using the Gauss variation of parameters formulation for the dynamic model and Unscented Kalman Filter (UKF) for orbital elements estimation. The sensors are assumed to be subjected to bias and scale factor errors and these errors are also estimated. The substantial advantage of using Gauss VOP over the Cowell formulation has been shown by the results.
  9. Keywords:
  10. Magnetometer ; Unscented Kalman Filter ; Horizon Sensor ; Low Earth Orbit (LEO)Satellite

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