Observers for spacecraft attitude estimation / Mohamed Mohamed Aly Mohamed ; Supervised Ahmed Gamal Bahgat , Hossam Eldin Ahmed Abd El Fatah , Mohamed Abd El Kawy

Thesis (M.Sc.) - Cairo University - Faculty Of Engineering - Department Of Electrical Power and Machines

moderate - accuracy attitude determination systems for Earth - pointing spacecraft typically use Gyroscopes , Earth and Sun sensors for attitude sensingThe Earth sensor can provide continuous roll and pitch data , while the Sun sensor can provide roll and yaw dataHowever , due to spacecraft eclipse periods and limited field of views , these data are available for only part of each orbitMoreover , from economical perspective , if a suitable observer is developed , it can replace the Sun sensor in the spacecraft eclipse periods therefore , a substantial cost reduction will be achievedTo address this issue , the thesis is concerned with an investigation and comparison of observers that can be used to estimate the yaw angle informationThe spacecraft ADCS exhibits several modes ; we are concerned with the pre - stabilization mode , where the variations in the attitude angles are relatively smallThus our concern is to consider observers that are locally defined and are operating in the presence of a stabilizing controller which insures the small angle deviationsDue to its simplicity and acceptable performance , linear controllers are used in conjunction with the observers

Issued also as CD