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Design of a novel satellite attitude determination algorithm Mehrzad Nasirean : PHD student-IRAN-kntu university Hossein. Bolandi : Associated Professor of faculty of Electrical Engineering of IUST-IRAN-iust university
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Design of a novel satellite attitude determination algorithm Mehrzad Nasirean : PHD student-IRAN-kntu university Hossein. Bolandi : Associated Professor of faculty of Electrical Engineering of IUST-IRAN-iust university Ali. Khaki. Sedigh: Professor of faculty of Electrical Engineering of KNTU-IRAN-kntu university Ahmad. Reza. Khogar: Assistant Professor of faculty of Mechanical Engineering of MUT. IRAN-kntu university
TITLE: 1- Modeling 2-Satellite attitude control law 3-Satellite attitude determination 4-Simulation and results
1-Modeling 1.1. Satellite attitude kinematics equation 1.2. Satellite attitude dynamic equation (constant)
1.2. Satellite attitude dynamic equation (variable) 1.3. Earth gradient torques
4. Satellite attitude determination 4.1. Earth magnetic intensity vector
Earth location in sun inertial coordinate system Satellite location in Earth inertial coordinate system Obtain satellite location in sun inertial coordinate system With respect to 23.44 ° earth rotation axis. + Obtain sun vector in sun inertial system after making unit vector and 180° phase change Obtain sun vector in earth inertial coordinate system ُsun vector in body coordinate system 4.2. Sun tracker
4.3. Attitude determination flowchart Tx,Ty,Ty + Actuator Controller Dynamic 1 Noise A Sun and magnetic vector in body coordinate Obtain angles of each two vectors in respect with three axes of body I Sun sensor model Accept unit vector + Sensor simulator Characteristic of orbit and time B Obtain angles between sun vectors and body vectors relation to three body axes verses current of sensors Sun and magnetic vector in body coordinate Obtain orthogonal coordinate in orbit coordinate Obtain orbit matrix Obtain sun vector and magnetic vector from angles in body coordinate Obtain transformation matrix from orbit to body coordinates Obtain Euler’s angle (Ф,,Ө) , noisy x Obtain orthogonal coordinate in body coordinate 1 Obtain body matrix Mb
4.Simulation and result: • Characterestics designal considerations are as follows: • Size,mass610kg • Altitude in Circle orbit is700km and inclination angle is • Precision of roll and pitch axes is and yaw axes is • The required inertia momentum after the expanded boom are • The required inertia momentum before expanded boom are
4.1.Attitude and velocity angles in the transition mode Wx Ө Wy Wz
Wx Φ Wy θ Ψ Wz 4.2. Attitude and velocity angles in the mono mode