The attitude determination and control system makes use of a magnetometer as the primary attitude sensor and SCDM as secondary attitude sensor. An on board GPS senses the position and velocity vector of the satellite. The actuators are three in-house designed magnetorquer coils which interact with the earth’s magnetic field to produce the required torque for correction.
The B-dot control law is applied to reduce the angular rates during detumbling. After the satellite has detumbled, the Sun model computes sun vectors as a redundant attitude determination system. The measurement model comprising of sensory inputs and computed attitudes is fed into the Kalman Estimator for estimation and prediction of the response of the controller. According to error in the magnetic field value, or sun vector error, proportional amount of current is supplied to the Magnetorquers for rotation of satellite in the required direction as attitude control as shown in fig. below.