Attitude Determination System (ADS) is a process to determine the attitude of a satellite by using on board sensors and attitude estimation algorithms to determine the orientation of the satellite which is relative to inertial reference frame such as Earth reference frame. The ADS is consists of an attitude sensor which provides the attitude and orbital position of the satellite to the Attitude...

When a robot arm(s) conducts some tasks on a satellite, the satellite attitude stability is necessary against the robot arm's motion to maintain the communication link and to generate electrical power from the solar panel(s). However the reaction from the robot arm is much stronger than the natural environmental disturbance torque that the traditional satellite attitude control system cares. Na...

This paper discusses the influence of aerodynamic drag torque on the dynamics of a satellite in a very low altitude orbit. The larger atmospheric density in low altitude earth orbits results in significant aerodynamic drag torques acting on the satellite. With a conventional satellite design this may result in instability. This paper shows how the instability can be avoided, and how the aerodyn...

Neural networks are non-linear functional approximators, and natural candidates to be used in nonlinear systems control. Satellite nominal attitude control dynamics is an example of non-linear system where conventional control has been applied sucessfully since the early space age. However, conventional control like the PD (proportional and derivative of the error) can only guarantee robustness...

These days, nano (1 kg – 10 kg ) and micro (10 kg – 100 kg) – satellites, which are smaller than conventional large satellite, provide space access to broader range of satellite developers and attract interests as an application of the space developments because of shorter development period at smaller cost. Several new nanoand micro-satellite missions are proposed with sophisticated objectives...

Attitude determination, along with attitude control, is critical to functioning of every space mission. Here, we investigate the application of a steady-state Kalman Filter for attitude determination using attitude sensors (sun sensor and horizon sensors) and rate integrating gyros. The three-axis steady-state Kalman Filter formulation, adopted from literature, offers obvious computational adva...

In attitude determination using GPS, the accuracy of results is influenced directly by the satellite selection of the differenced observations. Based on the information of satellites, such as elevation, azimuth and signal to noise ratio, we apply a weighted selection method to obtain the satellite combination used in attitude determination. This method also considered the quality of satellite s...

The Ørsted satellite mission imposes comparatively high requirements on autonomy of the attitude control system. Cost requirements, on the other hand, impose simple hardware and cheap actuators in form of magnetorquer coils. These conflicting requirements are fulfilled through development of novel attitude and control algorithms and wide on-board autonomy. The entire control and attitude determ...

This paper presents the use of the predictive fuzzy logic controller (PFLC) applied to attitude control system for agile micro-satellite. In order to reduce the effect of unpredictable time delays and large uncertainties, the algorithm employs predictive control to predict the attitude of the satellite. Comparison of the PFLC and conventional fuzzy logic controller (FLC) is presented to evaluat...

Magnetometers are widely used for LEO small satellites attitude determination and control system. In order to estimate satellite dynamics and control attitude accurately, scale factor and bias of magnetometer must be estimated. In this study a linear Kalman filter (LKF) based algorithm for the estimation of magnetometer biases and scale factors is proposed. Proposed algorithms are simulated thr...