This article describes a simulator of small satellite attitude environment and dynamics, complete with a set of realistic sensors and the most commonly used actuator in this class of satellites. The simulator described is useful in attitude estimation and control algorithm development. Some results of the simulation of the PoSAT-1 satellite are presented.

Global nonlinear dynamics of various classes of closed loop attitude control systems have been studied in recent years [1]. Closely related results on attitude control of a spherical pendulum (with attitude an element of the twosphere S2) and of a 3D pendulum (with attitude an element of the special orthogonal group SO(3)) are given in [2], [3]. These publications address the global closed dyna...

Journal of Applied Mathematics and Computational Mechanics, Prace Naukowe Instytutu Matematyki i Informatyki, Politechnika Częstochowska, Scientific Research the Institute Computer Science, Czestochowa University Technology

In this paper, we present results on the implementation of a hierarchical quaternion based attitude and trajectory controller for manual and autonomous flights of quadrotors. Unlike previous papers on using quaternion representation, we use the nonlinear complementary filter that estimates the attitude in quaternions and as such does not involve Euler angles or rotation matrices. We show that f...

A simple analytical approach for formation-keeping of satellites in the presence of both orbital and attitude requirements is developed. A leader satellite is assumed to be in a J2-perturbed circular reference orbit and each follower satellite is required to stay in its prescribed, desired orbit with respect to the leader satellite, and at the same time, to point to an arbitrarily chosen specif...

Structural flexibility in spacecraft can degrade the accuracy of the attitude control system. With this motivation in mind, we compare the performance of inertia-free attitude control laws for a spacecraft with an undamped discrete flexible mode and demonstrate robustness with respect to unmodeled spacecraft dynamics and actuator saturation. First the equations of motion are derived using Lagra...

Several innovations are introduced to ameliorate error in space object attitude estimation. A radiometric measurement noise model is developed to define the observation uncertainty in terms of optical, environmental, and sensor parameters. This reduces biases in the space objects’ posterior state distributions. Additionally, a correlated angular rate dynamics model is adopted to decouple the ef...

This paper deals with the attitude estimation of a rigid body equipped with angular velocity sensors and reference vector sensors. A quaternion-based nonlinear observer is proposed in order to fuse all information sources and to obtain an accurate estimation of the attitude. It is shown that the observer error dynamics can be separated into two passive subsystems connected in "feedback". Then, ...

The Modelica Space Flight Dynamics Library has been developed as a unified environment to be used throughout the design cycle of the Attitude and Orbit Control System (AOCS) for a generic multibody, possibly flexible, spacecraft. The library architecture has been recently redesigned, exploiting at its best Modelica’s reusability, flexibility and modularity features. In this contribution the mai...