A novel adaptive unscented Kalman filter (AUKF) based estimation algorithm is proposed for a 3U Cubsat. This small satellite employs a three axis magnetometer and three MEMS gyroscopes as well as three magnetic torque rods and one reaction wheel on the pitch axis. Unlike the existing UKF, in this paper, an n+1 sigma set is used to estimate the nanosatellite attitude instead of 2n + 1 sigma poin...

In this paper a result on attitude tracking control of a micro satellite by integrator backstepping based on quaternion feedback is presented, and the controller is shown to render the system equilibrium point UGAS by application of the LaSalle-Yoshizawa theorem. This is a part of a study of possible control methods for the spacecraft ESEO, a spacecraft included in the SSETI project initiated b...

The Chinese BeiDou system (BDS), having different types of satellites, is an important addition to the ever growing system of Global Navigation Satellite Systems (GNSS). It consists of Geostationary Earth Orbit (GEO) satellites, Inclined Geosynchronous Satellite Orbit (IGSO) satellites and Medium Earth Orbit (MEO) satellites. This paper investigates the receiver-dependent bias between these sat...

Fractional Order Control methods were applied to a three-axis reaction wheels satellite attitude control system. To show the advantages of this method, a comparative study between a Linear Quadratic Regulator and a Fractional Order Control was established through two principal fractional control laws. The aim is to establish an efJicient control law which satisJies a given speczjication and mai...

Designing a robust tracking control for a non-linear MIMO system with uncertainty is one of the most complicated control problems. In this paper, sliding mode changed to non-linear controllable canonical form by input-output linearization. This, sliding surfaces can be defined in a way that we can de-couple equations and indicate the sliding conditions of multi-variable controller system. The u...

Abstract: An optimal reconfiguration control for satellites formation flying with attitude constraints by the use of a small number of thrusters is addressed. These thrusters are fixed to the satellite body and generate unilateral forces. This study assumes that the satellite’s attitude angle during the reconfiguration maneuver is restricted within a certain bound from a specified direction in ...

Stephen Hodgart received a Ph.D. degree from the University of Surrey. He has been with the Surrey Space Centre, since its inception and the launch of their first satellite, UoSAT-1 in 1981. He is currently visiting Reader at the University of Surrey. He was responsible for the first practical low-cost active magnetic and passive gravity gradient control attitude system for a low earth orbiting...

Designing a robust tracking control for a non-linear MIMO system with uncertainty is one of the most complicated control problems. In this paper, sliding mode changed to non-linear controllable canonical form by input-output linearization. This, sliding surfaces can be defined in a way that we can de-couple equations and indicate the sliding conditions of multi-variable controller system. The u...

The availability of new high density FPGA technologies enables innovative approaches to the architecture of onboard computer systems (OBCS) for demanding small satellite applications. In the paper, we present the architecture of a highly integrated satellite computer exploiting the powerful features of Xilinx’s Virtex-II Pro FPGA technology. The computing resources of the “Flying Laptop” satell...