Theses and Internships

The interaction between the satellite and earth magnetic field plays a very important role in the on-orbit dynamics simulations. The magnetic field has to be accurately modelled and simulated in the laboratory environment. The static and dynamic behaviour of magnetic fields generated by the Helmholtz cage and the satellite mock-up have to be characterized. This work can be divided in the following parts:

• Modelling of the on-orbit magnetic field as function of the orbit parameters and time.
• Characterization of the Helmholtz cage as a function of the control input and the disturbance rejection capabilities by means of magnetic field sensors.
• Estimation of the residual dipole of the satellite and dynamic behaviour of the system through the simulations.

The performance of an attitude control system depends greatly on the accuracy of the input data. The data provided by IMU as well as by other sensors available on the attitude dynamics simulator must filtered before they can be profitably employed in the control loop. Different filtering and estimation techniques have to be implemented and tested to guarantee the best possible performance given the available hardware. The work can divided as follows:

• Study and implementation of filtering algorithms for IMU in Matlab and Arduino programming languages.
• Attitude determination by means on combination of different sensors, such as Sun sensors, Earth sensor, gyroscopes and .
• Experimental testing in a real-time application, such as attitude and inertia matrix estimation.

The actuators for nanosatellite have to comply with very strict requirements due to the limited available space, weight and power. However, the performance requirements could be very strict and different actuations have to be compared and analysed before the satellite design. As part of the work, development and testing of a simple actuator have to be done. According to the mission requirement, magnetorquer, mass shifter, torque wheel have to be developed. Thanks to the three-axis simulator testbed developed in the laboratory, the developed hardware can be experimentally tested.

Given the availability of a Sun simulator within the testbed, the proposed activity consists of the design and prototyping of a miniaturized sun-sensor for nanosatellites.

 Infrared Horizon Sensors (IHR) are commonly employed onboard of small satellites, as they provide information on the nadir-direction by detecting the infrared Earth limb. An IHR prototype is currently under development at the laboratory: the proposed activity consists of developing an Earth simulator (such as an heated disc) to be integrated within the attitude dynamics testbed for testing the IHR prototype.