AOCS research at the Dipartimento di Elettronica e Informazione started in 1999 under my supervision, along a number of parallel activity lines, both of fundamental and applied type, and has reached the following status:

·         Spacecraft modelling and simulation: proprietary tools for modelling and simulation have been developed using the innovative object-oriented concepts for physical system modelling embedded in the well known Modelica language and the Dymola simulation environment. Such tools have been recently used in the following  studies:

o        Analysis of the AOCS for the SWARM mission (in cooperation with ESA-ESTEC);

o        Preliminary design of the ACS for the AMS-02 mission (in cooperation with Thales Alenia Space Italia);

o        Development of simulators for two new satellite platforms (in cooperation with Carlo Gavazzi Space, in the framework of the MATEO INTERREG III C project).

·         Spacecraft attitude determination and parameter estimation: both simulation and in-flight experience (design of the attitude determination system for the first Italian small satellite mission - MITA) have been gathered in the design and implementation of attitude determination systems. The current research aims at the following two objectives:

o        Investigating the potential benefits of Unscented Kalman filtering techniques with respect to conventional Extended Kalman filtering (in cooperation with NGC Aerospace Ltd and the University of  Sherbrooke, Canada) both for attitude and orbit determination purposes;

o        Studying the applicability of globally convergent nonlinear filters to the satellite attitude determination problem (in cooperation with Prof. Alessandro Astolfi and Dr. Dina Shona Laila, Imperial College, UK).

·         Spacecraft attitude control: the focus in this activity is on attitude control problems arising in spacecraft using magnetic torquers as primary or sole actuators. In particular, such problems have been and are investigated:

o        in a global perspective, in order to analyse the stability properties of magnetic control schemes in, e.g., attitude acquisition or large angles manoeuvres (in cooperation with Prof. Astolfi, Imperial College);

o        in a local perspective, using periodic systems theory in order to improve the stability and performance characteristics of magnetic-based ACS (in cooperation with Dr. Andras Varga, DLR, Germany).

o        Recent work, developed under ESA contract, aimed at exploring novel applications of magnetic attitude control such as the magnetic desaturation of reaction wheels in geostationary spacecraft and the use of this technology as a support for conventional actuators in future missions to the Jovian system.

·         Spacecraft orbit control: a number of applications have been investigated in this area:

o        Electric station-keeping techniques for geostationary satellites (in cooperation with Alcatel Alenia Space France and Ecole des Mines de Paris);

o        Stability analysis for formation-flying control algorithms (in cooperation with Alcatel Alenia Space France and Ecole des Mines de Paris);

o        Beam steering control for inter-satellite laser ranging (in cooperation with Thales Alenia Space Italia).

·         Entry, descent and landing (EDL) problems: EDL is currently one of the main challenges for the European space community, in view of the Mars missions (ExoMars, Mars Sample Return) planned for the next decade. In this field, the following activities are being carried out:

o        Robustness and worst-case analysis of the powered descent guidance, navigation and control system for the ExoMars mission (in cooperation with Thales Alenia Space Italia). In particular, methods from the field of hybrid evolutionary optimisation are being used to develop efficient tools for worst case analysis for the powered descent and landing phase of the mission;

o        Design of advanced analytical guidance laws for planetary descent and landing.

Some past activities:

Star identification and starcamera-based attitude determination: Star sensor technology is now becoming available at reasonable costs also for small satellite missions. The proper operation of star sensors is based on two equally important components: the star camera hardware and the star identification and attitude determination software. A number of different algorithms for these two important tasks are being developed and tested, with the aim of obtaining an optimal tradeoff between accuracy and performance in terms of memory requirements and computational load.

Predictive techniques for formation keeping: The problem of orbit control for a small spacecraft is being investigated within the framework of predictive control. In particular, the aim is to develop an approach capable of taking into account constraints on the control inputs, integral action for accurate steady state performance, both in the case of circular and elliptical orbits.