Dynamics and Control of Distributed Spacecraft Systems

Robert Zickel (collaborator), Konstantin V. Kholshevnikov (collaborator), David Mishne (collaborator), Marc-Phillipe Rudel (research staff), Igor Beigelman (grad student), Yossi Elisha (grad student)

:: Distributed space systems lab: We have established a testbed for developing distributed space systems and sparse-aperture interferometers. The lab includes a unique air-bearing table for simulating a frictionless environment and four satellite models carrying magnetometers, accelerometers and laser range finders. LOS-only control yields cooperative motion. Each RoboPuck carries a low-grade mirror for testing new concepts in sparse aperture imaging. Inter-communication is implemented using ZigBee. More details can be found on the DSSL website.

:: Optimal formationkeeping, modelling and visualization of spacecraft formations: This research is devoted to optimal formation-keeping of multiple-spacecraft formations, and developing a concomitant STK-based visualization and simulation package for modelling spacecraft relative motion.

:: The relative motion manifold and metrics: What is the minimum, maximum and mean distances between spacecraft flying in formation and subjected to astrodynamical perturbations? This project, performed in cooperation with Prof. Kholshevnikov from St. Petersburg University, provided some of the answers.

:: Satellite collision avoidance using GNSS positioning: Formation flying missions must be equipped with collision avoidance mechanisms. As part of the GEO6 project, we are working on designing such systems using GNSS signals, and validating the technology using the GRACE mission telemetry.

:: The performance of EGNOS: Using a GPS/EGNOS receiver, we are examining the integrity and perfromance of EGNOS in the mediterranean region. See MEDaCoN's website.

Applied and Theoretical Astrodynamics

Michael Efroimsky (collaborator), Sergei Kopeikin (collaborator), Valery Lainey (collaborator), Dmitry Pisarevsky (research staff), Dani Meltzer (grad student),  Eytan Brucker (grad student), Sofia Belyanin (grad student), Ariel Vaknin (grad student), Gali Nir (grad student)

:: Stationkeeping in the restricted three-body-problem: Designing a stationkeeping methodology for spacecraft flying on orbits about the collinear Lagrangian points. The model includes the effects of eccentricity, fourth-body dynamics, oblateness and fourth-body inclination.

:: Attitude dynamics in the restricted three-body problem: Examining the gravitational effect of the third-body on the passive stabilization of spacecraft flying on libration point orbits, inclduing the modified stability regions under a third-body perturbation.

:: Low-energy transfers to distant orbits of the Earth: Designing a  method for analytically characterizing orbits for deep-space science missions, known as Distant Retrograde Orbits.

:: Orbits for space telescopes: The resolution of mid-IR space telescopes is impaired by the zodiacal dust cloud. Going above or below the ecliptic plane dramatically improves the diffraction limit due to IR scattering. This research looks into efficient ways of putting a spacecraft on out-of-ecliptic orbits.

:: Astrodynamical modelling and analytical study of geostationarry satellites:The increasing lifetime of GEO satellites poses new challenges for astrodynamicists. One such challenge, for instance, is modelling the effect of equinoctial precession on the long-term dynamics of communication satellites and space debris.

:: Long-term behavior of orbits about precessing planets: Using semi-analytical modelling of time-varying equinoctial precession and a myriad of other orbital perturbations, determine the long-term faith of natural satellites orbiting precessing planets (e.g. Deimos and Phobos). A multi-year collaborative project perfromed with Dr. Michael Efroimsky of USNO and Dr. Valery Lainey of the Royal Observatory of Belgium. 

:: New methods for relativistic modelling of the two-body problem: The gauge freedom of the planetary equations (discovered by Dr. Efroimsky), can be used to simplify the astrodynamical modelling of the parameterized post-Newtonian effect on satellites. This project is perfromed in collaboration with Dr. Efroimsky of USNO and Dr. Kopeikin of UMC. 

Dynamical Systems and Optimization Theory

Anthony Bloch (collaborator), Dan Butnariu (collaborator), Yair Censor (collaborator), Michael Efroimsky (collaborator), Antonio Elipe (collaborator), Kai-Yew Lum (collaborator), Itzik Klein (research staff) 

:: Application of gauge symmetry to improving numerical integration: It can be shown that variational transformations exhibit symmetry which may be utilized to reduce the local integration error of the Runge-Kutta method, as well as stabilizing the Euler explicit method.

:: The feasible control method: This is a project in cooperation with Prof. Yair Censor from the University of Haifa, who developed numerical algorithms for solving convex fesibility problems. These methods are implemented on real-life control problems to yield a useful tool for system optimization.

:: The Serret-Andoyer project: It turns out that a canonical representation of rigid body dynamics may provide much insight into modelling and control of rigid-body dynamics. We are pursuing a few problems in this regard. Some of the work is performed in collaboration with Prof. Anthony Bloch from the University of Michigan and Dr. Efroimsky from USNO.

Communication and Coordination of Multiagent Systems and Sensor Networks

Dimitri Kanevsky (collaborator), Avishy Carmi (reseach staff), Sharoni Feldman (research staff), alexei rosich (grad student)

:: Decentralized coordination and communication of UAVs: Our group is conducting research on cooperative motion of multi-agent systems. See media coverage.

:: Cooperative Prarafoils: Endowing guided parafoils with the ability to inter-communicate may significantly improve the chances of successful airdrop. A technology for communication and autonomous task assignment of cooperative parafoils is being developed as part of the FastWing CL Project.    

:: Sensor networks: A technology for efficient routing in very large scale wireless sensor networks is being developed, as well as efficient acoustic detection methods using Baum-Welsh algorithms. This project is an ongoing collaboration between Dr. Dimitri Kanevsky (IBM Watson), Avishy Carmi (currently at the University of Cambridge) and Dr. Sharoni Feldman (Technion and IAI).    

Vision-Based Navigation and Control 

Ehud Rivlin (collaborator), Hector Rotstein (collaborator), Ronen Keidar (collaborator), Oshra Belpolsky (grad student), Shai Segal (grad student), Vadim Indelman (grad student)

:: Navigation system performance enhancement using online mosaicking: Some aerial vehicles are equipped with cameras capable of building a mosaic image of the environment. This research examines whether this process can be used as an auxiliary mechanism for pose estimation and autonomous vision-based path planning.

:: Vision-based localization of a lunar satellite: Autonomous navigation in fututre lunar missions can be accomplished using onboard cameras and computer vision algorithms. This research models the astrodynamical environment of the moon and develops autonomous lunar navigation algorithms using image-based localization theory.

:: Vision-based control of relative spacecraft dynamics: Computer vision can be used to regulate the relative attitude and position between satellite both in the cooperative and non-cooperative cases. This research examines whether stereoscopic vision can be used to achieve these goals, and to what degree of accuracy.

:: Autonomous vision-controlled quadrotor for indoor navigation: A collaborative project between the Distributed Space Systems Lab and the Intelligent Systems Lab (CS, Technion), aimed at designing a micro-rotorcraft capable of autonomously navigating indoors using vision sensors.