CS ROMANIA has implemented the OrbiPro toolbox, an accurate orbital propagator for modelling the effect of various perturbations for GNC and AOCS systems, as a contract for ESA (European Space Agency).

The availability of an accurate propagator is of primary importance for knowledge of the trajectory and attitude of a spacecraft and in particular for the computation of the orbit of a spacecraft around Earth or other main celestial bodies in our Solar System, the trajectory of a spacecraft during interplanetary missions or the evolution of the formation of several satellites, as well as in the case of rendezvous.

OrbiPro is a Matlab® toolbox that is able to perform accurate and high-fidelity numerical propagations taking into account a wide list of perturbations such as central-body gravitational field and potential with spherical harmonics (up to a user-defined order), tides, third-body perturbation (for all meaningful solar system bodies), solar radiation pressure (taking spacecraft shape and attitude into account, the distance from the Sun and the shadowing effects), atmospheric drag (taking spacecraft shape and attitude into account), planetary albedo and infrared (IR) radiation and forces induced by manoeuvers (impulsive and constant or variable thrust).

OrbiPro computes the spacecraft’s attitude either by means of a predefined law (Nadir pointing, with possible Yaw compensation with respect to ground velocity or Yaw steering with respect to Sun; Celestial body center pointing, with possible spin; Fixed Cardan offsets with respect to Local Orbital Frames LVLH, VVLH or VNC; Inertially fixed; Tabulated from a file) or by using the spacecraft’s inertial matrix and integrating the contribution of several torques like the gravity gradient torque, the geomagnetic disturbance torque, the aerodynamic torque and the solar radiation torque.

OrbiPro offers the possibility of detecting a wide number of events during propagation, like: eclipse (both umbra and penumbra), ascending and descending node crossing, apogee and perigee crossing, alignment with some body in the orbital plane (with customizable threshold angle), raising/setting with respect to a ground location (with customizable triggering elevation), date, altitude crossing, impulse maneuvers occurrence and it also provides the possibility of slightly shifting the event occurrence time (useful when some decisions must be made before or after the exact moment of an event).

Also, independent on the propagation itself, OrbiPro is able to use a pre-defined trajectory and attitude profile defined by the user and provide as output the corresponding global perturbing force and torque.

OrbiPro was validated against the open-source library Orekit and the results showed consistency between the two implementations.

A presentation of OrbiPro toolbox results will be done at KePASSA 2017 conference, organized at ESTEC on July 25-27, 2017.

More details about this conference are presented here.

Presentation of OrbiPro toolbox at KePASSA 2017 conference, on July 25-27