Integrity for Satellite Space Corridor

The significant increase in number of satellites and continuing creation of space debris in LEO (Low Earth Orbit) (e.g. mega constellations) is significantly increasing the risk of collision between space object, that could create a cascading chain of events, potentially leading to the loss of operative satellites and to the creation of even more space debris. For this reason, the concept of Space Corridors has been proposed in the past. However, up to today there is no integrity concept embedded into the Space Corridor to guarantee that possible issues (e.g. current position is outside protection limits) are identified and immediately flagged/corrected. Therefore, ESA (European Space Agency) launched the ISCO (Algorithms for Space GNSS Guaranteed Positioning: Integrity for Space Corridor), project led by GMV, to provide this extra layer of integrity to the Space Corridor concept, in a unified approach, including feared events impacting satellite ODTS (Orbit Determination and Time Synchronisation). The space corridor concept is defined as the mechanism assuring that the satellite instantaneous position is maintained within a predefined “control box” without intervention from the mission ground segment (thus on-board and autonomous). The objectives of this paper are to present the research, design and implementation of the Integrity concepts supporting guaranteed position and velocity in the Space Corridor for autonomous manoeuvres and demonstrate its performance through model in the loop simulations. To achieve the objectives integrity concepts have been reviewed and adapted not only to cover the position, velocity and time of the spacecraft, but also the propagation/forecast of its orbit After performing a trade-off and a devoted fault analysis, three integrity algorithms are proposed. These three algorithms are based on the adaptations of terrestrial concepts to space users, taking into account their particularities. Then, the overall integrity concept will be tested for three different use cases, representative of a wide variety of satellite users.