Relative Velocity Estimation in a Cluster of CubeSats by Differential GNSS

The paper compares two Kalman Filters (KFs) to complement Real-Time Kinematic (RTK) method with a relative velocity estimate in the framework of CubeSat formation flying in Low Earth Orbit (LEO). One KF is a standard constant velocity implementation, whereas the second KF include relative dynamics through Hill’s model. Both filters are intended to support GNSS-based closed loop real-time onboard orbit control of relative separations in a cluster of CubeSats implementing the concept of Distributed Synthetic Aperture Radar (DSAR).