A custom object recognition algorithm uses a Microsoft Kinect to compute relative position and attitude data of the target nozzle with respect to the capture vehicle at approximately 15 Hz. A VectorNav VN-100 IMU is used on board the capture vehicle and provides body accelerations and angular velocities at 200 Hz.
The relative measurements are used to update a Continuous-Discrete Extended Kalman Filter while the IMU measurements are used for filter propagation. A Mission Handler determines the appropriate mission phase and generates the necessary reference trajectory for the capture vehicle.
A built in feedback controller is used to calculate the necessary commands to complete an example rendezvous mission. Vehicle emulation capabilities are made possible by a separate module which allows HOMER to replicate the motion of a virtual dynamic model. The Vicon motion capture system records position and attitude data of each vehicle to serve as the experimental truth and verify individual system components.
We are pleased to acknowledge that this work was supported by NASA Johnson Space Center and would not be possible without the efforts and insight of the ADR team. We would also like to thank the Texas Space Grant Consortium along with Jeremy Davis and James Doebbler of VectorNav Technologies.