The Rendezvous and Docking (RVD) System in IITBSSP aims to pioneer a simulation framework for Guidance, Navigation, and Control for autonomous rendezvous and docking of one 6U CubeSat, called the chaser, to another, called the target; under the purview of GNC subsystem.
The tasks for this system are divided into three sections -
A standard RVD mission is broken up into four phases. Here’s how we’re going to work with each:
After the launch, the chaser and target are very far away separated by a certain phase angle. In this phase, we aim to minimize this phase angle and the relative distance between the two and also correct the launch injection errors. Absolute Navigation takes place here. Selected technique - Special point maneuver using simulated annealing for solving optimization problems to minimize the amount of fuel used.
Far Range Rendezvous -
In this phase, the Chaser moves from the orbit at the end of phasing to a point in the close vicinity of the Target, in the same orbit. Relative navigation starts in this phase. Selected Guidance technique - Hoffmann Transfer
Close Range Rendezvous -
Here, the Chaser moves extremely close to the Target, using relative navigation techniques, and aligns itself to be ready for docking. Selected Guidance Technique - ZEM/ZEV
In this phase, the Chaser moves along a fixed direction to finally attach itself to the docking port of the Target. In our mission, we are only concerned with Soft Docking. Vision-Based Navigation is employed here to find the relative orientation of the two satellites. Selected position and attitude control technique - Model Predictive Control.
Currently, the system is engaged in working to design and implement the selected algorithms in the context of the mission statement.
Feel free to reach out to us if you have any doubts or interesting conversations to make regarding RVD!