Docking Sensor and Guidance System for Unmanned Micro-Satellites

One of the issues most fundamental to the design of an autonomous satellite docking system is the ability to be able to accurately and robustly estimate relative position, velocity, attitude and angular velocity, in all six degrees of freedom (DOF) between the transfer vehicle (chaser) and target spacecraft from ranges of 50-100km down to 100mts of the final approach. The proposed innovation in this SBIR effort is the development a low cost autonomous satellite-docking sensor based on Time Modulated Ultra-Wideband (TM-UWB) technology integrated with a supervised intelligent control approach for steering during the final approach. The proposed docking sensor will precisely determine relative position and attitude (RPA), in all six degrees of freedom, between the target spacecraft and the transfer vehicle. In our Phase I effort we will also develop a nonlinear controller to robustly track a 6DOF final approach trajectory. Techniques based on feedback linearization and backstepping will be exploited in the design of our controller. The sensor and the controller will be integrated into an autonomous intelligent guidance and control system for docking that will handle the tasks of optimal trajectory generation, fault tolerance, collision avoidance and interaction with a ground based controller.