The present disclosure is directed toward a system for autonomously landing an unmanned aerial vehicle (UAV) within an unmanned aerial vehicle ground station (UAVGS) and removing a battery assembly from within the UAV while landed. In particular, systems described herein enable a battery arm to engage a battery assembly and remove the battery assembly from within the UAV. Additionally, the battery arm can include one or more sensors that detect a pattern of sensor contacts arranged on an end of the battery assembly. In particular, the sensors on the battery arm can detect and identify the battery assembly based on the particular pattern of sensor contacts on the end of the battery assembly.