Vision system for mavros/local_position/pose

Hi All,

I’m trying to make a system of localization for a drone that uses a downward facing camera with a beacon reference point on the ground. The drone would take in the images of the visual beacon on the ground and would determine it’s local position using geometry based on the size of the beacon and how it is oriented relative to it.

My question is how to I find more information on how the default drone in ROS knows it’s local position and is able to stabilize itself and keep itself in the same position.