I am using ORB-SLAM3 with a monocular camera on a drone for Augmented Reality application. I need to know the absolute scale of the map formed by the SLAM.
I cannot use a stereo or RBG-D setup. Tthe scale of the monocular SLAM is defined every time the SLAM is started. Can someone please suggest any ideas how can I get the scale factor/ absolute scale of the map?
Can GPS be used to do this? To measure the distance between points in GPS co-ordinates and the corresponding distance in SLAM map and just divide those to get the scale factor?