When using imagery as a source of metric measurement, an up-front task that must be accomplished is determining the exact position (X, Y, Z) and orientation (Pitch, Yaw and Roll) of the camera at the precise time of each image exposure. This seven tuple of data is termed the dynamic exterior orientation (DEO or often simply EO) where time (the first of the seven parameters) is usually provided (but not always‼) by some external event such as a camera trigger. There are a number of algorithms for determining the position and orientation of the camera that require various external information such as known positions on the ground.
With our long background in photogrammetry, and the expectation of mapping customers, we knew from the beginning that our small Unnamed Aerial System (sUAS) would require direct geopositioning. Direct geopositioning onboard the sensor platform means that you do not have to use or at least you can minimize the use of ground control points.
Read Complete Article: The AirGon Sensor Package, Revision 3