Imagery geo-referencing is performed by vendors. Aerial imagery is geo-referenced
through accurate recovery of the imaging optical perspective center position (X0/Y0/Z0) and
aim angle (κ/φ/ω), either through the AT process or from direct IMU measurements. Spaceborne
imagery is similarly geo-referenced by correlating data from platform ephemeris (the
record of imaging positions/time) and sensor attitude (aim angles referenced to a star field).