A high-resolution map created by orthophotos, usually via drones is termed as an orthomosaic. Ortho meaning a
nadir image and mosaic meaning a collection of images.
Aerial surveys use a measuring camera where the elements of its interior orientation are known, but with much larger
focal length and
film and specialized
lenses.
Aerial survey sensors
In order to carry out an aerial survey, a sensor needs to be fixed to the interior or the exterior of the airborne platform with line-of-sight to the target it is
remotely sensing. With manned
aircraft, this is accomplished either through an aperture in the
skin of the aircraft or mounted externally on a wing
strut. With
unmanned aerial vehicles (UAVs), the sensor is typically mounted under or inside.
Aerial survey systems are typically operated with the following:
Flight navigation software, which directs the pilot to fly in the desired pattern for the survey.
GNSS, a combination of
GPS and
inertial measurement unit (IMU) to provide position and orientation information for the data recorded.
Gyro-stabilized mount to counter the effects of aircraft roll, pitch and yaw.
Data storage unit to save the data that is recorded.
Examples of aerial survey sensors
Vexcel UltraCam (Eagle,[3] Falcon, Osprey,[4] Condor) and their calibrations.[5]