The development of unmanned aerial vehicles (UAVs) and continuous price reduction of unmanned systems attracted us to this
research. Professional measuring systems are dozens of times more expensive and often heavier than "amateur", non-metric UAVs.
For this reason, we tested the DJI Phantom 2 Vision Plus UAV. Phantom’s smaller mass and velocity can develop less kinetic
energy in relation to the professional measurement platforms, which makes it potentially less dangerous for use in populated areas.
In this research, we wanted to investigate the ability of such non-metric UAV and find the procedures under which this kind of UAV
may be used for the photogrammetric survey. It is important to emphasize that UAV is equipped with an ultra wide-angle camera
with 14MP sensor. Calibration of such cameras is a complex process. In the research, a new two-step process is presented and
developed, and the results are compared with standard one-step camera calibration procedure. Two-step process involves initially
removed distortion on all images, and then uses these images in the phototriangulation with self-calibration. The paper presents
statistical indicators which proved that the proposed two-step process is better and more accurate procedure for calibrating those
types of cameras than standard one-step calibration. Also, we suggest two-step calibration process as the standard for ultra-wideangle
cameras for unmanned aircraft