South Australia-based DroneMetrex has reliably and repeatedly created maps at 25mm absolute topographic accuracy in height, using its in-house developed TopoDrones. According to the company, no other manufacturer of unmanned aerial vehicles (UAVs) has claimed such an accuracy, neither relative, nor absolute.

The company is able to achieve this because it has built a proper photogrammetric system from the start and then adapted it to an airframe. Additionally, DroneMetrex has addressed issues arising from camera geometry errors that are introduced through the natural physics of flight of a small airframe.

Any such drone flights will produce rapid and aggressive movements of the camera array in tip, tilt and yaw – plus forward and side image motion. If these movements are not eliminated during image capture, then large, random errors proliferate, which no amount of post-processing software can rigorously solve.

DroneMetrex have successfully resolved these issues with in-house developed hardware and software. Additionally, the company has addressed both forward- and side-motion compensation in image capture.

Tom Tadrowski, Executive Director of DroneMetrex, states: “The TopoDrones are unmatched for mapping accuracy, can be flown autonomously and manually. So for mapping, you start the input with a near-nadir, no-crab, motion-blur-less image. Isn’t this the fundamental input for any accurate photogrammetric mapping?”