DEIT

Surveying - Photogrammetry

Surveys usually form the foundation of every project. Classic images of the situation as-is are derived from Total Station, GNSS and a terrestrial laser scanner. Flights were until recently only made for larger areas, as flight hours in manned aircraft are expensive, and so too the associated equipment. As such, it was only practical to use aerial photography for areas over 5 km² in size. Hand in hand with substantial improvements in digital photography, processing software and affordable computer performance, as well the development of unmanned, remote-controlled aircraft, it is now finally possible to provide flights over small areas, using terrestrial photogrammetry, in a fast, precise and affordable manner! Naturally, there are certain limitations: problems can arise, for example, in areas of dense vegetation or over flat, reflective surfaces. Yet for many areas the advent of drones and digital cameras has provided the first affordable solution to capturing the desired data.

Survey Coanda Mk.AD

In early 2018 we decided to consolidate our fleet with uniform batteries, remote controls, flight controls and flight planning software. April 2018 brought the delivery of Survey Coanda Mk.AD by Soleon and it will be the successor to Surveying Robot Mk.AD for future photogrammetric projects.

Helicopters

When legal or time constraints prevent the use of drones, we can also use a helicopter to gather the necessary images for photogrammetric processing. From the well-secured open cabin door, the project area will be photographed as per the appropriate overlapping. The exposures are then logged by “Image Vector” (made by REDcatch) to facilitate later processing.

A disadvantage of using a helicopter is the relatively imprecise flightplan, as even an adept pilot finds it nigh on impossible to maintain a steadily consistent distance to the ground. As such, a helicopter flight can often produce a very unhomogenized level of ground sampling distance.

UAV planner 3D

The problem with surveying flights is that it is relatively easy to plan such a mission in 2D: the overlap in the X and Y directions are at hand and the altitude remains constant. On flat land, this represents a simple exercise in geometry.

However the Earth is unfortunately not always as flat as the plains of Northern Germany. For precisely this reason, we have developed a tool with which you can also create plans for flights over hilly and mountainous areas.

Our goal was to keep the distance to the photographed object constant, regardless of whether the incline is 0° or 90°. Only in this way can we be sure that the overlapping and geometric resolution remain constant during the whole flight.