3DroneMapping recently completed a fairly simple aerial survey in the Democratic Republic of the Congo. The 60ha site is adjacent the Congo River and has amazing views of of Kinshasa, the capital city as well as Brazzaville in neighboring Republic of the Congo.
The survey required orthophoto and contour production. After geodetic observations were done to ensure accurate absolute geolocation, a fixed wing RPAs was deployed to capture high resolution images of the site. Since PPK (Post-Processing-Kinematic) was utilized in flight, only a few quality assurance points were placed and verified against.
In terms of processing, the flight tracklog and camera events was reduced to the calculated control system ad then photogrammetrically rendered. The end orthophoto and DSM was checked against the pre-placed quality assurance points. These showed an acceptable deviation of 0.04m horizontally and 0.06m vertically. Raw point clouds were extracted from the data and subjected to automatic and manual classification routines. These routines extract all non-ground features such as vegetation, powerlines, dwellings, etc and highlight X,Y,Z points that represent the topography or earth surface.From these ground points, a DTM was triangulated and contoured.
This very simple survey was hampered by the extremely expensive costs of site mobilization, bureaucracy, bribes and poor security. At the last moment, the project almost did not go ahead due to political instability in the region. Despite no applicable laws or restrictions regarding RPAS in the DRC law, the lack of tends to have negative effects on flight operations since the military and other stakeholders now have reason to persecute and condemn, as acts of treason, espionage or terrorism.