Sharjah to Fujairah Road
Skeye and Fugro Maps carried out a large aerial survey for a 65-kilometre road corridor running from Sharjah to Fujairah in the United Arab Emirates using a small fixed wing drone.
The first half of the proposed route ran right across the desert, whereas the second half crossed some high inhospitable mountains with peaks up to 600 meters above sea level.
The aim of the aerial drone survey was to produce 3D digital terrain models as well as one seamless orthophoto mosaic. The technique used for the aerial survey was photogrammetry where terrain heights can be extracted from a series of overlapping images.
Skeye choose to operate the small fixed wing drone UX5-HP from Trimble. The reason for doing so is the fact that this fixed wing UAV is equipped with GNSS PPK processing capabilities. As a result the positions where the photographs are taken can be accurately calculated by simultaneously logging GNSS data at a base station on a known location. Once the positions of the photographs are accurately determined then fewer ground control points are required. The latter was very difficult in this mountainous area and the choice to use PPK positioning was an obvious one.
Contrary to popular belief that no ground control points are required Skeye choose to install and measure these points at every kilometre along the route. In addition many verification points were measured to check the accuracies of the end deliverables.
The project was not without challenges. The first and most obvious one was the encountered heat (well in excess of 50 degrees centigrade). Prior to every flight the aircraft had to be cooled inside one of the vehicles using the air-conditioning. Once all the parts were properly cooled then the UAV had to be launched within minutes otherwise it would heat up. This restricted the number of flight hours per day. Usually the team had to stop working by 11 am every day.
A second challenge was the proximity of the first part of the route to Sharjah Airport. In collaboration with Air Traffic Control certain small time slots were allocated to carry out the flights.