Skeye BV from the Netherlands and Fugro Maps completed an aerial topographic survey using a fixed wing drone in the desert south of Abu Dhabi in the United Arab Emirates. Fugro’s client insisted on a rapid project execution meaning that the survey was carried out in the middle of summer. With measured temperatures in the sun of up to 68 degrees centigrade this must truly be the hottest drone survey ever executed.
The area to be surveyed was approximately 15 km2 and consisted entirely of sand dunes in the dessert. The reason for the survey is future industrial development. Skeye and Fugro obtained permission to fly from the UAE General Civil Aviation Authorities to operate an unmanned fixed wing aircraft equipped with a camera over the area. Skeye choose to deploy the Hawk-Eye fixed wing aircraft in a white body so as to minimise overheating of the components during the survey.
The team deployed to the desert consisted of 2 cars, 2 quad all terrain bikes, drivers, surveyors and a pilot all mobilised to a base at about one hour drive from the survey area. The drivers and all the crew had followed special desert training procedures to ensure the safety of the team. An ample supply of drinking water proved to be crucial as the Skeye pilot alone consumed over two litres per hour. The first task on the ground was the installation of the ground control markers and measuring these using RTK GPS. More than 60 ground control points were installed and a few hundred verification measurements were made for quality control purposes.
The drone flights in the heat proved to be a real challenge. The Hawk-Eye UAV had to be cooled using the air-conditioning inside a car prior to take off. The loading of the flight plan and some other checks also had to be done in the car. Within a couple of minutes of taking the UAV out of the car it had to be launched. During the flight the drone was cooled by the air flowing around it.
4100 images were collected in a special pattern to ensure sufficient overlap for photogrammetric calculations. From the images a point cloud, a 3D digital terrain model (DTM) and one seamless orthophoto-mosaic were produced.