The tachymeter survey instrument has long been used by mapping and survey specialists for photogrammetry and initial measurement of points to determine horizontal directions, vertical angles and slants. However, the new Aibot X6 from Aibotix in Kassel, Germany, may change this approach in future. The Aibot X6 is a hexacopter built on an intelligent copter platform, distinguished by easy handling and a high degree of robustness. It was developed “in order to fit highest requirements of industrial inspections and surveys.” Due to the accurate management of the camera resolution and the control of speed, direction and position, the Aibot X6 captures a cartographic area through reinterpretation of the conventional photogrammetry hence 3D-models and orthophotos will be of the highest quality.
The advantages of the Aibot X6 were tested by Asker Oppmaling AS in Norway at a quarry near Oslo with a size of 33 ha. Asker compared the ground control points which were measured conventionally with the ones taken by the Aibot X6. The outcomes of this test were impressive and should make the work of surveyors much easier and time efficient according to Aibotix. “We can control the Aibot from a central location which saves us the laborious walk through the cavern,” said Magnus Myhre, General Manager, Asker Oppmaling AS. With a conventional survey method with the survey done by the Aibot X6 it quickly becomes clear that the copter will be well-established in the industry. Taking this quarry example just the normal survey time would take three to four weeks. The surveyors have to walk through the mine on foot in order to collect the data. Muddy or unstable areas are very hard to access, so most of the time they cannot be measured so some data gets lost. This is compared to the method with the X6 where all data can be collected.
The copter has a width of 1.05 m and a height of 0.45 m and can reach areas which are usually difficult to access without problems. It is also able to carry an additional payload of up to 2.5 kg and has, due to its extremely light CPR frame, a weight of only 2,555 g. The consequence of this size and weight is enormous flight stability which enables it to get results even with strong winds. The symbiosis of six rotors and the powerful motor guarantee strong lift and a stable flight altitude. The copter reaches a climb rate of 8m/sec and a speed of 60 km/h. In addition the Aibot can be controlled from a central location.
The workflows of mapping with the Aibot X6 are simple. In the preparatory stage the requirements have to be defined. The ground resolution is practicable from 1 mm up to 4 mm. Parameters like flight height, speed, overlapping and distance of the trigger position can be planned in very short time using the flight planning software AiProFlight from Aibotix. The project requirements of Asker added up to an area of 33 ha and a pixel size of 22.7 mm. After the requirements have been set the actual flight plan is constructed in order to collect the data. The flight planning is done with AiProFlight. Flight direction, resolution, height, route and stereo overlapping are defined and inserted in the mapping device. The flight plan will be constructed and saved by mouse click. At any waypoint extra requirements like camera position or dwelling time can be inserted. As soon as the flight plan is transferred to the Aibot X6 (wireless) it can operate 100% automatically. In a normal surface flight the pictures will be taken at a 90° vertical down angle (nadir). One of the unique features of the Aibot X6 is the rotatable camera mount which generates a very detailed resolution of the vertical quarry walls at an angle of 45° (oblique). Picture-based 3D-modelling software like AgiSoft or Enso then uses geo-referenced pictures and builds the texture of an orthophoto or a 3D-model. A cost-intensive camera calibration is not necessary.
