eXom Drone Proved Capable of Producing Millimetre Accurate 3D Data

New construction survey white paper positions eXom quadcopter as a truly high-performance surveying instrument

Stuttgart, Germany (Intergeo 2015), September, 2015 – While professional drones are commonly used today in land surveying and GIS applications, it is unusual to see UAVs (or UAS) employed on construction sites for highly accurate survey work. However thanks to the accuracy reported in the senseFly white paper published today, this looks set to change.

The white paper, named Generating highly accurate 3D data using a senseFly eXom drone, presents the results of two photogrammetric land surveys of a construction site. The project was completed earlier this month (September, 2015) using two senseFly eXom close mapping and inspection drones.

The results demonstrate that 3D point clouds produced with an eXom quadcopter can reach a global precision comparable to that of a total station survey and, as such, meet the typical accuracy requirements of construction projects.

The accuracy results of the two surveys were within planimetry and altimetry expectations:
• The first eXom survey (figure 8) achieved 2.1 mm accuracy in X, 1.9 mm in Y and 0.1 mm in Z (RMSE).
• The second eXom survey (figure 9) achieved 0.8 mm (X), 0.5 mm (Y) and 4.2 mm (Z).

“This degree of absolute accuracy from a drone is unparalleled and positions the eXom as a surveying instrument that is comparable in performance to standard total stations,” said Andrea Halter, senseFly’s co-founder. “These results were due, in part, to the high 38 MP resolution and sharpness of the flight’s images, captured by the main camera inside eXom’s TripleView head. Add to this image quality the ability to operate close to the terrain and the introduction of highly precise ground controls and you have a recipe for exceptionally accurate 3D data.”

Two eXom drones flew separate survey missions at an altitude of 14 m above the site, achieving an average ground sampling distance (GSD) of 2.2 mm. All the flights were completed using the drone’s Interactive ScreenFly flight mode, whereby the UAV is controlled using a handheld ScreenFly controller connected to senseFly’s eMotion X flight planning and control software.

This flight mode’s Cruise Control feature, combined with its Auto-Trigger function, enabled each of the eXom drones to survey the 1,100 m2 site in a single flight. Meanwhile the live on-screen feedback from the drone’s five different navcams and ultrasonic proximity sensors helped the operator ensure that no contact was made with either the on-site crane or any the trees surrounding the complex site.

Halter is already looking ahead to what the eXom might achieve next. “This project’s flights took place at 14 metres above the ground, but with the eXom’s Distance Lock feature we are able to safely fly just 4 metres away, so it isn’t unrealistic to think that the accuracy we achieved could be improved still further.”

To download the eXom accuracy white paper, visit: http://bit.ly/1UOQFdj

About senseFly
At senseFly we develop and produce aerial imaging drones for professional applications. Safe, ultra-light and easy to use, these highly automated data collection tools are employed by customers around the world in fields such as surveying, agriculture, GIS, industrial inspection, mining and humanitarian aid. senseFly was founded in 2009 by a team of robotics researchers and quickly became the industry leader in mapping drones. Today we continue to lead the way in developing situationally aware systems that help professionals make better decisions. For more information, visit www.sensefly.com or follow us on Twitter, LinkedIn or Facebook. senseFly is a Parrot company and a member of the Small UAV Coalition.