BGS has recently acquired an unmanned aerial vehicle (UAV) for close-range aerial photography of geoscience subjects. The results of initial evaluation flights are described below.
The BGS shallow geohazards and EPOM teams have collaborated to acquire a six bladed, electric powered, radio controlled (R/C) helicopter (Hexakopter™). This has been trialled at Bradgate Park (Leicestershire) and at BGS'slandslide field observatory at Hollin Hill (North Yorkshire). Its use in low-level photogrammetry, for example with a pair of calibrated stereo cameras, and also with scientific micro-sensors (e.g. gas detection, magnetometry, infra-red) is being actively pursued.
The Hexakopter has attitude, azimuth, GPS position and altitude control, allowing it to remain stationary in flight, wind conditions permitting. The maximum payload is 1 kg. Radio control functions and waypoints can be programmed via laptop connection to the aircraft (pre-flight) if required, and photos or video downloaded. The camera's shutter and tilt angle are controllable in-flight. The aircraft can be launched and retrieved by hand, enabling it to be used in confined locations whilst minimising the risk of camera damage. Flight duration depends on payload, wind and temperature, but is typically 10 to 15 minutes per battery charge. Currently, UK regulations state that for this type of UAV the operational ceiling is 400 ft, the aircraft has to remain visible throughout the flight and cannot be used in built-up areas or close to the public, hence the Hexakopter's suitability for the types of remote or rural locations encountered in most geoscience applications.
Cliff retreat at Aldbrough is occurring at approximately 2 m per year (East Riding Council). This occurs in several modes of landsliding. These include rotational slumping, toppling failures and minor mudflows, all of which are initiated due to the action of the sea. A 3D model derived from Hexakopter photography illustrates one such landslide at Aldbrough in the East Riding of Yorkshire. Due to the rapid deployment of the Hexakopter, future landslides can be rapidly imaged and modelled, producing and capturing a time sequence of landsliding at Aldbrough. The Aldborough 3D model 8.57MB pdf is available for download.