The unmanned system for this project was a small electric quadcopter (four prop rotor system) custom built with Mikrokopter brand flight control and navigation components. An on board GPS system provided position control and a gimbaled camera mount stabilized the camera for vertical photography. Flying a UAS with the University required applying for an FAA Certificate of Authorization (COA). We did the online paperwork and our project was approved (2013-ESA-16-COA).
The system is designed to fly autonomously to a pre-programmed set of waypoints and with our equipment and camera the approximate flight time on a battery was 15 minutes. We planned for less than 12 minutes for each flight to provide a margin of safety. All required equipment was boxed in a waterproof case for transport to the island by local fishing boat. We did two trips, covering the West half April 26, 2013 and the East half May 04, 2013.
Using software from Mikrokopter waypoint flight grids were planned over seven separate sections of the island. The altitude was set at 40 meters and maintained by a barometric altimeter built into the flight control system. The camera was triggered manually through a switch on the radio transmitter (not automated with this design). The plan was to take at least two photographs per waypoint to assure at least one quality photograph at each point and provide enhanced stereo coverage for later 3D modeling. Prior to each flight the waypoint grid was uploaded to the UAS from a laptop computer. A map on the computer allowed tracking the flight in real time and the option to take control if required.
The flight opportunities were limited to the time before the nesting Terns arrived in the May and after they departed in September. Of the two days we flew our times on the island were limited to about three hours because wave conditions required early departure by the boat. The seven flights provided complete coverage of the island with additional off nadir photographs for visuals.
The flight data and control parameters, including coordinates and camera bearing, were recorded and stored onboard the Mikrokopter as GPX text files using an SD card in the flight controller. These data were later downloaded and used for processing the position information for the photographs. Follow the link below for details.