Today we passed a major milestone. We went into the field once again and flew the same transects as last time. The firmware fault in the autopilot had been corrected by our suppliers, Skycam UAV, and we were keen to collect a set of data that could be analysed by our Masters student.
Because the strip of bush that we are surveying is only 1.4NM from a commercial airfield, we need the agreement of the aerodrome operator to fly. Professor John B wrote a draft Memorandum of Understanding and submitted it to the CFI of the aerodrome operator, an established aero club. Dr. John and John B went to visit the CFI and the club manager on Tuesday to discuss the form and content of the MoU and came away with an agreed form.
Today's operation was set up in accordance with the MoU; the proposed flight path, times of operation and an annotated Google map of the area was sent to the CFI 72 hours in advance.
After arrival at the operating site, the CFI was contacted to confirm the the operation would take place. The aircraft was very carefully checked against our standard pre-flight check list, as it had not been test flown after the firmware update. All checked out and the planned track was loaded into the autopilot. The Sony NEX5-N camera was installed in the payload bay and the autopilot was set to trigger the camera every 1.8 seconds. After a short period of monitoring 118.00MHz, the aerodrome circuit frequency, a general broadcast was made to indicate that the Hawk would be launched imminently.
The launch went without incident, the GCS announced that the Hawk had launched successfully and she headed off, climbing rapidly to our operating altitude of 500ft AMSL. After the Hawk reached altitude, Navigation Mode was commanded and she headed off on the pre-programmed track. The camera was turned on and the Hawk made three transects of the bush, returning to the launch point at the end of the track. Auto-land was commanded and, after a couple of descending circuits, the parachute deployed and Hawk landed gently. We have still not cured her of her predilection for fences, but she missed it, just! (This problem is exacerbated by changing wind speed during the descent after parachute deployment, but the landing is probably more gentle than a conventional approach and slide across the ground).
With some trepidation, we removed the memory card from the camera and downloaded the images to Prof B's computer. Magic! There were 239 images on the card.
An infrared bandpass filter (720nm up) was fitted to the camera and a second flight was organised. This too went off without incident and another 213 images, this time nIR were collected.
A call was made to the aerodrome to state that the Hawk UAV operation was complete, the A/C and ground station were packed up and we headed back to Auckland Central.
There is a lot of work to do, analysing the 452 images with Pix4UAV, and we hope to repeat the operation in about a week, this time carrying our vegetation stress camera over the same flightpath,
There is quite a lot of preparation for our next sortie - charging of batteries, issue of intent to fly, arranging for the team to be available at the same time (not so easy during semester), booking the vehicle, and cleaning the mud off the equipment; it is still winter here!
Infrared Image of the bush from about 350 ft
