Eagle-eye photos | New spin on precision agriculture gives agronomists an alternative to satellite imaging
WOODSTOCK, Ont. — Satellite imaging is an important tool for agronomists, but sometimes the clouds get in the way.
“Satellites fly over five to 10 days. You get clouds sometimes. Then five to 10 days to get results,” said Felix Weber of Palmerston, Ont., who advises farmers on managing their land and crops.
“Meanwhile, your crop has been dealing with problems you could have been working on.”
Weber, who recently attended Canada’s Outdoor Farm Show in Woodstock, started thinking about ways to get those images without using a satellite or a light plane.
“Drones,” he said. “I looked at quite a few of them.”
One of the planes Weber looked at was Swinglet, built by SenseFly of Switzerland, where he was born and raised.
The company builds the equipment and software that allows images made by the flying camera to be geo-referenced. Tying the images to exact land locations gives them value for farmers because they can be layered with other maps to create precision agriculture prescription maps or locate trouble spots in fields that need scouting to establish nutrient deficiencies or pest problems.
The 500 gram flying camera is made of Styrofoam with a hardened outer shell. With a wing span of 80 centimetres, the rechargeable, swappable battery-powered flying wing relies on a rear-facing prop to get it airborne.
“Its light weight means that it can land on its own without damage,” said Weber.
Flight planning takes little time or training. The operator places a rectangle on a digital satellite map and a flight plan is automatically created. If no geo-referenced maps are available, the software can accept way-points to be placed over the map.
The unit takes wind into account and operates in light wind up to 25 km/h.
It creates images that overlap and are digitally tagged as to their location with six to 10 cm accuracy.
Standing in a field in Ontario’s Oxford County, Weber gave the plane a quick shake and its gyroscope, recognizing the instruction, initiated the take-off sequence and the motor spun to life. With a light push the flying camera left Weber’s hands and rose to 125 metres at a rate of about three metres per second.
The Swinglet can work as high as 3,000 metres, but that puts the machine potentially in the path of light planes and should be discussed with Transport Canada.
The higher the unit flies, the greater the distance it can scan.
It can create images over 10 sq. kilometres in half an hour, but the area is reduced at lower altitudes. However, lower altitude flights increase the resolution and detail in the final image.
The Singlet’s 2.4 GHz communication system will talk to the ground station, maintaining its geo-referencing functions for up 1.3 km. It will continue to shoot if it gets out of range, but it will lose its GPS locations on the images.
The plane will return and land within 20 metres of its take-off site once the camera has completed its mission or there are errors.
Glue can used to make most repairs, although Weber said they don’t happen often.
“They have such low mass that even hard landings don’t hurt them,” he said after retrieving his Swinglet from the edge of a corn field.
A digital fence ensures that the plane will automatically return to is launch area no matter what problems are encountered.
A radio controller comes with the plane for manual flight control, but Weber said it isn’t necessary and is provided only to meet international regulatory requirements for autonomous aircraft. The ground software can be placed on a tablet or laptop computer and provide a visual monitor of the imaging process.
Images are stored on an SD card and downloaded from the card to a computer when the unit lands.
The software then knits the images together to create a continuous map that is fully geo-referenced. It can also make 2D and 3D terrain profile maps, which are useful in precision farming field analysis and variable rate crop and nutrient planning or for planning an EC mapping of potentially saline soils.
“It’s a tool,” he said.
“I see it as something that farmers can make use of.”
The autonomous flying cameras cost about $14,000 and aren’t for hobbyists, but Weber said the investment pays off rapidly when used to provide immediate insight into crop conditions. The units are also used by engineers and others who rely on precisely located aerial photos.
For more information, contact Weber at 519-343-5454 or email him at [email protected]