MOISTURE MANAGEMENT ▶▶▶ Professor Jeff Walker
Autonomous drone improves irrigation
Engineers from Australian Monash University in Melbourne are using autonomous drone technology to improve irrigation practices. Eventually the drone technology will be used to reduce the use of water and optimise yield.
P BY RENÉ GROENEVELD
rofessor Jeff Walker from the Australian Monash Univer- sity has been working on soil moisture mapping through remote sensing for more than 15 years. “Nasa, European Space Agency and the Japanese space agencies have
had soil moisture teams for their various satellites,” he explains. “But the challenge of these satellite missions has been course res- olution. It was really too course for agriculture. My idea was: how can we help agriculture and improve on this?” Walker emphasises that Australia is one of the driest continents on earth and is becoming even drier with global warming. “We were wondering how we could bring improved mapping technol- ogy to farmers in a way that they need it. Basically the way to im- prove this spacial resolution is moving the technology closer to the ground.”
Farmers do not have the time to stand around and fly drones all day
Optical technology The team of Monash University started with optical technology to make sure the concept worked. “We used it as a stepping stone to microwave technology,” says Prof Walker. He explains that the full
30 ▶ FUTURE FARMING | 24 May 2019
system should work autonomous. “I am not focusing on the flying function at the moment, although I think that is an important step and can be easily done. Having said that, there are regula- tions at the moment that preclude this. But hopefully going for- ward we will be able to go around those regulations.” In the tests with optical technology Prof Walker and his team have been focusing on an autonomous soil moisture mapping system for irrigated paddocks. There were tests at a dairy farm using a cen- tre pivot irrigator and at a crop farm using a linear shift irrigator. Prof Walker: “We made some moisture maps and compared those to ground measurements. We demonstrated that it is possible to get autonomous maps.”
Microwave sensing A farmer first has to identify the field, for example on a Google Earth type image. The system will then automatically determine the height of flying, the flight lines and other necessary specifics. “You can effectively press the go button and it will fly, collect the data, come back, automatically download the data and run it through the processing stage,” says Prof Walker. “It will then pro- duce a map. That map can be fed into the irrigation system to optimise the water delivery.” In the past two years Prof Walker and his team performed tests with optical cameras. Now the team focusses on passive microwave sensing technology on drones, using L-band waves. The team is planning to start tests with a L-band microwave system in Septem- ber. “It will give us a far more accurate picture than the optical map- ping did. Vegetation will not affect the picture of the soil too much.” In the long run the team wants to use P-band microwave technol- ogy. “The P-band is a longer wave again,” he says. “The vegetation will be almost entirely transparent using P-band. Also the depth
PHOTO: RENÉ GROENEVELD
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