Technology: Laser guide for aerial crop sprayers

 作者:司寇挛     |      日期:2019-02-28 07:16:01
By JEFF HECHT A military laser imaging system designed to warn helicopter pilots of obstacles has been adapted to control pesticide spraying in orchards. It can cut the volume of spray by up to 40 per cent, so saving farmers money and cutting pollution. Schwartz Electro-Optics of Orlando, Florida, originally developed the system to pick out ground targets for US Army gunners. It then adapted the technology for mounting on the helicopter rotors. The system sends out low-power laser pulses and times the delay before the reflections return. From this it builds up a radar-like picture of nearby objects that warns pilots when they come too close to wires or trees. After developing this system, Schwartz was approached by another Florida company, Agspray, to adapt the sensor to control tree spraying. Schwartz engineers modified the helicopter transmitter so that the laser beam scans a plane perpendicular to the direction of travel. In this plane, the laser emits pulses at one-degree intervals. As the helicopter moves through the orchard, laser reflections from trees within 9 metres of the sprayer are converted into images. The laser system looks for trees along the path of the sprayer and shuts off its nozzles when there is no foliage close enough to be sprayed. This keeps the ground between the trees free of pesticide. Schwartz is talking to several companies interested in adding the laser sensors to their spray trucks. The company estimates that the laser system will cost less than $10 000. Farmers and spray operators using the system should be able to recoup that cost through savings on wasted pesticide. They would also limit pesticide pollution,