Autonomous flight sprayer drone with RTK

http://www.joyancetech.com/html/spray...

Real Time Kinematic(RTK) Differential Kit
RTK is especially designed for high-precision flight of the UAVs.

Dual antenna differential module
Cooperate with RTK differential base station to provide the cm-level position precision but also orientate the air craft precisely through double antennae.
Compared with the traditional orientation by magnetic compass, the double-antenna orientation way can eliminate the influence of magnetic interference and ensure the flight safety of the aircraft under the high voltage wire and in the mining area with strong magnetic interference.
DGPS RECEIVER AIR – Ultimate supports all existing satellite navigation systems.
The received frequencies include GPS L1, L2, L2C, GLONASS L1, L2, BDS B1, B2, and GALILEO E1, E5.
It can use the dual-frequency signals of GPS, GLONASS and BDS at the same time for positioning as well as RTK calculating.
With higher positioning accuracy, it is more widely applied.

RTK portable base station
The differential system of the portable base station consists of one-piece portable base station, data link and differential module.
In actual work, the position data of the ground base station is broadcast in real time through data link.
The differential module integrates the data from satellite and the position information received by the on board data link terminal for RTK calculation, so as to realize the cm-level high-precision positioning.

PS: RTK is expensive, and it is optional.