Abstract
A granule applicator control system using a global positioning system (GPS) velocity sensor was developed. This sensor uses conventional single-frequency GPS to directly estimate velocities from carrier phase measurements and their derivatives by computing radial velocities between satellites and the receiver.
The developed system was tested for accuracy and applied to actual farm work. Actual application rates varied accurately with planned rates. Positioning for planned changes in application rate was accurate within 0.7m. The difference between actual and planned application rates in actual farm work was less than 10%. The system controlled by the GPS velocity sensor is now available for practical use.
