From setpoint application rate and the current land rate, the setpoint flow rate is determined. The VRT system attempts to achieve the setpoint flow rate, and correspondingly, the setpoint application rate. The flow rate at any given time is the actual or response flow rate which correspondingly determines the actual or response application rate. The application rate error is the difference between the setpoint application rate and the actual application rate. It is almost always nonzero.
Spatial resolution is the smallest area which can receive a distinct and desired application rate.
It is the product of lateral resolution and longitudinal resolution . Lateral resolution is normal to the direction of travel. Lateral resolution is simply the width of each individually controllable element of the application machine. Longitudinal resolution is the smallest travel distance in which a desired application rate can be achieved and maintained. It is the product of the travel speed of the vehicle and the minimum time required for the control system to achieve and maintain the desired application rate.