Fuente: Wipo "precision agriculture" A system and method for controlling the level of a moveable first wing in a vehicle mounted spray system. The vehicle mounted spray system comprises of the moveable first wing and a moveable second wing mounted to a common support structure to form a pair of opposed independently moveable wings extending laterally from the vehicle. The method and system comprise a first step of determining an initial control signal for the moveable first wing based on a position of the moveable first wing 210, then determining a compensating signal; and then controlling the level of the moveable first wing based on the initial control signal and the compensating signal.