Patent ID: 8634993

Claim:
A spray control method for controlling spraying of a material on a spray zone of a field also including an exclusion zone which is not to receive said material, said spray zone being separated from said exclusion zone by a spray turn-on boundary when passing from said exclusion zone to said spray zone and by a spray turn-off boundary when passing from said spray zone to said exclusion zone; said method employing a spray vehicle including a material tank, a pump communicating with said tank, and a nozzle communicating with said pump, said pump when activated causing said material to be sprayed from said nozzle to a spray range from said nozzle and requiring a turn-on lag time between activation of said pump and said material reaching said spray range and a turn-off lag time between deactivation of said pump and cessation of said material being sprayed from said nozzle, said vehicle having a GNSS receiver mounted thereon at an offset distance from said nozzle and outputting position data representing a position of said receiver, said receiver being interfaced to a controller which is interfaced to said pump, said controller selectively activating said pump and having data representing said turn-on boundary and said turn-off boundary stored therein, and said method comprising the steps of: (a) moving said vehicle in said exclusion zone toward said turn-on boundary at a vehicle velocity; (b) communicating position data from said receiver to said controller to track the position of said receiver; (c) activating said pump by said controller when said receiver detects a position of said receiver within said spray zone at a spray turn-on distance beyond said turn-on boundary equal to the sum of said offset distance plus said spray range minus the product of said vehicle velocity times said turn-on lag time; (d) moving said vehicle in said spray zone toward said turn-off boundary; and (e) deactivating said pump by said controller when said receiver detects a position of said receiver within said exclusion zone at a spray turn-off distance beyond said turn-off boundary equal to said offset distance minus the product of said vehicle velocity times said turn-off lag time.