Patent ID: 6923390

Claim:
A guidance system for providing steering control of a swing arm boom assembly for a center pivot irrigation system having a main arm water conduit with one end pivotally connected to a central point of water supply at a known location and supported on at least one movable tower, said system further comprising: (a) Said swing arm boom assembly including a water conduit supported by a drive tower having: (1) a generally horizontally aligned cross beam; (2) an upstanding wheel strut assembly located proximate each end of said cross beam; (3) at least one steerable wheel associated with the lower end of each strut assembly; (4) a steering assembly including a steering motor and means operatively connecting said motor to said wheels; (b) means for controlling said steering assembly to cause said drive tower to travel along a preselected path of travel, said control means comprising: (1) satellite signal receiving means, including a first GPS receiving antenna rotatably mounted on said swing tower, in a position that is continuously in front of at least one of said steerable wheels such that the position information received by said receiving means from said first antenna reflects locations that said one steerable wheel is moving toward when the drive tower is moving in a forward direction so that deviations of said swing tower from said predetermined path of travel are minimized; and (2) computer means associated with said receiving means to process position information from said receiving means to determine the position of said first antenna with respect to said preselected path of travel and provide an appropriate steering signal as a result thereof.