Patent ID: 7953550

Claim:
A method for determining a position of a rotatable arm of a center pivot irrigation system, comprising: providing a pivot arm position sensing system including a tower unit positionable on the rotatable arm of the irrigation system at a position spaced from a center of rotation of the rotatable arm, the tower unit including a Global Positioning Satellite (GPS) receiver; receiving, from a user of the irrigation system over a communication network, a schedule for operating the irrigation system as the rotatable arm rotates, the schedule including at least two instructions for taking an action by the irrigation system, each instruction including an action to be taken by the irrigation system and corresponding location coordinates at which the action is to be taken, downloading the schedule of instructions over a wireless communication network to storage on the position sensing system; determining location coordinates of the tower unit as the tower unit moves along a path of the tower unit as the rotatable arm pivots about the center of rotation using the GPS receiver on the tower unit; and initiating an action by the irrigation system by the position sensing system when the location coordinates of the tower unit correspond to the location coordinates in one of the instructions stored on the position sensing system.