Apparatus and method for determining the position of a work implement

Abstract

An apparatus for determining a position of a work implement of a work machine in a site coordinate system. The position of the work implement is defined as the position in the site coordinate system of two fixed points located on the work implement. The apparatus includes first and second position sensors mounted on the work implement. A pitch sensor connected to the work implement senses a pitch of the work implement and responsively produces a pitch signal. A cross slope sensor connected to the work implement senses a cross slope of the work implement and responsively produces a cross slope signal. A rotation sensor connected to the work implement senses a rotation of the work implement and responsively produces a rotation sensor. A controller, coupled to the first and second GPS receivers, the pitch sensor, the cross slope sensor and the rotation sensor, receives the first and second position, pitch, cross slope, and rotation signals, determines the position of the work implement in the site coordinate system as a function of the first and second position signals and the pitch signal if the first and second position signals are valid and determines the position of the work implement in the site coordinate system as a function if one of the first and second position signals and the pitch, cross slope and rotation signals if an other of the first and second position signals is not valid.