Patent ID: 6880643
Filing Date: 2005-04-19
Classification: E02F

Abstract:
1. A system for providing a flat grade to guide alteration of land, the system comprising: a first antenna operable on an earth moving machine, the first antenna operable to receive signals from a satellite navigation system; and a computer responsive to the signals received by the first antenna, the computer operable to determine a position of the first antenna relative to a planar surface tangent to the Earth as a function of the signals from the satellite navigation system; wherein the computer is operable in first and second modes of operation, the first mode of operation corresponding to calculating an elevation of a work implement to correspond to the flat grade relative to the planar surface tangent to the Earth, and the second mode of operation corresponding to calculating the elevation of the work implement to correspond to a curved surface approximating a surface of the Earth, the first mode of operation different than the second mode of operation.