Patent ID: 7844378

Claim:
An apparatus for steering a vehicle in order to guide a farm implement along a desired path, comprising: a compensation computer having a first sidehill computer to compute a roll height compensation from a fixed function of a roll angle of said vehicle and a height of a global navigation satellite system (GNSS) antenna disposed on said vehicle; and a second sidehill computer to compute a sidehill tracking compensation from a variable sidehill tracking function of said roll angle, said variable sidehill tracking function determined to compensate a sidehill tracking error at least partly due to implement sidehill drift; and a sidehill compensator to determine a compensated crosstrack error based on said desired implement path, GNSS position measurements derived from GNSS signals received in said GNSS antenna, said roll height compensation and said tracking compensation; said compensated crosstrack error to assist steering said vehicle in order to guide said implement to said desired path.