Abstract: Researched the agricultural production farm machinery on-board GPS positioning problem to improve the po- sitioning accuracy. Farm machinery on-board GPS positioning vulnerable is easy influenced by fitter. The car GPS will shake when farmland long lines is not flat, causing car GPS position is not accurate, resulting the work error of agricul- tural machinery operation. The traditional linear filter on-board GPS positioning method cannot effectively remove fitter influence, causing the problem of low location accuracy. In order to solve this problem, this paper put forward the on- board GPS filter double localization method. Using activation function controls kalman filter gain and preliminary wea- kens the effect of fitter. Introducing self-adapting attenuation factor establishes a rapid response filter, and combining with the farm machinery motor change track finishes removing fitter influence, completing farm machinery positioning at last Simulation results show that this method can effectively remove shaking influence caused by unstraight long line, accuratly finish the orientation of agricultural machinery car GPS.

Key words: Linear filter, Activation function, Attenuation facto