Patent ID: 8117888

Claim:
A method of calibrating the accuracy of a 3-axis accelerometer comprising the steps of: a) holding the 3-axis accelerometer in an orientation and relatively still to the earth; b) obtaining 3-axis accelerometer outputs, V x , V y , V z , for each respective axis x, y, z; c) equating outputs V x , V y , V z to gravitational force of 1 g according to the equation, 1 =G x 2 ( V x −V xo ) 2 +G y 2 ( V y −V yo ) 2 +G z 2 ( V z −V zo ) 2 ; where G x =gain of the 3-axis accelerometer along the x axis; G y =gain of the 3-axis accelerometer along the y axis; G z =gain of the 3-axis accelerometer along the z axis; V x0 =zero-g output of the x axis; V y0 =zero-g output of the y axis; V z0 =zero-g output of the z axis; d) solving the values of G x , G y , G z , V x0 , V y0 and V z0 ; whereby subsequent 3-axis accelerometer output is treated by the values of G x , G y , G z , V x0 , V y0 and V z0 to obtain the component force vectors, a x , a y , a z , along the axes of x, y and z, according to the relationship: a x =G x ( V x −V x0 ); a y =G y ( V y −V y0 ); and a z =G z ( V z −V z0 ).