Patent ID: 8240186

Claim:
A method for calibrating sensors of an apparatus comprising a plurality of sensors and a controller coupled to the plurality sensors, the method comprising the steps of: sampling with the apparatus at least four data points to obtain measured field values; performing with the apparatus a mathematical operation to obtain offset values; and correcting with the apparatus the measured field values with the offset values to calibrate the apparatus, wherein the mathematical operation step comprises solving for (xo, yo, zo) the offset values, R = ( 1 n ⁢ ∑ i = 1 n ⁢ [ ( x mi - x 0 ) 2 + ( y mi - y 0 ) 2 + ( z mi - z 0 ) 2 ] ) 1 / 2 where x mi is the measured field value in the x-direction, y mi is the measured field value in the y-direction, z mi is the measured field value in the z-direction, x o is the offset value in the x-direction, y o is the offset value in the y-direction, z o is the offset value in the z-direction, R is the radius of the sphere on which all the nominal data points lie, and n is the number of data points.