Calibration help required

[Clive Wallis <clivew@xxxxxxxxxxxx>]

Hi,

I wonder if someone coluld help.  am looking fo a mathmetical 
procedure to adjust the calibrations of the OSCAR-11 magnetometer so 
that the mean square of the error between the measured field and the 
theoretical field is a minimum.  I would really like to be able to do 
this on a spread sheet.

I have a table of about 3000 values of the theoretical field BT, and
corresponding measurements.

The measurements consist of two values,  N and BH.

The relationship between the measured field BM  and the measurements
is -

       BM = SQRT(BZ*BZ + I*BH*BH)

       BZ = K*N + J

I have initial values of I, J, and K which give a fairly good fit. I
believe that there may be an iterative procedure which enables optimum
values of I, J,and K to be calculated. 
 
I think that the approach may
be to obtain some linear equations by partial differentation, and
solve these by substituting statistical values obtained from the
table of data.

Any help would be greatly appreciated.

-- 
73     

Clive    G3CWV

         Hitchin, North Hertfordshire, UK.