is there any standard for Mag calibration?

[youngguekim]

Hi. I have a question about Mag calibration.

When i give board movement to Filter, it is changed as follows. and i become to see that it is calibrated and I can get a accurate value.

is there any standard for Mag calibration?

For example, for Mag calibration, I have to move a specific sensor about 180 deg

Thank you.

[michaelestanley · Accepted solution]

There is a defacto standard for the form of the solution: 3x3 inverse soft iron plus 3x1 hard iron offset.  But there is no standard for the process of computing magnetic calibration coefficients, not even a defacto one.  The Freescale magnetic calibration functions utilize a "total-least squares" fit to compute the inverse mapping required for hard and soft iron calibration.  Basically, you need to collect enough data points on the measurement ellipsoid  (see http://blogs.freescale.com/sensors/2011/03/hard-and-soft-iron-magnetic-compensation-explained/) so that the solver can reach a numerically significant result. 

[youngguekim]

Thank you very much

[a8Chcx]

Hi Mike,

Could you let me know when you are going to fix the link for " http://blogs.freescale.com/sensors/2011/03/hard-and-soft-iron-magnetic-compensation-explained"?

I checked the other link like matrix computation as well. They are all not accessible now?

Thanks,

Christie

[michaelestanley]

Christie,

It looks like it got dropped when they merged the Freescale and NXP sites.  I don't have direct access to the site, and will have to request it be reposted when I return to the office in January.  In the meantime, I'll post a PDF of the old site in another post.  It's not pretty (the PDF formatting leaves a lot to be desired), but should help fill the gap.

Mike