MAG3110 and FXMS3110 for greater accuracy

[vitaliysiplichu]

Hi!

Does anybody use two magnetometers in one device to get more accuracy result? If somebody does then can you explain to me how to use it? For example we have soft and iron calibration, so how to use datas from two different mag sensors in that computations?
Or maybe I should make two independent computations for each sensor and then take the average result? But it seems to me that it's not the right decision...

[Joshevelle]

Hello Vitaliy,

Thanks for using our community.

Using two magnetic sensor would not increase the accuracy of the heading angle, the only difference between them would depend on each specific sensor offset.

I would rather recommend you to add an accelerometer and a gyroscope. For instance, you could use the FXO8700 which is a magnetometer and an accelerometer in a single package and the FXAS21002 which is a 3-axis gyroscope, that would imply a 9-axis sensing solution. We also have free software libraries ready to use. For detailed information, please take a look at the following URL:

www.freescale.com/sensorfusion

hope it helps!

Josh

[vitaliysiplichu]

Thanks, Joshevelle!
I've got it!
But what about second reason to have two magnetometers: as I understand in that case we can make our mesurments right after power on without calibration or something like that. Is it true?

[Joshevelle]

You are very welcome Vitaliy.

I don't see how two magnetometers could help to take the measurements without calibration. As you said, you could read both sensors outputs and take the average results, however without a calibration routine you would read two wrong measurements and have a wrong average result. Honestly, I don't think that it would be helpful.

-Josh