Magnetic Field Sensor calibration on ANDROID

Question

I'm making an application that works as a compass..

I'm using the accelerometer and the magnetic field sensors to compute the azimuth angle through, sensor.getOrientation().

I'm searching for something that can improve the magnetic field sensor accuracy, since I'm getting it state of accuracy as UNRELIABLE!

Any one knows anything about this?I'm looking for something that can be either hardcoded or for instance just physically moving the phone until it gets calibrated!

Answer 1

This is not a final answer (I don't know anything for sure), but my understanding from online posts is that waving the phone around in a figure of 8 a few times while the compass is in use is supposed to trigger automatic recalibration. This is what the google maps app suggests, for example. I don't know whether this is dependent on application functionality (something in maps that detects the waving by accelerometer and triggers a recalibration), or something in the android stack, or something specific to per-phone implementations. Try it and see!

Eg discussion: http://androidforums.com/epic-4g-support-troubleshooting/217317-cant-get-compass-calibrate.html

This reference appears to suggest this per-axis / figure-8 rotation process is built-in functionality: http://m.eclipsim.com/gpsstatus/

And here another article that claims this is built-in functionality, and that you don't even need to be running a compass-consuming app for the recalibration to work: http://www.ichimusai.org/2009/06/20/how-to-calibrate-the-htc-magic-compass/