Check this (different devices in the topic, but methods should be similar):
Problems aiming nRAY
Which kind of compass are you using?
Wouldn't this be good enough?
https://www.ngdc.noaa.gov/geomag/calculators/mobileCompass.shtml
Check this (different devices in the topic, but methods should be similar):
Problems aiming nRAY
Which kind of compass are you using?
Wouldn't this be good enough?
https://www.ngdc.noaa.gov/geomag/calculators/mobileCompass.shtml