SparkFun Electronics Forum

Interesting article jremington. That does raise the question if the lsm303 is the right module for the job? Or are there modules that would do a better job?

The Vectronix Digital Magnetic Compass (DMC) is perhaps the most accurate on the market. With a 12 point calibration procedure it is accurate to a few tenths of a degree in a non hostile magnetic environment. Of course you have to pay for that accuracy (~$3,000 USD).

The application note from ST Microelectronics suggests that the best you can do with this hardware, after tilt compensation, is +/- 2 degrees. http://www.pololu.com/file/0J434/LSM303 ... p-note.pdf This is not bad for a ~ $30 breakout board.

Here is a much more comprehensive article by a pilot, who also discusses what the professionals do for long range navigation. http://myahrs.wordpress.com/2012/04/20/ ... uld-do-it/ Needless to see, he is pretty emphatic that devices like the LSM303 aren't up to the task of guiding passenger-carrying aircraft.