Heading magnetometer HMC5883L, tilted.

Other Hardware Sensors
1

Hi!
I am using I2Cdevlib to interface with both an MPU6050 and HMC5883L (autopilot sometime in the future). The library is really great, but there is a problem.
Whenever I want to calculate my heading from the magnetometer I don't know how unless the sensor is close to flat. Is there a way I can calculate the heading when the sensor is not flat on the ground? Since I want to make an autopilot for an airplane I can count on it being level all the time. Tilting the magnetometer with the regular algorithm running gives huuuge errors.

Any help is greatly appriciated!

2

Quaternions.

3

so u'll need accelerometer info in addition.. to tell orientation. and of course: u need to know how the magnetic field is orientated at your location.

4

This document explains in great detail how to use an accelerometer+magnetometer to create a tilt-compensated compass: http://cache.freescale.com/files/sensors/doc/app_note/AN4248.pdf There are simpler approaches than those described, though.