Got Gyro drift? Try Sensor Fusion !

[StevenB]

Thanks for sharing! I think this raises the entry point for autonomous localization and navigation, which is great.

Originally Posted by Richard100

The Mag cal values are strongly a function of where the sensor is located on the robot, and what is installed nearby, so it's important to recalibrate fairly often, certainly after relocating the sensor, and again after the robot is completely assembled. Be sure you actuate all motors and mechanisms to test for interaction with the Yaw indication, which uses the Mag. Be aware that another robot that comes close to the Magnetometer might disturb the local magnetic field enough to cause error in Yaw – the solution to this difficulty is left to the enterprising student of sensor fusion.

I think I'd be more worried about transient magnetic fields due to my own electrical system, rather than other robots.

The strength of Earth's magnetic field is about 40-50 microtesla [wikipedia]. The magnetic field due to current in a wire is 2e-7 * I / r, where I is current in amps, and r is the distance in meters. Say you're within 33cm of a wire. That's 0.6 microtesla/amp, and if you've got a drivetrain that pulls 60+ amps (forward and backwards), you've suddenly got a 70+ microtesla swing that will overwhelm the field you're getting from the earth. The thing that scares me about this is that it will kinda-mostly work when you're doing simple testing (without a real robot, or under light load), and start going bizerk when you try it on the field.