External Compass Integration with Reach & Pixhawk

Hi! I’m planning out my next Pixhawk build utilizing REACH and I couldn’t find any documentation regarding an external compass. The GNSS unit I’ve used previously has an external compass which I need because of the mounting proximity to my ESCs. Any advice?

The easiest option would be to use an external compass connected over i2c, any board with HMC5983\HMC5883L will do. They are widely available at <10$.