Compass direction

I plan to use mu Tiny RTK in a tractor and would like to know the Compass direction the front of the wehicle stands. Is there any solution for this?
Can I use two Tiny’s and have two antennas (Front and rear)?
This instead of using a magnetic Compass.
Is there any solution ready for this that I can use?
Or do I have to calculate Compass direction by my own by Reading in the two Lat/Lon?
/Pelle

I guess that the simplest solution is to use a compass .

Drotek has an external compass that you can connect via I2C to your autopilot

So, you have no moving base solution?