Wheel Angle Sensor for big Machines

Hi. I am new to Ardupilot and Rover.

I like to steer a little tractor with a mover.

yuri mower steers with the 2 motors (slow fast) https://www.youtube.com/watch?v=NjaIKyrInpg

how the steering of a tractor could be done. do i need a wheel angle sensor and some hard/software
to have straigt running und convert output to my tractor.

Did you ever figure out how to incorporate wheel angle sensor into Ardupilot for tractor?