An off-road vehicle comprising: a chassis; a plurality of ground-engaging elements for supporting the chassis on a ground surface and propelling the vehicle along the ground surface; a power source for driving movement of at least one of the ground-engaging elements; and a control system configured as an indirect self-tuning regulator to provide automatic guidance for the vehicle by automatically steering the vehicle via at least one of the plurality of ground-engaging elements, the control system configured to - hold a representation of a vehicle system process, apply an estimator to determine a plurality of vehicle system process parameters, the estimator using at least one value (u) generated by the control system and at least one measured vehicle output (y) to determine the plurality of vehicle system process parameters in real time during vehicle operation, determine a second order linear closed-loop reference model based at least in part on user input parameters (ωn, ζ), determine a plurality of control parameters using the vehicle system process parameters and the reference model, regardless of changes in ground surface conditions, hitch forces and vehicle velocities, determine a guidance input according to the control parameters, a setpoint ( β̇) of a desired output, and said at least one measured vehicle output (y), and use the guidance input to automatically guide the vehicle. a chassis; a plurality of ground-engaging elements for supporting the chassis on a ground surface and propelling the vehicle along the ground surface; a power source for driving movement of at least one of the ground-engaging elements; and a control system configured as an indirect self-tuning regulator to provide automatic guidance for the vehicle by automatically steering the vehicle via at least one of the plurality of ground-engaging elements, the control system configured to - hold a representation of a vehicle system process, apply an estimator to determine a plurality of vehicle system process parameters, the estimator using at least one value (u) generated by the control system and at least one measured vehicle output (y) to determine the plurality of vehicle system process parameters in real time during vehicle operation, determine a second order linear closed-loop reference model based at least in part on user input parameters (ωn, ζ), determine a plurality of control parameters using the vehicle system process parameters and the reference model, regardless of changes in ground surface conditions, hitch forces and vehicle velocities, determine a guidance input according to the control parameters, a setpoint ( β̇) of a desired output, and said at least one measured vehicle output (y), and use the guidance input to automatically guide the vehicle. apply an estimator to determine a plurality of vehicle system process parameters, the estimator using at least one value (u) generated by the control system and at least one measured vehicle output (y) to determine the plurality of vehicle system process parameters in real time during vehicle operation, determine a second order linear closed-loop reference model based at least in part on user input parameters (ωn, ζ), determine a plurality of control parameters using the vehicle system process parameters and the reference model, regardless of changes in ground surface conditions, hitch forces and vehicle velocities, determine a guidance input according to the control parameters, a setpoint ( β̇) of a desired output, and said at least one measured vehicle output (y), and use the guidance input to automatically guide the vehicle.