The vehcile heading is defined as in Figure 10. North is zero degree. Vehicle has positive heading in counter-clockwise direction and negative value in clockwise direction.
Figure 10. Definition of Vehicle Heading
The steering angle is defined as the angle between the front of the vehicle and the steered wheel direction as shown in Figure 11. The steering system has a maximum (minimum) steering angle of +0.52359878 (-0.52359878) radians or +30 (-30) degree.
Figure 11. Definition of Steering Angle