In this solution, what is your source for speed? Measuring rotations of the wheels or GPS?
If you can add another sensor besides the GPS, such as wheel speed or even acceleration, a Kalman filter can give good results. A simpler alternative that...
Absolute maximum rated voltage for T4.1 pins is 3.6V. if you expect the possibility of 5V, you will need something more to limit the voltage closer to 3.3V, like a zener or schottky clamp diode.