Algodoo

ETA - how long it will take for the shells to get there.
Distance - The distance away from the cannon, max is 3000 meters/1.86 miles.
Angle - Whether the angle is low or high.

Controls:
Enter - fire.
1 - Switch between low and high angle.
Arrow keys - control test car.

Notes:
Position tracker is the red thing on the test car. It can be detached and moved by different methods (airplane, rocket, etc).

To look at the actual cannon zoom out all the way, you will see a big red box. Follow that box all the way back and below it you will see the cannon.

It's accuracy is within 2 meters.