There is always cone on uncertainty around the missile position and speed and interceptor position and speed. Both the missile and interceptor must meet at the

There is always cone on uncertainty around the missile position and speed and interceptor position and speed. Both the missile and interceptor must meet at the same place at the same time. The time window decreases with speed, so timing is everything. Faster the incoming missile, harder it is to intercept. If the speed delta between incoming missile and interceptor is to high, interceptor can't correct it's course fast enough to hit the missile. Interceptor has inertia and it's deflectors or thrust vectoring can correct it's course only so fast. Interceptor positioning on the ground is also important.