The idea behind inertial navigation is to keep track of the missile's position by constantly measuring its acceleration. By integrating the acceleration, you get the velocity. And by integrating the velocity, you get the position.
This sounds like it couldn't possibly work (surely all the little errors compound?) but apparently it's how Apollo navigated
This sounds like it couldn't possibly work (surely all the little errors compound?) but apparently it's how Apollo navigated
https://wehackthemoon.com/tech/inertial-measurement-unit-mec...