I believe they have applications in missle guidance systems. I cannot remember what it's called but essentially given a target position in space the missle use

I believe they have applications in missle guidance systems. I cannot remember what it's called but essentially given a target position in space the missle uses parametric data about its current position/orientation/speed and their higher derivatives to dead reckon about where it is in regards to the target. Anyone remember what that's called? I went on a rabbit hole with it a few years ago, it's really interesting math and programming. Everything works basically stateless except for current instrument data, last position and target position from what I remember.