The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't.
In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was.
The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.
In any given moment of time, the missile most likely knows which of the following?

A) Where it is
B) Where it isn't
C) Where it was
D) Where it wasn't
by QWERTY mnbvcxz September 19, 2019
The nickname you give a soccer player that just kicks the ball as hard as he can without thinking when the ball comes to him.
Hey, look at Missile over there! He has the ball! (5 seconds later) Oh wait, the ball is 100 feet out of bounds now.
by Dallin G December 7, 2016
In downtown baltimore, a missile is most commonly an awesome bag of raw heroin. If it's of a good quality and there's a good amount, then it's a missile. This term is also used to refer to other drugs, but mainly heroin. In the last year or so it has seen repeated use as a replacement for "the bomb". In this context it can be used to describe anything of an exceedingly high quality.

I once was buying a bag of weed and had it broken down for me by a native. I commented the bag was a bit small, and he replied to me, and I quote:
"don't even worry about the size, baby, it's a <i>missile</i>"

I asked him what that meant and he told me it was like the bomb, except it gets shot straight into your nose/lungs/veins.

A nuclear missile is better than a regular missile.
That dope I got from Jimmy The Hat was a fucking missile, I shot up yesterday and I'm still fucking wasted!
by AmoebicMagician May 14, 2009
a weapon i wish i had to shoot my school
i will shove a missile up the principle's ass
by Dan shithead November 29, 2003
Anything that is really really good looking or tasty.
After B.Y. mixed his Crystal light water pack into his bottle and took a swig he said, " Man that was a missile, Cuz."
by Eleandrus February 4, 2011