Test - 57north-discuss

20 Oct 2021

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.