|
When the Transit system first came out I heard something like this, which applies equally to GPS:
The satellite navigator never knows where it is, but always knows where it isn't. To determine where it might be, in a format useful to a third party, it subtracts where it was yesterday from where it hopes to be tomorrow and applies correction factors based upon what it thinks the wind, tide, current and auto-pilot are doing at any given moment. The result should never be relied upon for navigation purposes when out of sight of land.
|