dead reckoning n. Koppeln, Navigation durch Berechnungen; die Position eines Schiffes oder Flugzeuges mit Hilfe der Berechnung der Geschwindigkeit erzeugt (Babylon)

Dead Reckoning is the process of estimating your position by advancing a known position using course, speed, time and distance to be traveled. In other words figuring out where you will be at a certain time if you hold the speed, time and course you plan to travel. The Chinese discovered that a needle with a magnet on one end always pointed the same direction, north. At least now they could know what direction they were headed in, and if you knew that and you multiplied your speed by your time spent traveling you could deduce your position. This is called 'Dead Reckoning' and was used regularly well into this century. However it wasn't terribly accurate since it relied too much on estimates of speed. (Dead Reckoning Aviation Navigation)

Dead Reckoning bezeichnet die laufende Ortsbestimmung (Ortung) eines Schiffs oder Flugzeugs durch Messung von Kurs, Fahrt (Geschwindigkeit) und Zeit, siehe Koppelnavigation GB: Dead reckoning (DR) is the process of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known or estimated speeds over elapsed time, and course. While traditional methods of dead reckoning are no longer considered primary means of navigation, modern inertial navigation systems, which also depend upon dead reckoning, are very widely used. (wikipedia)