Dead Reckoning

Dead reckoning (DR) is a method of navigation in which a ship (and later, aircraft) seeks to determine its bearings. Starting from a known position, the pilot tracks the course and speed of his vessel over a precise period, making some adjustment for drift. Celestial navigation devices are not employed, except to make corrections ("fixes").

Dead reckoning has always been plagued by inaccuracy, especially when used over long periods and distances. Such factors as ocean currents, wind and the difficulty of accurately gauging speed, contribute to error.

In general, modern-day, inexpensive global positioning satellite (GPS) devices and other electronic gear have made dead reckoning the preserve of maritime historians and hobbyists.

Off-site search results for ""dead reckoning""...

Straight Dope Staff Report: Is "dead reckoning" short for "deduced reckoning"?
... of "dead reckoning." The first citation in the Oxford English Dictionary for "dead reckoning" (spelled thus) is from 1613. In fact, in all of the OED's citations, the modifier is always spelled "dead." In the earliest dictionary entry I could ...
http://www.straightdope.com/mailbag/mdeadreckoning.html

The Biography Channel - Biography Index
... Koresh David Lynch David Seaman Davy Crockett Dead Reckoning: Fire And Metal Dead Reckoning: Invisible Clues Deadly Attraction Deadly Doctors Deadly Ladies Infamous Murders Deadly Women: Greed Dean Martin Death In The Country Death Row ...
http://thebiographychannel.co.uk/biography.htm?letter=3

The Columbus Navigation Homepage
Columbus's Navigation Columbus and dead reckoning navigation. Columbus and celestial navigation. How long was Columbus's league? Columbus and longitude. Columbus's ships. Columbus's crew. Columbus's log. Where was Columbus's first landing place ...
http://www.columbusnavigation.com/index.shtml