dead-reckoning position

Dead reckoning is a navigation technique used to determine a ship's or aircraft's position without relying on external references like celestial navigation. It involves calculating the current location based on a known starting point, the courses or directions traveled, and the estimated speed or distance covered.1

Navigators differentiate between the dead-reckoning position (based on course steered and speed through water) and the estimated position (which includes corrections for factors like current and wind). Because the accuracy of dead reckoning decreases over time, celestial observations are periodically used to establish a more reliable position, known as a fix, from which a new dead reckoning process begins. Modern systems often use dead-reckoning computers and inertial guidance systems, which measure acceleration to calculate velocity and position.12