Use of a Small Computer as a Celestial Navigation Aid

Abstract

This paper concerns use of a computational device by ships' navigation officers to improve the efficiency of celestial fix taking operations. The objectives are to reduce the demands placed on the officers' time by present manual computation procedures and to reduce the loss of night vision caused by exposure to high illumination levels. Computational procedures are defined for presetting the sextant and for determining a line of position from one sextant observation. Successive applications of the procedures for two or more sightings will provide a celestial fix. Data from the Nautical Almanac are entered into the computer by the operator via a keyboard at appropriate points in the computation sequence. A small electronic digital computer suitable for performing the necessary computations is described. Special wiring of the computer memory converts the computer from a general purpose calculation tool to a special purpose navigation device tailored to the needs of the navigation officer. However, capability is retained for using the computer in alternate modes for other shipboard functions when it is not in use for fix-taking.