Author(s): Alton B Moody
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 19, Number 4
Pages: 338 - 343
Cite this article: Moody, Alton B, "CELESTIAL FIX-INTERNAL OR EXTERNAL?", NAVIGATION, Journal of The Institute of Navigation, Vol. 19, No. 4, Winter 1972-1973, pp. 338-343.
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Abstract: CELESTIAL NAVIGATION is still in wide use, as indicated be sales of the Nautical and Air Almanacs. One of the questions that has intrigued celestial navigators has been the identification of the most probable position when more than two lines of the position are available but do not have a common intersection. If the total spread of azimuth is less than 180 degrees and the error of each line of the position is assumed to be equal in magnitude and of the same sign, positive or negative, the fix is external to the triangle, in contrast to the usual internal fix determined by assuming minimum error equal in magnitude alone. An analysis of 100 fixes from observations made from known positions by candidates for the N rating of the U.S. Power Squadrons indicates a definite superiority of the internal fix.