THE DIRECT FIX OF LATITUDE AND LONGITUDE FROM TWO OBSERVED ALTITUDES

Stanley W. Gery

Peer Reviewed

Abstract: This work presents a direct method for obtaining the latitude and longitude of an observer from the observed altitudes of two celestial bodies. No assumed position or dead-reckoned position or plotting is required. Starting with the Greenwich hour angles, declinations, and observed altitudes of each pair, the latitude and longitude of the two points from which the observations must have been made are directly computed. The algorithm is presented in the paper, along with its derivation. Two different, inexpensive, programmable pocket electronic calculators were programmed to execute the algorithm, and they do it in under 30 s. The algorithm was also programmed to run on a personal computer to examine the effect of the precision of the calculations on the error in the results. The findings show that the use of eight decimal places in the trigonometric computations provides acceptable results.
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 44, Number 1
Pages: 15 - 24
Cite this article: Gery, Stanley W., "THE DIRECT FIX OF LATITUDE AND LONGITUDE FROM TWO OBSERVED ALTITUDES", NAVIGATION, Journal of The Institute of Navigation, Vol. 44, No. 1, Spring 1997, pp. 15-24.
https://doi.org/10.1002/j.2161-4296.1997.tb01935.x
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