Errors of Dead Reckoning's Formula resulted from Difference of Assumption
K. Shimada · Nihon Kokai Gakkaishi/Nihon Kōkai Gakkaishi · 1962
Some formulas for converting distance on a rhumb line track into distance of latitude and longitude are approximate equations, and their errors are negligible in practical use. But in special cases, their assumptions may lead to unthinkable results. For example, in low latitude departure in Marcator's Sailing becomes greater than difference of longitude, and true middle latitude on terrestrial ellipsoid is not between two latitudes passing on two points. To research these subjects, it is necessary to take the correct equation of meridian length and departure in navigational formulas. The objects of this paper are to point out the errors of each formula in navigational Dead Reckoning computation and to discover the real relation between True Mid Lat Sailing, and also point out the errors of Marcator's Sailing in which the geographical miles are used and Parallel Sailing assumed by spherical earth.