CONS 127 Lecture Notes - Lecture 3: Nautical Almanac, Nautical Mile, Marine Chronometer
15 Sep 2017
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Document Summary
Absolute position: geo-positioning or positioning is the identification of. Distances trilateration: the base angles at a and b can be measured with an instrument called a theodolite. By knowing the base distance a to b, and the angles the distance to the peak can be worked out using triangulation: measuring angles, theodolite. Great britain, and large parts of europe: the geodetic points are the basis for the mapping of the. Ocean navigation: no permanent markers on the ocean, navigation methods using, relative positioning, pilotage. Navigation, within sight of land: based on visual triangulation to known landmarks, no need for accurate position, but that one is in a safe position or on a safe line, generally helped by maps or nautical charts. Requires very precise information on speed and direction over long distances -> cumulative errors: dropped something off the ship to determine speed of boat. Earth motion 24 h: latitude calculation.
