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Here are the Bowditch definitions with our [added notes.] See individual terms for more details

n. A point defined by stated or implied coordinates, particularly one on the surface of the earth.

A fix is considered an accurate position determined without reference to any former position.

A running fix is a position determined by crossing lines of position obtained at different times and advanced or retired to a common time.

An estimated position is determined from incomplete data or data of questionable accuracy. [this is fair enough generalization]

A dead reckoning position is determined by advancing a previous position for courses and distances. [ we use DR to mean apply every correction you know about, not just log and compass. this is the original definition of DR]

A most probable position is a position judged to be most accurate when an element of doubt exists as to the true position. It may be a fix, running fix, estimated position, or dead reckoning position depending upon the information upon which it is based. [this is tricky terminology. It is a statistical term that needs much more clarification. We use most likely position.

An assumed position is a point at which a craft is assumed to be located. [This is essentially wrong. The AP is part of a celestial sight reduction, with well defined meaning.]

A geographical position is that point on the earth at which a given celestial body is in the zenith at a specified time, or any position defined by means of its geographical coordinates.


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