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Estimated Position Many navigators use the convention that a DR position takes into account only the recorded log (or speed and time) and course entries in the log book, with no other corrections. In these cases, if you correct the DR position for, say, current and leeway or either one alone, then the position you end up with is then called an Estimated Position. Other navigators simply think of their DR position as their best guess of their position taking all into account, which is the original definition of DR position.. If you see the term Estimated Position in use, the implication is that the position has been corrected for current, leeway, helm bias, instrument error, etc. In short, your best estimate of your position taking into account all you know that might influence it. CAUTION! Some textbooks use the term "estimated position" (EP) in a very special way. They call the point on an LOP that is closest to the DR position the Estimated Position. This is at best wishful thinking. There is no practical significance to the point on the LOP that is closest to the DR at the corresponding time of the LOP. Even if you consider the DR to be the EP as we propose above, this last step is not justified. Use of this concept could lead you astray. When you obtain an LOP by some means of piloting you have by definition found a line that you are located on, within the errors involved. Your DR position at that time will either be on that line or it will be off of the line. If it is off of the line, then you know your DR is wrong by at least the amount it is off of the LOP. If it is on the line, you know your DR might be right. Period. These are the only things you know. See also Tricky Terms in Navigation.

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