Dead reckoning

Dead reckoning is the most basic form of navigation. Someone who a) knows where they were at some time past, and b) knows the path and velocity they are traveling, can calculate where they are now. Or will be, at some point in the future. There are a few problems with DR. First, it takes constant vigilance. The navigator who fails to account for a change in course or speed when it is made has to guess what the path was. Second, one may have only rough measures of those, especially when current is involved. Third and most importantly, all those errors accumulate. The circle of uncertainty gets ever larger. Which is why the navigator needs periodic fixes by other means.

A smartphone that could do accurate DR over long distances would be a wondrous thing. One might ask why that is important when GPS now provides a constant fix? Because it is a poor navigator who relies on only one method to find where they are. I trust when this hardware makes its way into digital devices, Garmin software will make smare use of it.

The cellphone is today’s necessary piece of tech. Especially for those on the move. Even without cellular service, it is one’s set of maps, library, pencil, note pad, calculator, post office, and navigation, all rolled into one.

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