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Comment by emilfihlman | Hacker News Reader

No. Dead reckoning is using relative measurements. Your algorithm is irrelevant.

Yes, but those "relative measurements" are IMU measurements, which are accelerations and angular rates. The only way to get position and attitude from that is to integrate. All that is to say, the parent comment was dead (sorry) on.

You’re being needlessly narrow minded. Any improvement on that integration that doesn’t use an absolute source of position is still dead reckoning. Do you think ancient sailors used IMUs?

He's not totally wrong here. The "IMU" you're using consists of a fix, clock, compass, and airspeed indicator (in my case). You're doing the same basic stuff that inertial guidance would do but slower and with less accuracy.

And going back to the great-great-great grandparent comment, I've heard from instructors and other pilots that the 'dead' bit of the word came originally from a shortening of 'deduced'. Something like 'deduced' -> 'ded' -> 'dead' or so. I'm not totally sure of the accuracy of that etymology but it sounds plausible to me.

Wikipedia disagrees:

The term "dead reckoning" was not originally used to abbreviate "deduced reckoning," nor is it a misspelling of the term "ded reckoning."

https://en.wikipedia.org/wiki/Dead_reckoning

I agree that without absolute measurement, it’s still just dead reckoning. However, the article is dedicated to describing a novel source of absolute measurement.

Do you... know what these words mean? Absolute positioning has to be calculated from an absolute frame, like GPS. This is relative positioning, corrected by detecting periods when there should be no motion.

Am I an old man now? Where is my cane? Get off my lawn!

Maybe, but I (selfishly) believe old dogs can learn new tricks. Leaving off the first sentence of your comment would convey the same meaning while keeping any well-earned crotchetiness hidden from view.

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