I guess this is a dumb question, but I gotta ax it...
When navigating to a point with gps, i usually give it a zero elevation (unless it has a pre-determined elevation), when it's probably around, say, 600'. The question is, would there be a horizontal error associated with navigating to this point? Should I give it an elevation closer to what it really is? Or, if there is some horizontal error, is it significant enough to matter?
I would rather ax dumb questions than give dumb answers.
thanks,
terry

OK, you are navigating to points, which you have calculated.

IF your GPS system is 'localized' on an elevation that is similar, I would not think it would be much.

600' elev diff, should not introduce alot. Less than a hunnerth, methinks.

But now you have got me to wondering!

Thanks


N

BEFORE SELECTIVE SERVICE WAS TURNED OFF, I used to actually use the elevation as my benchmark.

I found that when the elevation was reported as closer, the coordinates were also closer.

When you introduce an elevation the reduction software assumes that you are at that elevation relative to the reference ellipsoid it is using (probably GRS80) and holds that elevation fixed while it solves for the other two ellipsoidal coordinatea, latitude and longitude.

You will get better horizontal coordinates if you input as good a value as you have for ellipsoid height (ie height above sea level plus geoid height).