+Skip_ Posted May 8, 2004 Share Posted May 8, 2004 I'm just a little curious, how much effect does an incorrect elevation in a waypoint have on accuracy? Does it matter a little, a lot or not at all? Quote Link to comment
+New England n00b Posted May 8, 2004 Share Posted May 8, 2004 In regards to lat/lon accuracy, I don't think it has anything to do with it... It might, but I can't see how. Of course, I'm dead tired too, so maybe it's blazingly obvious. I'm sure a GPS guru around here will pipe in with an answer... Quote Link to comment
Kerry. Posted May 8, 2004 Share Posted May 8, 2004 (edited) With a 3D position solution (4 sats or more) the elevation is part of the solution so is relative. With a 2D solution (3 sats) the elevation has to be assumed or manually input and if assumed wrongly then it can equate to around 5 metres in position for 1 metre in height. About the only place where specific 2D solutions can be implemented with any reliability is on a boat but even then a 3D solution is generally going to be the preferred option. But as far as a "waypoint" is concerned, that is one previously stored with the height at the time then it has no affect on latter accuracy with respect that waypoint what so ever. Cheers, Kerry. Edited May 8, 2004 by Kerry. Quote Link to comment
+writer Posted May 8, 2004 Share Posted May 8, 2004 The elevation shown by GPS receivers is notoriously inaccurate, even if you do have a fix on four satellites that are nicely spread out to increase accuracy. In theory you should be within 75 feet of the actual elevation, but in practice it can be farther off. The problem is that GPS technology uses a theoretical model of the earth's surface. However, it shouldn't affect the position. Quote Link to comment
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