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Elspode · 11-05-2003, 12:14 PM

If you are able to receive a WAAS-enabled satellite (or even both of them which are so equipped), you can get accuracy down to 3 meters, which I can get under good conditions. Is that accurate enough?

Real world use, without a lot tree cover, tall buildings or hills around you is 10-20 meters...still pretty damn good. Higher-end units apparently do 'averaging' automatically, and give you a distilled location based on multiple readings. The essential function of GPS *is* triangulation, anyway...triangulation with the GPS satellites as the basis. You need three satellites minimum to give you your location in three dimensions...long, lat and elevation. In fact, you don't get a reading at all on my unit without three satellites. The more satellites you receive well, the higher your accuracy. I've read tales of other users getting a zero error reading if they put the unit down and leave it for a bit.

I have a freeware program I downloaded called USA Photomap that lets you upload your GPS tracks and superimpose them over the Terraserver aerial photos/topos of whatever area you designate. I've got most of the KC metro area downloaded and in the program now, and it is spot on. I'll .jpg one of the tracks later on and upload it for you to look at.

This is cool, cool shit, man.

11-05-2003, 12:14 PM	#6
Elspode When Do I Get Virtual Unreality? Join Date: Dec 2002 Location: Raytown, Missouri Posts: 12,719	If you are able to receive a WAAS-enabled satellite (or even both of them which are so equipped), you can get accuracy down to 3 meters, which I can get under good conditions. Is that accurate enough? Real world use, without a lot tree cover, tall buildings or hills around you is 10-20 meters...still pretty damn good. Higher-end units apparently do 'averaging' automatically, and give you a distilled location based on multiple readings. The essential function of GPS is triangulation, anyway...triangulation with the GPS satellites as the basis. You need three satellites minimum to give you your location in three dimensions...long, lat and elevation. In fact, you don't get a reading at all on my unit without three satellites. The more satellites you receive well, the higher your accuracy. I've read tales of other users getting a zero error reading if they put the unit down and leave it for a bit. I have a freeware program I downloaded called USA Photomap that lets you upload your GPS tracks and superimpose them over the Terraserver aerial photos/topos of whatever area you designate. I've got most of the KC metro area downloaded and in the program now, and it is spot on. I'll .jpg one of the tracks later on and upload it for you to look at. This is cool, cool shit, man. __________________ "To those of you who are wearing ties, I think my dad would appreciate it if you took them off." - Robert Moog Last edited by Elspode; 11-05-2003 at 12:17 PM.