Most accurate GPS ?

steeltraps

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Joined
Dec 13, 2013
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247
Location
alabama
Ok If someone was burying something in the ground. Lets say treasure. And need to mark that spot down to the inch. What would be the best GPS system for that ? Needs to be accurate
 
After you bury it send me the coordinates and i will test my Garmin on it. If you find an empty hole then buy a Garmin Dakota!
 
A Trimble survey unit w/radio transmitter in a set location will do better than an inch but will set you back around $60-75K. The government puts in a random changing error into civilian units,
 
As I understand it the government imposed random (SA = selective availability) was turned off in 2000. Now the errors come in from atmospheric effects on signal travel time, number of satellites, signal loss due to obstructions, etc.
I Geocache in heavy terrain so the accuracy of my Garmin gets tested a lot. Using GPS, GLONAAS, and WAAS my typical repeatable accuracy is 8 ft in fairly thick cover, 16 ft in horrible cover, and 3 to 4 ft in open area assuming I let the GPS waypoint average for at least 5 minutes regardless of "%complete" it states.
'Survey units running RTK (like Trimble) where base unit waypoint averages all day and sends the mobile unit time correction signals easily get down to less than an inch.
'For reference when working with a surveyor friend of mine running a RTK setup we have found Google Earth maps to be 20 ft or more off when referencing to an obvious physical point (tree, fence post, etc). For that reason I never use Google Earth as my final method of determining coordinates if the measurement is critical.
 
I am a land surveyor and did a test between my survey GPS and a Garmin Etrex 20. Difference of 3m was found. The Etrex was not left measuring for long and there were no obstructions close by. To navigate back to a fixed point with 3m accuracy is foolproof. Take into consideration that the Etrex resolution is 1m.
 
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