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My dedicated Garmin GPS (no supplementary GLONASS) unit has 3 meter accuracy.

As long as you have an unobstructed view of the equator. To get 2-4m accuracy with commercial GPS you must use WAAS. The sattelites that tansmit the WAAS signal are geostationary.

So if you have buildings, hills or mountains blocking your view you're back to 7-15m accuracy. It gets worse thr furer north you go as your angle to the WAAS sattelites gets closer to he ground.

Plus it's North America only. Not sure if Garmin units support EGNOS which is the system in Europe.

EGNOS and WAAS use the same frequencies and same protocol. They're essentially two implementations of the same thing. As far as a receiver is concerned, they are identical. My Garmin eTrex 20 receives both without issue.

Thanks, nice to know.

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