If my memory serves, commercial and military GPS units have a high degree of difference in their accuracy.
I wonder which they’re using...
Military, I’m sure. Accuracy is within inches.
But, why bother with all of the manual work? There are already plats, deeds, title records etc., plus plenty of high res satellite photos. This is taking accuracy to a ridiculous level. I wonder what other data they're correlating to the GPS point?
Not anymore. Military units simply had access to the encrypted signal, which was more precise. The unencrypted signal had random variability introduced into it -- the euphemism was "Selective Availability".
However, Clinton signed an executive order to turn off Selective Availability, so civilian units now have the same accuracy. I believe the DoD has the means to reinstitute Selective Availability very quickly if necessary.
Not any more, several years ago the accuracy restraints were lifted. They are used to survey, grade roads, etc, now accurate to within a fraction of an inch
Only if Selective Availability is turn ON. I don't believe it is now. I know that it was turned off in 2000 in part because so many military units, down to squads, were using commerical hand held GPS units. In fact a picture taken from a British helicopter of the Iranians grabbing one of their ships, had a GPS unit in the photo identical to mine, documenting the position of the ship at the time. (It was in international waters, but close to Iranian waters)
I used commercial GPS (for a federal job) in the 90’s when there was a 100m longitudinal and a 156m latitudinal scramble. The units that these people are using are not that bad, but tend to wobble and wander a good bit.
They are not counting doors. Not all who work for them are convinced it is good to be too precise, either.
Don’t want a visit - live behind a locked gate that looks like it goes nowhere. if you can’t do that, put up beware of dog signs, many worker bees will guess rather than take a chance.