On 2014-08-07 15:46:30 +0000, Ramy said:

Even with 8m accuracy, It is more than sufficient for accurate
collision avoidance, unless someone considers half a wingspan not
accurate enough for collision warning with another glider or obstacle.

Even the old 100m accuracy when "selective availability" was turned on
was good enough for avoiding antennas or wires etc. It's not as if you
are going to fly as close as you can to them.

Also, note that the errors are not random. Two GPS receivers in the
same area at the same time will show the same error, in the same
direction (to within 6 or 8 m), thus making their relative locations
accurate enough.