[time-nuts] GPS accuracy specs

[Jimmy D. Burrell]

I've looked at several different manufacturer GPS datasheets now regarding the 1 PPS output in an attempt to compare apples to apples. Some of them rate their 1 PPS output as something on the order of "PPS signals have an accuracy ranging 10ns" which seems ambiguous. Does that mean the leading edge of their 1PPS is within 10ns of the GPS clock? Or simply that the stability of their 1 PPS is within 10ns? Or both?

Perhaps there's an industry standard for these specs of which I'm unaware?

The datasheet for my (presumably much older) Globalsat ER-102 seems, to me at least, to be much more clear stating "time reference at the pulse leading edge aligned to GPS sec., +/- 1 us". Which I interpret as the leading edge of my receiver's 1PPS is aligned with the GPS's clock to within +/- 1 us.

Jim...
N5SPE