Precision vs. accuracy of what measurement?

For GPS to work at all, you need very accurate knowledge of the offset between each satellite's signal.

The only way I can think of to have precision but not accuracy is if you design a system where there's a buffer between the antenna and the signal processing and you don't know how long the buffer is. Is a design like that a practical concern?

They're saying that as a receiver of GPS signals, it doesn't matter if your clock is out of sync with everyone else's clocks, as long as it measures the length of a nanosecond accurately.

But GPS gives you a clock signal.

Of UTC. Theoretically GPS can work out of sync with respect to UTC as long as all satellites are in sync among themselves.

Oh, you're talking about a theoretical situation where the GPS satellites are reprogrammed to use a different synchronization source? Personally I'd still call that highly accurate, but to a different time standard. But I see where you're coming from.