What makes an accurate GNSS timing receiver?
Six traits, in the order they start to matter. The last one separates a box that wants to be your master clock from a box that knows you already have a better one.
Tagged “oscillators”
4 pages · all tags
Topics In Timekeeping
How does GNSS holdover work?
When GNSS goes away your clock coasts on the frequency it was last told. How far it drifts is decided by your room more than your oscillator — which is why a holdover measurement and a holdover specification are different objects, and only one of them is a promise.
Accurately measuring elapsed time
A clock so bad the internet refuses to talk to it still measures a microsecond-scale interval to about a nanosecond. Short durations forgive both ways a clock can be wrong, and knowing when you are measuring one saves real money.
The limits of averaging
Averaging buys you improvement that stops. What is left when it stops is bias — and the same story plays out in position, in time, and in frequency.