@mcc https://www.gps.gov/applications/timing/ claims 100 nanosecond accuracy, other sources claim less. The 1.5s number isn't sourced, I suspect it's a particular*receivers* limit ? Each satellite might transmit in 6 second intervals but you normally have a fix on at least three.
@mcc Sure, but a precision that much smaller than resolution seems kind of overkill.
https://www.gps.gov/applications/timing/
" This enables users to determine the time to within 100 billionths of a second, without the cost of owning and operating atomic clocks. "
that's not just precision.
1.5 is apparently used in the time of week signal. Which is apparently separate..and yeah might work as the heartbeat signal
@mcc I found someone's thesis on Agps which breaks down the signal structure if you really wanted to dive down the rabbit hole..
https://scholar.colorado.edu/downloads/fx719m772