I note that the GNSS support in Release 43 includes an extra digit for tenths of seconds. Is this workable as a better UTC time source than the present scheme of 1 sec resolution for time() on the device?
I confess I haven’t tried it, but the documentation gnss-session.readposition() | Dev Center suggests that you get hhmmss.sss – that is, milliseconds.
This is likely to be a far better measure of UTC than time() from the onboard RTC; GPS time in general is accurate to tens of nanoseconds absolute difference from UTC, so the millisecond precision reported is not spurious.
Ahem, having seen some real output now, the documentation says you get milliseconds but in fact you might indeed just get deciseconds. Still way better than time() though.