Stratum one autonomy and assumptions about GPS

[Dan Drown]

Quoting "Eric S. Raymond" <esr at thyrsus.com>:
> Is the CPU temp going to be a good approximation of what the clock sees,
> though?  I can think of several reasons to doubt it.

It's better than nothing, but it does have two limitations:

1. the CPU heats itself at a different rate than the surrounding  
board, so it can be much hotter than the oscillator
2. the in-CPU temperature sensors tend to be low-ish resolution

For example, see the first two graphs:
https://blog.dan.drown.org/beaglebone-black-ntpgps-server-temperature-compensation/