[time-nuts] Trimble T-Bolt Dumb Question

M. Warner Losh imp at bsdimp.com
Tue Jul 8 15:39:36 EDT 2008


In message: <20034192.1215543624602.JavaMail.root at mswamui-backed.atl.sa.earthlink.net>
            "Richard W. Solomon" <w1ksz at earthlink.net> writes:
: How does one determine that they are "locked" to the GPS system ?
: If I look at TboltMon I see lots of data, but nowhere do I find a
: specific statement that I am locked.
: 
: The output frequency is accurate and stable enough to be locked and
: I see I have anywhere from 5 to 8 satellites tracked, but ....

Usually "locked to a GPS system" just means that the oscillator that's
controlled by the GPS is operating within some set of prescribed
parameters and that the GPS receiver itself is a 'good enough' source
of time.  The exact definition of good enough varies quite a bit from
system to system.  You basically have to look at the numbers from your
control loop, as well as self diagnostics from the GPS receiver to
know if there's a lock or not.

Warner



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