hacking is

[unixronin]

A while back, Microsoft dumped a whole lot of outdated DeLorme mapping packages via Amazon for something like $15 each.

Well, sure.  The MAPS go out of date.  But the included GPS receiver doesn't, and the entire principle of GPS relies on having incredibly accurate time sources.  This time source information is available both in the GPS NMEA data

Comments

[unixronin]

If I'm correctly identifying which marking is the model number (which I'm fairly sure I am), it's a Pharos X13-51914. Works fine with ntpd v4.2.6 using the XType for "Generic NMEA GPS Receiver" at 127.127.20.0.