View source for GPS clock

There are two separate yet related goals here:
* Create a local timeserver for my network, based on a GPS time-source on a raspberry-pi.
** Should use a 1PPS capable GPS module.
** Doesn't really need a display, though it can have one.
** Wired networking is fine
** I think it can almost entirely be based on existing packages, like gpsd, ntpd, etc.
* Create a standalone clock, using a GPS source, based on a raspberry-pi
** GPS can be a simple cheap, available one.
** Doesn't really need super-accurate inter-second timing, we're only going to display
   to the nearest second anyway.
** Absolutely needs a display of some sort
** Should be able to work with no network at all.  If wireless is available, to do FW updates or something, bonus.
** Power usage is somewhat of a concern, though could start out using wall-wart power
** A big 5" or 7" touch display is way overkill, but could display sun location, etc, and use touch for setup
** Use GPS co-ords to pick local timezone.
** OLED screen and batteries?
** Could we get away with solar power?
** low-power mode is a goal to get us off the plug
** any way we can have it turn the display off when its not light out?  or when I'm not looking at it? :)

==Things to Display==
* Date & Time in several formats:
** UT1
** UTC
** Unix
** Local
** MST
** AST
* Number of satellites used in fix
* Battery power left
* Day of week (text) and month of year (text) and week of year (numeric, ISO)
* Time to sunset/since sunrise
* Temp/humidity/pressure
* latitude/longitude
* local time-zone
* DST active

==Things to Adjust==
* Ideally nothing, other than date/time display preferences:
** 12-hour/24-hour?
** ISO formatting options?
** which time choices (above) to display at all times
* Other localization settings & options
** C/F for temp
** Power-saving settings?
* Some way to initiate FW updates?
** Would be cool if it would detect when my phone is making Wifi available, then:
*** connect to that
*** check git for FW updates (or somewhere)
*** check somewhere for OS and kernel updates
*** update itself if needed
*** reboot/restart app if needed

==Anything else to make available?==
* Maybe a calculator?  phone or laptop is more convenient, probably
* Some sort of calendar mode?  Again, for something like this, more than a glance, phone/laptop more convenient
* Something else I could see at a glance?  Home status?