Check out the work of Andrew Back, which goes through the stages of just such a project.
Perfect for when you need to ascertain the location of equipment which is on the move and with systems that require accurate time synchronisation. The Adafruit Ultimate GPS HAT makes it trivial to add GPS capabilities to the Raspberry Pi, with the bonus of also integrating a real-time clock with battery backup, plus prototyping area.
In this example, we’re housing a Raspberry Pi 3 Model B (896-8660) plus Adafruit Ultimate GPS HAT (124-5481) in a DIN rail enclosure from Phoenix Contact (122-4298), although they could easily be housed in any one of a number of other enclosures with sufficient space to accommodate the Pi + HAT.
In addition to assembly and O/S configuration instructions, Andrew talks about gpsd and how to install this service daemon, then looks at the pps (pulse per second) signal and provides details of how to access it.
He then discusses creating an NTP server, providing tips and information on configuration. As part of the tour he also provides all the code necessary to test and implement the Ultimate GPS Hat.