Which segment does NTPD use? Does it use both segments to determine/set the time? I was not aware that there are two ways that the time can be set. Thanks for passing that information on. My best guess is that it would be SHMO(0). I don't think we have access to PPS from the device.
What I am thinking about doing is leveraging our existing implementation that configures the device and reads the messages and add to it the ability to forward all messages to another tty (i.e. /dev/gps0). Then start gpsd up using this tty. I prototyped something along these lines to test it out but I didn't see anything when I ran ntpshmmon and the time was not getting set. I did see that gpsd was reading messages correctly using the gpspipe tool.
I know this is probably a convoluted way to do this but time and money do not allow us to do more. In our next release I plan to go full gpsd.
Thank you,
Joe B.