Do you have set the IP for supl.google.com to /etc/hosts? Pick any of these and set it to hosts file. https://www.whatsmydns.net/#A/supl.google.com
I have no idea what you are talking about (GPS EPOCH, rollover, Sygic stuff), but generally I think GPS should work (works for me, tested 2 days ago) if you have done the ip setting.