DeLorme in reach.
Has a companion app that works on Iphones and Android, relies on a separate stand alone tracker, this is all sattelite based.
Does not need nor use phone signals.
Costs 10 or 15 quid a month, tracks you at all times and allows anyone you want to find you in real time, at any time.
Will also upload your location to (if you want) a public website, you'll show up in real (ish) time with alt, spd, heading showing also.
It is possibly overkill, but I fly out in the boonies in Scotland and we have previous of it taking days to find people crashed in the hills.
You can also pull the SOS pin and have a nominal Mayday sent out, as long as it can see a sattelite, it should get out.
For me it bridges the gaps between being tracked on flightradar24 (Via Flarm) Mobile phone tracking (phone records can be accessed in an emergency to find your last mast check in and probably triangulated from there)
Scotland just has far too much area not served by Groundstations so I rely on a sat based service to find me if it all goes a bit pete tong.