"Most cell phones have GPS .. that would get a 10 meter radius, not 3 km"
The 3km refers to the distance at which a phone call can be made between hiker to helicopter/plane/vehicle - once the call is connected, you can tell them exactly where you are (or at least as best as you know), with detailed information like injuries, present threats, number in party etc.
I have recently purchased an Ulefone Armor 23 which has satellite connectivity built in - unfortunately the service provider, Bullitt (
https://bullitt.com/en-gb/) is not yet operational in Australia, but has announced connectivity in 2024. It uses Inmarsat and Echostar satellites which are geostationary, rather than Low Earth Orbit sats used by Apple. Plans are relatively cheap (at least they are in the North America and Europe), with 10 Euros a month for SOS and 80 text messages in and out. As I am currently unable to use it, I can give no recommendations or insights, but I'm hoping I will be able to try it before the end of the year. There will probably be many other services like this entering the market in the near future.
Skibug