Garmin has two features along these lines:

• Live Track is real time location sharing. It's the one that's most like Beacon. People say it's flakey.
• Incident Detection sends out a "help me I crashed!" text to your contacts.

If incident detection works, it's a much better option. I got hit by a car years ago while my GF at the time had a live track for me, for that kind of reason. She found out when I called her on my way to the hospital. She wasn't just staring at the computer watching my progress. People don't really do that. So Live Track and Beacon is more like a body finder tool than a get help tool.