spot connect, spot messenger or similar "emergency" device. DeLorman (sp?) also has ones. We use ours all the time to send messages to kids, friends etc. to let them know where we are when out of cell range. In 5 years we have yet to not have a message go through, Uses sat. uplink and downlink to send messages to email addresses, smart phones etc.
Also can be used to send emergency help message to 911 or roadside assistance.
and of course we carry a good first aid kit, tools, food, water etc. to keep us safe.
And BTW, our kids know exactly where we are because they can access our location from our onstar android app. I've given them the password. so if we do need help, they would get a message from the spot with our exact gps coordinates along with being able to verify from onstar vehicle location.
If we are going to remote locations I turn on gps tracking on the spot's and the kids and/or friends can track where we are if needed to contact us.