You could do something like that with an InReach device and it's satellite messaging functionality. Have a script (or person) expecte hourly preset message from

You could do something like that with an InReach device and it's satellite messaging functionality. Have a script (or person) expecte hourly preset message from you (it can send emails, sms, and even Facebook or Twitter messages) You could also use the tracking functionality as a double check that they didn't just forget to send the message by looking if their speed has changed inexplicably during recent intervals. It's not as ideal as it does ultimately require a human to raise the alarm.