Today I looked up SPOT GPS trackers.  This could be used to communicate position to up to 10 family members.  It will send a text message or an email to let them know that you are ok.  Also, provides real time tracking on google maps.  The device has an emergency 911 feature included.  The only problem is you must have clear sky above for it to work.  Cost about $100. Yearly subscription tracking service another $100.  Battery life could also be a problem if it is always on.  My thinking is I may need this so my wife can keep up with me while hiking the AT.