Here in "Gear Up!", there is a lengthy thread concerning reliance on GPS as a sole means of navigation, and of the wide variety of problems, many of them lethal, which can occur when traveling with no other navigation tools.
The discussion naturally morphed into the subject of EPIRBs, PLBs, and such. Good stuff.
I was reminded today of a satellite-based device and service known as SPOT. The SPOT allow for a wide variety of GPS lat/lon updates, emails and texts uploaded from a smart phone to the SPOT, and ultimately to one's target audience via satellite, and such. A 120 second scan of a SPOT website shows lots of purchase options with respect to the devices and to subscription plans for "air time".
I would enjoy learning of RTA members' experiences with any satellite-based communication/emergency location devices.