My wife wants to know that when I do my John Muir Trail trek starting on 7/26/2016 I've not fallen down and can't get up, or been eaten by a bear...
So, I've been building my DIY "SpotMe" Iridium Network-based GPS-Satellite Comm device.
I've gotten to the basic level of communication; It reports my position on a regular basis (the following is from a morning conditioning hike).
To my surprise, when I set the deconstructed system up on my kitchen table, it managed to both get a GPS fix AND successfully transmit the data to an Iridium satellite. Given that there is really no "sky" visible