>>1048517>>1048607this guy is correct gps is basicly a time stamped signal with a satellite name.
after u get you signals it's simple math for triangulation. absolutely no difference between a modern phone and handheld gps in precision. the handheld might have a better decibel antenna ( you might get better reception in bad conditions like a closed canopy above) but the the phone might have a-gps data from the internet before you left the reception area.
this is a one way communication.
what you need is a satellite phone/ device running on iridium ( the service not the element) or any other service.
there are cheaper pagers or rentals. you can also buy land locked stuff cheaper. like only africa, but nothing else. last time i saw one was in extrem sport trip in nepal as a safeguard it was 1$ per minute and bit less for sms. 30 day rental ~100$ with 10 min/messages included. IIRC
