I wonder why people aren't more aware of personal locator beacons that use satellites to work in areas without cell reception. For the cost of a smartphone, this could have saved her life :(
This won't work really the towers have to be fixed making a call while moving shifts the phase of your signal and for a good while this was a big problem for early phones (calls out cut out while driving or in a train because of the speed not the "reception").
Movement is not the only thing that can cause a Doppler shift, echos, and multi-path propagation are also a pain to deal with but for the movement part phones pretty damn early started having accelerometers (way before they were used for cool stuff) in them as well as much better Doppler estimation processing at both the towers and in your phone.
At 150knots (relative speed, this will depend on the altitude and heading of the aircraft in relation to the cellphone) a 1.9ghz signal will have a Doppler shift of about 500hz which is more than enough to induce blocking of pretty much any cell network.
Radiophones that allow air to ground communication to exist but they are designed for this purpose and implement quite aggressive Doppler correction which is also usually only possible when they have the flight data and they know more or less the altitude, heading, and speed of the aircraft based on the flight plan and real time flight data and can adjust the Doppler correction in real time, as without it it won't work.
Meanwhile the FBI is supposedly flying over cities sniffing cell phones. It might not be easy to establish a voice connection, it seems pretty likely that it will be possible to detect the phone if it is broadcasting at all.
Yes because it's using a military grade sigint platform.
Capturing signals and reconstructing them isn't hard when you fly special mission aircraft.
But you can't just strap a picocell to a SAR aircraft and expect it to work.
Also cellphones don't have that much of a battery life if a hicker has one its most likely going to be either off due to them being out of coverage or dead due to battery drain by the time anyone figures out they are missing.
Considering the cost of such platform and the little to no use it will bring the money is probably better invested in high resolution FLIR cameras and more aircraft since anything that could ping a phone and get its location would cost more than a civilian SAR aircraft.
I'm not aware of a similar thing in the US. And depending on the remoteness of your location, you may get an indication of a good signal (3+ bars) but still be unable to transmit or receive a text. It's common in the mountains where I hike and backpack to get "ghost bars" like that which suggest you should be able to send and receive messages but only a tiny percentage ever get through, if any.
The US has actually several emergency networks, a cellphone even without a valid sim card can still be used to dial 911 this is part of every cellular standard.
But in more common cases when you are outside of the coverage of your carrier and with roaming disabled/no roaming partners you will still see Emergency/SOS displayed on your phone.
Besides 911 there are probably a few other emergency numbers in the US which are open on all cellphones, as well as the emergency broadcast system which will display push notifications on every modern cellphone in such cases as natural disasters.
They're growing in popularity, but they're expensive and some of the popular ones (not PLBs specifically, but satellite trackers & communicators) like SPOT and DeLorme inReach have monthly subscription fees as well. Someone who isn't out alone all the time may not feel they can justify the cost.
I carry an inReach and find it fantastic. I've never used it for an emergency (though an emergency leading to a late-night Air Force helicopter rescue of someone in my hiking group several years ago prompted me to purchase it) but it's fantastically useful for text communication with friends and family in areas with zero cell reception, as well as (very recently added) weather forecast downloads for your precise location. And in the event of an emergency, being able to communicate details about your situation is very useful sometimes.
You can also rent a PLB/sat communicator for relatively reasonable prices (<$40/week) if you only hike occasionally and owning one and paying monthly wouldn't make sense.
I've done a bit of backpacking (with a 3 week trip planned this August), and I would certainly take one of those if I were hiking alone. It sounds like this woman started with a partner and ended up continuing alone after the partner had to abort.
Would be great to be able to pair this with a small solar charger.
Also, do these work internationally? I went scuba diving in Indonesia in a place with strong currents. Saw amazing creatures, but there was a story overhanging everything about some divers that had been swept away by currents, landed on an island inhabited with Komodo dragons & had to fend the lizards off by swinging their weight belts at them. They were found a couple days later, but badly sunburned and exhausted. Amazing!
My DeLorme inReach can send a message with coordinates and then doesn't need to remain online and continue transmitting. (Of course, you want to keep it online so you can continue to communicate with SAR, but if the battery were to die they would still find you as long as you don't move from your transmitted location in your emergency call.) So a solar charger, etc. wouldn't even really be necessary, and it will stay online for quite a long time between recharges.
Many long distance backpackers will carry high capacity USB battery packs to recharge devices off rather than a solar charger, as they weigh less and involve less hassle and can generally last between town stops every 5 to 10 days (depending on what trail, of course).
I'm not familiar with all PLBs/satellite communicators but my inReach works internationally.
https://www.rei.com/learn/expert-advice/personal-locator-bea...