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I think it's great for phones to include to have some of the functionality of a SEND (Satellite Emergency Notification Device) front-country situations where ce
by almog 4y ago
I think it's great for phones to include to have some of the functionality of a SEND (Satellite Emergency Notification Device) front-country situations where cell service is unavailable. These are some of the reasons why I wouldn't use it as a replacement for an ad-hoc SEND or PLB (which I use for long distance hiking):
1. Short wave length (~2.4GHz iPhone < 1.6GHz SEND < 406MHz PLB). Shorter wave length are less affected from terrain obstructions.
2. UX - to send an emergency signal using iPhone, due to its shorter wave length, one has to point to the approximate LEO satellite position. Last time I searched on how it would look, it seemed that an on-screen instruction would guide the user where to point the phone, I'm not sure if there there is any accessibility mode that would use voice to do that if for example the screen is broken (or the user cannot see).
If the screen is broken, would the user even be able to activate the SOS feature? Using voice? What if you're caught in a super noisy wind storm or the mic is broken?
Perhaps future models will have a physical trigger to activate it.
2. Durability - other than PLB/SEND being much more durable when it comes to impact and water damage, the battery itself, at least with PLB is rated up to -40. A phone battery starts to become unreliable at +30f.
3. Latency and reliability: iPhone I believe, due to its short wavelength only transmit to LEO satellite, where as PLBs does LEO, GEO and MEO, which means lower latency in some cases, especially when the sky is obstructed by terrain and even more so if you're unlucky to be in an east-west canyon that doesn't follow a LEO satellite orbit, theoretically at least you have a better chance with GEO satellite. Also, in places such as canyons where GPS fix is unreliable, COSPAS-SARSAT MEO and LEO satellite that serve PLBs will use Doppler location approximation. Not sure if Iridium LEO satellite that serve iPhone do that.