Your cell phone could save you even when you have no service

[sprengers4jc]

Pretty fascinating stuff! As an experiment, I checked mine and saw it was mostly accurate and then I checked my wife's and there was virtually no data. Then I remembered that she rarely turns on her GPS signal but I knew we used it for nav on Saturday so I checked that day and sure enough, there was our route. When I record hikes in BCN, I always have the phone in airplane mode to conserve battery so I picked our last backpacking trip through Cottonwood Canyon state park and voila, here it is, complete with our route home...

So it seems as though one must (obviously) have GPS turned on, and have interconnectivity through Android and corresponding Google apps, etc. And yes, it actually could, in theory, replace a Spot except for the sending of messages stating that one is in trouble. Great stuff, guys. Thanks!

[sprengers4jc]

I will also say that when my wife had a seizure and fell off the EC trail 2.5 years ago, I had no cell signal from that canyon to call for help. My phone had been on the entire time, and was not a smart phone at the time. Desperate, I dialed 911 and got the message on my screen that there was no service. Then, I kid you not, I actually did this....

And had full signal and called 911 on speakerphone and spoke to the operator for at least 10 minutes and never got cut off. Maybe just the attempt to call 911 also triggered something? Never have been sure what exactly happened that day but no one else we encountered on the trail had service, either. We were just grateful we got through.

[Koda]

That's a good way to test it! I don't generally put it in airplane mode when I'm in "civilization," but I'll try to remember doing it before going on a lunch walk, and see what it shows when I get back to the office!

I dont think you need to have it in airplane mode to test its upload frequency....

So it seems as though one must (obviously) have GPS turned on, and have interconnectivity through Android and corresponding Google apps, etc.

as far as I know you only need to have your "location services" turned on, you dont need to specifically turn on a GPS app. Im not certain how any of that affects upload frequency for realtime viewing. I know that when I've checked mine I didnt have any GPS apps running on my commute.

----


So im not certain how much of a thread drift this Google tracking is, its related certainly but Im still curious how leaving our phones on wasting battery when you dont have a signal can help SAR reach you. Im skeptical.

[Lurch]

Oi, this could turn into a long and technical conversation.

Most 911 systems were established in the time before cellphones, when landlines were the only options and they *knew* the address/location for every phone out there. That was all fine and dandy, they could trace things back and pull location data quickly and easily. Now it's not the case anymore, and the 911 centers are struggling to keep up with technology. They have so many standards to follow, and different systems they need to mesh with it isn't an easy task at all.

That, coupled with nearly every cell carrier handling their 911 functionality slightly differently makes it even more difficult. The initial bid's on a cellular 911 aren't always (usually) accurate. Some will pull GPS data before a solid lock (if you're talking with 911 ask them to "rebid" your phone after about a minute and they should get more accurate coordinates). Others triangulate off cell towers, and if you aren't hitting enough towers they won't get much of anything, and we may end up with coordinates for the tower itself, not you. Luckily we spot those ones easily enough

Most 911 centers don't accept SMS, although some do. It takes less power, and less signal to get a text message through than voice, so you *can* attempt to send a txt to someone, and let your phone idle. If/when it gets service it will attempt to push it through (depending on the phone, some will force you to tell it to attempt again if it fails). That will use less battery than attempting to call, and will attempt to force those 'handshakes' which can indeed be tracked later if need be.

There are some well established systems for Law Enforcement in emergency situations to gain that data, lost persons fit that qualification, although it's much easier if there is a spouse or someone else on the account that can grant permissions. Some carriers don't hold historical data, and will only give the last ping. Some don't hold location data and will only tell what towers were hit (potentially what antenna on what tower). This can help narrow things down... but often times it's still a massive search area. Tie ALL that in with the fact that a lot of our wilderness areas skirt county lines (who is responsible for SAR) and if you hit a 911 center there's a very good likelihood it will be in the wrong county, or even the wrong state.

I will say cell pings have gotten better and better through the years, but I wouldn't rely on that for much of anything.

• Most definitely learn how to pull coordinates on your phone.
• Turn it off until you need it, or at the very least keep it in airplane mode
• Keep the phone dry (obviously) and warm. Cold batteries don't like to give up their power easily, and will effectively "die" quicker.
• If your battery is dying, and you're in a place with service:
  1. Do NOT waste battery calling family/friends/flashlight/taking pictures etc, save that precious juice for SAR
  2. Establish a schedule with the coordinator if needed. ie Phone is OFF and inside you jacket, you turn it on for 10 minutes on the hour, then it's back off and in the pocket. If updates are needed they will happen then

Remember, a GPS whether in your phone or another handheld unit is just a receiver, it's purely listening and doing calculations, which is why it works in airplane mode. Even if your *phone* has a log of where you are, you don't necessarily have a way of getting that information to the people that are looking for you.

A text or a screen shot of coordinates can go a long ways when there are spotty voice coms, Most all phones are going to be working in WGS84, so you give me coordinates in just about any format and I'll get them plotted

[Lurch]

when-your-phone-has-no-signal.jpg

And had full signal and called 911 on speakerphone and spoke to the operator for at least 10 minutes and never got cut off. Maybe just the attempt to call 911 also triggered something? Never have been sure what exactly happened that day but no one else we encountered on the trail had service, either. We were just grateful we got through.

You cell is basically a fancy radio, working on a relatively weak signal, and *you* are essentially a giant bag of water blocking a large chunk of its field of view. You'd be *amazed* how much simply holding it up, and getting it away from your body can help.. I've heard of people tying their phone to a stick, and using a bluetooth earpiece to hold their phone up 10' for a signal and call for help.

[kepPNW]

That's a good way to test it! I don't generally put it in airplane mode when I'm in "civilization," but I'll try to remember doing it before going on a lunch walk, and see what it shows when I get back to the office!

I dont think you need to have it in airplane mode to test its upload frequency....

Okay, well, this has a very simple answer. No location data is uploaded to Google when airplane mode is turned on. It's easy to test. I just put on airplane mode, went for a 3 mile walk, and when I got back (even after waiting nearly an hour), no location data for my walk showed up. Try it! You'll see. Wish it weren't so, but it really sounded magical if it worked any other way.

So it seems as though one must (obviously) have GPS turned on, and have interconnectivity through Android and corresponding Google apps, etc.

as far as I know you only need to have your "location services" turned on, you dont need to specifically turn on a GPS app. Im not certain how any of that affects upload frequency for realtime viewing. I know that when I've checked mine I didnt have any GPS apps running on my commute.

Once you're outside the range of normal cell towers (like in the middle of Indian Heaven or Jefferson Park), the only way they'd be able to get that location is with the GPS receiver.

Oi, this could turn into a long and technical conversation.

Truly appreciate your insights, Lurch, thanks!

[Koda]

No location data is uploaded to Google when airplane mode is turned on.

I will have to double check this when I have time. Last time I looked at this I viewed a track from an off trail trip I did last summer into a canyon with no cell service. I was in airplane mode but I did have BCN running so that means I turned on my GPS reciever. I will have to double check all this when I have time. maybe there is a delay on saved tracks that get uploaded at a later time... IDK.

[Lurch]

Koda: I would suspect that your GPS was keeping a log, and it was uploaded after the fact. There's a number of apps out there that will give you access to your GPS data, regardless of your connection with a tower.

Assisted GPS (A-GPS) gets a boost by using tower data to help determine it's location.. That assistance could come in one of two forms, 1: Providing GPS almanac data and time so you get a faster lock, and/or 2: Using remote computing power and data to help crunch the numbers and give you a more accurate fix. If you're outside of tower range, than your phone is going to act independently, be a bit slower, and possibly less accurate, but still function. This is how people log GPS tracks of their flights when they're hopping on commercial airplanes

Obviously it would be way more helpful if friends/family had access to accounts and could pull remote data, unfortunately that doesn't always work.. If it's you reporting yourself lost it's a lot easier, or if there are exigent circumstances the argument can be made to request data without a court order. The James Kim search a few years ago did a lot to push those pathways open.

So... the question is, if you have a smart phone, is everyone here capable of finding your coordinates with it?

[kepPNW]

So... the question is, if you have a smart phone, is everyone here capable of finding your coordinates with it?

Sadly, it's hit/miss. Deep in a forested canyon in crappy weather, no. Signal acquisition with a smartphone [admittedly, a few years old] simply doesn't begin to compare to that with a dedicated GPS. Which is why I carry both.

[Lurch]

Most definitely!

I think my thought process was more along the lines of, if you had to communicate your location to someone else would you be able to? or do you use your GPS only for tracking and haven't learned how to use proper coordinate systems?