(A shameless request to make my swell idea popular enough that Andrew Johnson, the creator of the excellent Gaia GPS* app, might incorporate it. Gaia GPS is a sweet little gps navigation app that is fast becoming my go-to "where the heck am I?" app.)

Folk who use an iPhone's GPS for navigation in the backcountry know there are many tricks to prolong battery life.

But unlike the AT&T version, the Verizon (CDMA) iPhone can't turn off the battery-hungry cell service without also disabling the GPS receiver. Why this is, I don't know, but it is and it sucks.

One workaround is to keep the phone off entirely, the boot it when a fix is needed. This takes a while.

Another is to put the iPhone into Airplane mode when it's not needed, to shut off the cell radio and the GPS receiver, then turn off Airplane mode when a fix is needed. Then go back and put the phone back into Airplane mode. Switching back and forth between Settings and Gaia GPS to do this is a lot of steps.

So I think that an Airplane Mode on/off button be built right into Gaia GPS, at least for the CDMA iPhones, and made a suggestion to that effect on their feedback/suggestions site.

If you use Gaia GPS and a Verizon iPhone, and think my idea is as nifty as I think it is, please pop over to https://gaiagps.uservoice.com/forums/118985-general/suggestions/2920510-give-verizon-iphone-users-a-way-to-turn-airplane-m and sign up (easy-peasy) and vote for idea.

(I also think a big ol' analog compass dial which gives bearing and distance to a target waypoint would be a good idea, esp. for those of us who need to put on glasses to read. Someone else already proposed that idea, I added my vote, maybe you might be in agreement: that link is at https://gaiagps.uservoice.com/forums/118985-general/suggestions/2896329-analog-compass-option)

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* http://www.gaiagps.com/ -- I am not associated with them other than being a user.

"But unlike the AT&T version, the Verizon (CDMA) iPhone can't turn off the battery-hungry cell service without also disabling the GPS receiver. Why this is, I don't know, but it is and it sucks."

Some cell phones have autonomous GPS receivers inside them, so they can operate much like a dedicated GPS receiver regardless of whether there is any cell phone service.

Other cell phones have "cellular GPS" which doesn't really use GPS satellites at all, and it simply performs sort of like GPS by triangulating its position based on signal time-of-arrival from different cell phone towers.

Others still use cellular-assisted GPS, and this uses the signals from cell phone towers to help push the GPS functions toward a quicker fix.

The bottom line is that different phones use different services to get different kinds of performance in different areas of the country. Don't expect them to all work the same way, especially as you get into the backcountry.

--B.G.--

Have you done any research on determining if you can "jailbreak" the iPhone to allow you to shut of cell signal while maintaining gps? Prior to release of MMS on the att iPhone, i did this and the apple os took over allowing the feature.... also, not wanting to give-up my grandfathered unlimited data plan, i used a jailbreak to allow for wireless internet tethering. Aside from opening up features disabled by the carrier. It is almost mindless to complete yourself (step by step instructions from redsn0w are very easy to follow). Also if you ever have a change of heart or warranty concern, you connect to iTunes, and click restore..... Also, various cell phone stores will jailbreak for you for around $15-50.00 and can most likely tell you in advance if jail breaking will allow you to use gps without searching for cell signal

Best of luck.... just an alternative I thought may be worthy of consideration.

... a cell signal is entirely unnecessary for the operation of the GPS function. I spent this week driving in areas where there was no service but the GPS continued to work just fine.

So the CDMA iPhone clearly does have a dedicated GPS receiver; perhaps it is integrated into the CDMA chip(set). It is a mystery to me why there isn't a software or hardware way to independently enable/disable the two services.

@Andrew Brown: can someone verify whether jailbreaking the Verizon CDMA iPhone allows one to shut off the cell phone radio w/o turning off the GPS receiver? I did think of this but hesitate to tinker with the phone as it is a corporate phone and not mine to break.

Jack. Have you read this?


http://adventurealan.com/iphone4gps.htm

... "Verizon iPhone 4. The Verizon phone uses CDMA instead of SIM card. The only way to disable the phone is to turn Airplane Mode on. But this also disables the GPS. To make Verizon phone battery life viable for backpacking, you would need to keep the phone in airplane mode and temporarily toggle airplane mode off every time you want to get a gps read. The hassle factor would depend on how often you need a read. Alternatively, for short trips you could carry a recharging solution."

Which is why I made the suggestion that Gaia GPS give us a way to toggle Airplane Mode from within the app.

The curious side of me got me locked into a few rounds of searches..... Apparently, you can jailbreak the iPhone, then install SBSettings back to the phone from cydia (the equivalent of apples app store) for jailbroken phones.... (app store still works fine as well).....

I actually looked for a store in your area that offers an unlocking service and www.GadgetFixNW.com was ironically still open ... the two main iPhone "techs" are gone for the day but will be back tomorrow and can most likely answer if they personally can do it for you...

Bottom line is YES it can be done..... question is finding a vendor locally to do it for you if you're not comfortable attempting on your own.


I'll work on additional options..... personally, I'd just jailbreak it myself with redsn0w, then download SBSettings and try it... if it doesn't work, restore from iTunes.

I was VERY apprehensive doing it the first time... but it was INCREDIBLY easy.

Edited by abrown3mtg on 06/17/2012 18:54:05 MDT.

... whether what you describe allows independent enable/disable of the cell service and GPS receiver; and I'm not running iTunes anyway, being on a Linux machine.

Wouldn't it be easier to just vote for my suggestion (that Gaia GPS add an Airplane Mode enable/disable button) than to go through all the jailbreak stuff?

I'm trying to encourage a non-hacker solution to this annoying issue with the CDMA iPhones, to make backcountry navigation just a little bit more convenient.

I found someone in your area that is confident they can accomplish it (local bend unlocking service)..... They are going to trial run it tonight and get me an answer tomorrow.

My thoughts are if you jailbreak, the phone will only be utilizing gps and not wasting excess battery searching for signal during times that it is toggled on...... for extended trips, the longer you can milk that battery for, the more useful the app is going to be..... if you could potentially leave the phone on and actively use the gps more frequently with the same energy consumption, it would make more sense to just make your device itself more efficient than adding a toggle option to a program and not really resolving the issue completely.

if you can double the amount of use the battery would allow by jail breaking vs the toggle/search, what would make the most sense? It kind of like using a windscreen to conserve and carry less fuel.....

get a mophie juice pack.... case that double-triples your battery life......

doesn't add the in app toggle option, but would create less frantic and reserved usage... and they are really nice when traveling.... I LIVE on my phone (have multiple batteries for my blackberry, and had chargers in my car, desk, office, and practically every room of my house) when i had the iPhone for business use.... I could get through the day with the mophie in most cases.

Granted in this forum (where its common to cut the handles off ti pots, the extra weight can't be that great an add on, granted lighter than adding a gps stand alone unit!

Being able to control all aspects of the CDMA (Verizon) version of the iPhone would be ideal. I like being able to tweak things. If you find out that the jailbroken phone allows access to such control, that's one option.

But not everyone is comfortable with hacking expensive phones. So for them, being able to enable/disable Airplane Mode from within Gaia GPS, as opposed to having to exit the program, go to Settings, make the change, then go back into Gaia GPS, get a fix, then exit the program, and go back to Settings every time they want to get a fix would be a boon.

"Being able to control all aspects of the CDMA (Verizon) version of the iPhone would be ideal. I like being able to tweak things. If you find out that the jailbroken phone allows access to such control, that's one option."

If you like to have any control over your device, or tweak, what are you doing owning an iPhone? Go buy an Android phone.

Edit: I don't know how iOS deals with permissions, but I'm guessing since you need to jailbreak to control the GPS/Airplane, it can't be controlled by an app unless you're jailbroken. So it's probably a dead end.

Edited by tekhna on 06/17/2012 19:49:46 MDT.

Andrew, I'm not here to debate iPhone v. Android; nor did I start the thread asking for advice on how increase my pack weight by packing a solar charger. You can start your own thread about these matters if you wish, but I'd like to get this thread back on track.

I'm just asking for users of Verizon iPhones who use the Gaia GPS app to vote for an idea that I think would be useful to us/them.

It's drifting because it's probably not possible to do without jailbreaking. Otherwise someone would have implemented it already.

The Verizon will work with no cell coverage, but the cell function must be turned on. After phone cannot communicate with a cell tower, it switches to the GPS chip. The means every time you use it, it is going to use more battery power than needed.

Yes, you can jail-break it but that presents a whole lot of new potentially troublesome problems.

As to iPhone vs Droid, depends what you use your phone for. The integration between iPhone, iPad, and computer is important to me and the Apple products need my needs seamlessly. But I don't take my phone or a GPS backpacking so it is a mute point :)

"It's drifting because it's probably not possible to do without jailbreaking. Otherwise someone would have implemented it already."

But that's not what the thread is about. Not about independently turning off cell/gps on a stock iPhone, but about asking the creator of Gaia GPS to implement a suggestion to allow control of Airplane Mode from within the app. Read the OP.

I want the same feature for the ATT Iphone too. This is a great idea, Jack! I emailed Apple asking for a GPS-only mode or backpackers but have been ignored. I recommend all email apple asking for a GPS-only mode button. When I hike the John Muir Trail for 27 days I'm out of cell range but would like to use the GPS on some days (like when there is a 30 year snowpack record and you're walking over snow for 6 miles and want to see where the trail is).

I was truly only attempting a way to help in the most efficient manner possible (including reaching out to find a solution local to you).

If you review, I never brought up the android vs iPhone topic.......

I apologize for trying to find a solution that would resolve your issue with verizon's limitations allowing you to use the GPS feature alone which seemed to be your ultimate desire and suggest a solution you may not have considered.

I'll bow out at this point.... and simply post if it is determined that the jailbreak solution will work in the event other members not against a jailbreak would benefit from the response.

Best of luck.

+1. The AT&T phone has the same issue.

Hiker mode would be ideal.

A button to toggle airplane mode in the app would be nice.

Roleigh-

You can use GPS only on the AT&T iPhone.... go into settings, general, network..... then disable 3g and cellular data, GPS remains active :)