Verizon iPhone 4 GPS wildly inaccurate

Question

Verizon iPhone 4 GPS wildly inaccurate

I use RunKeeper and RunMeter to track my running. Both worked fine on my iPhone 3G, albeit a little slow.

Upgraded to the Verizon iPhone 4, which, unlike the AT&T iPhone 4, has its GPS functionality shared on the main processor (instead of a dedicated processor). I am seeing all kinds of zig-zags when all I do is run down the street.

I live in a semi-rural area with a clear view of the skies. I have no problem getting a solid GPS signal. I usually re-start the phone before running so no other apps are present. I've tried with WiFi turned on and off.

Two days ago I convinced Verizon to swap my phone for a new one to see if it is the phone itself. So today I have TWO Verizon iPhone 4's. I installed the same software on both and went for a 10-minute walk. BOTH show wild zig-zags in what should be a straight path.

I called Apple and they said they could only help me if the problem shows up in the built-in maps. The problem with that is I don't see a way to make the built-in maps app keep track of its route so I can review it for zig-zags. It also appears that it may make an effort to glue me onto roads (especially in "Directions" mode, even with "Walking" chosen). However, when I turn on the new little triangle that shows the direction of travel, it constantly shifts to the left and right as I walk in a straight line. If this little triangle is based on GPS, then it is showing the same inaccuracy. However, if it's based on the internal gyros, it may simply reflect my natural motion while walking.

I believe Apple and Verizon are in serious denial over this issue. There is a problem. I've observed it two running apps from two different companies, and I've observed it on two different CDMA iPhone 4's running simultaneously. There is a flaw in the hardware or OS software that needs to be fixed, and you can't fix problems that you deny having or that you obscure by the way the built-in apps are coded.

Anyone else having problems with GPS on the VERIZON iPhone?

Craig

CDMA iPhone 4, iOS 4, iOS 4.2.6

Posted on Mar 16, 2011 9:58 AM

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Answer 1

sn4p2k

Level 4

1,228 points

Mar 16, 2011 10:06 AM in response to DesiredAliasGoesHere

If they refuse to fix it your only option is to go back to the AT&T iPhone. You said you tested this on a iPhone 3g that doesn't mean that the at&t iPhone 4 will work either.

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Answer 2

Mar 16, 2011 2:31 PM in response to DesiredAliasGoesHere

I noticed using the maps program in my verizon ipone it takes a long time to start navigation when i am in my vehicle and a long time to find destinations

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Answer 3

Mar 17, 2011 7:18 PM in response to DesiredAliasGoesHere

I also have issues with the GPS on the Verizon iPhone4 being unstable. My experience is that while driving and using any of my GPS apps (Motion X, Google Maps and others) the GPS tends to hang and sometimes jumps way off the path being traveled only to return again in a short while. I have also noted what can be described as a meandering track left be the GPS app while moving in a straight line. These are the same apps that I had used with my AT&T iPhone4 without any of these distracting issues.

BTW, when using an external GPS receiver tethered to the iPhone4 all of these issues disappear and the GPS representation is rock solid and more accurate.

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Answer 4

Mar 18, 2011 3:18 AM in response to DesiredAliasGoesHere

I've noted that when using the 'Maps' application that came with the VZW iPhone (Google Maps), that the GPS is far better at locking on, maintaining a connection and tracking accurately. HOWEVER when using other 3rd party apps, the reliability drops considerably. Perhaps (and I'm speculating here), being the GPS component of the Verizon iPhone is an integrated component in lieu of an independent component as with the GSM version, that the SOFTWARE has to be tuned or optimized for this hardware configuration. That would certainly explain as to why the Maps app works better as it likely was 'optimized' for this hardware, but the majority of the other apps out there are not taking this into account... at least not yet anyway.

What does everyone think? Sound plausible? Comments?

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Answer 5

Mar 18, 2011 8:48 AM in response to brassman1234

The problem with using the built-in Maps application is that it doesn't leave any kind of breadcrumb trail showing where you've been. It's hard to see 50' or 100' deviations in the path at the scale it normally displays at.

Furthermore, in some modes it pins your position to the nearest road. It's hard to know if it's really showing you the raw GPS position data or not.

Applications that consume GPS data should not have to make adjustments like this. The GPS data should be good as supplied from CLLocationManager in the SDK. Furthermore, even though the CDMA and GSM iPhone 4's have completely different hardware solutions for GPS, from the perspective of third-party apps they should look identical. Imagine if graphics drawn to a Verizon iPhone screen were "sometimes" shifted 20 pixels in a random direction and it was up to the programmer to adjust. That would be unacceptable. What if "sometimes" contact information for a person contained their correct phone number and other times it contained someone else's phone number and third-party programs were expected to sample the database several times and present the "average" phone number.

No, this is a serious bug and it needs to be dealt with by Apple.

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Answer 6

Amfab

Level 1

0 points

Mar 18, 2011 9:31 AM in response to DesiredAliasGoesHere

Same issues here with TrailGuru and Trails
Iphone 3g and 3gs had no problems.
Verizon iPhone with same apps are all over the place. Tracking is now useless.
Quite upsetting

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Answer 7

Mar 18, 2011 3:27 PM in response to DesiredAliasGoesHere

Make sure you send your concerns to Apple's feedback channel.

Here's the link. The more people that report an issue, the better chance it'll get addressed.

http://www.apple.com/feedback/

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Answer 8

pelorus

Level 1

9 points

Mar 19, 2011 9:15 AM in response to Neil van den Berg

Same issue w/ Verizon iPhone. Purchased Verizon iPhone4 and found GPS signal drops out regularly. Had ATT iPhone 3g and Apps ran w/o dropping signal. I use Motion X GPS Drive and the Verizon phone drops GPS where as ATT did not. This is more prevalent when using blue tooth head set while driving. It also drops on push notifications when they arrive. I've sent the same info to Motion X folks. They have been very responsive. Maybe through them they can get Apple to move on this.

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Answer 9

Mar 19, 2011 9:22 AM in response to brassman1234

I've already sent feedback to Apple and agree that others should do likewise. I've also sent details to Gizmodo, MacRumors, and other tech sites, plus Fox business news and other news site, and Verizon corporate. 🙂

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Answer 10

jbob9999

Level 1

0 points

Mar 19, 2011 10:03 AM in response to DesiredAliasGoesHere

Just wanted to confirm that I have exactly the same issue with the TomTom and Navigon app. Signal constantly drops and takes a long time to lock back on. No issues with my old iphone 3gs on ATT.

Is anyone using a car GPS app that is unaffected by this issue?

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Answer 11

Mar 19, 2011 12:06 PM in response to pelorus

You know, I thought that maybe it was just me being a little too observant, but I too seem to notice that when using the bluetooth audio in my car, the problem is even worse. The Motion X GPS Drive app is virtually unusable due to the GPS signal contantly dropping. MapQuest Mobile is a little better (not by much though). The app that's least affected appears to be the Maps app that comes with the phone. I haven't gotten any feedback response back from Apple yet. I know that some of the high dollar Nav apps (like Tom Tom) should certainly take note because after paying that kind of cash, you'd expect it to work!

Message was edited by: brassman1234

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Answer 12

Mar 19, 2011 12:04 PM in response to DesiredAliasGoesHere

On a side note, has anybody tried Verizon's PAID Nav App, VZ Navigator? I wonder if theirs has these same issues? It's priced right up there with the most expensive Nav apps. I'm not saying anything else, unless somebody out there has used it and says "It works perfectly".

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Answer 13

Mar 19, 2011 4:17 PM in response to brassman1234

Keep in mind that an app might SEEM to work or seem to work better than others because it is taking steps to mask this problem. Remember the problem is that the Location Manager on the device is feeding crazy data to whatever navigation program is using it. If the navigation program (be it Maps, VZ Navigator, or a third-party app) does anything like force the position to be on the nearest road, test for unrealistic position/direction/speed, or simply smooth the data points using some kind of smoothing algorithm (see, for example, http://en.wikipedia.org/wiki/Exponential_smoothing) then they're masking the real problem.

In some modes, the built-in Maps application will glue you to roads, thus hiding any deviations to the left or right.

My RunMeter application applies a smoothing algorithm so its deviations seem very slight and "gentle".

My RunKeeper app, however, uses raw data directly from the Location Manager and as a result shows me zig-zagging and back-tracking.

So if VZ Navigator appears to show a smooth course, it only demonstrates that they're going out of their way to correct the errors being presented to them by Location Manager. The problem still exists; it's just being masked.

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Answer 14

Mar 19, 2011 4:41 PM in response to DesiredAliasGoesHere

I hear you. But there obviously is a problem here as apps which did work just fine with the GSM iPhone are now having trouble with the CDMA iPhone. HOPEFULLY it's just a software thing because being the GPS hardware is different (integrated on the Qualcomm chip in lieu of independent chip), the worse case scenario would be that this iPhone simply doesn't have as good as a GPS as it's GSM cousin.

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Answer 15

Mar 19, 2011 5:35 PM in response to DesiredAliasGoesHere

I'm not sure if this problem is widespread or not. Some people have reported that they've gotten their phone replaced and the issue wasn't present in the new phone. Somehow I really doubt that it's a hardware issue. It's more likely something that triggers it as I feel that there is some common denominator here. Keep postin' and keep sending feedback to Apple. I did (and still haven't heard a response)...

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Verizon iPhone 4 GPS wildly inaccurate