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Is the iPhone 4's GPS supposed to be this crappy?

iPhone 4 GPS works perfectly for me, even for visits to New York City.

Typically using Maps to see current location and another app for turn by turn directions in background.
 
kdarling said:
Which directions were you driving? Where was the phone placed? What kind of car was it? (Some have metallized windshields.) There can be a lot of factors.
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Phone was placed in a cradle holder held by a vent, using a Mazda 6 rental car, driving around Austin and then north to Dallas from there. First day clear blue sky, second day cloudy weather, same result, barely could hold on to a signal.

Today though it's back to its old self, no loss of signal after driving around Dallas for the whole day. The only thing I did was turn WIFI back on. I'm surprised it would make this much of a difference since I thought the triangulating feature is rather gimmicky, but after this I'll never turn it off now. :D

I'm still convinced that there are software quirks going on behind the scenes that's causing these hiccups, but so far I'm happy to see the problem cleared up for now.
 
JustLeft said:
Add me to the list of those with verizon phone gps issues. Returned two ip4's back to Verizon as a result.
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Did you have wifi turned off when you were using it? As long as mine's any loss in GPS signal is minimal, although it still tends to fluctuate and lose it more than my old GPS Cradled-iPod did.
 
My phone loses signal repeatedly for a few seconds at a time when in MotionX. This is not visible in the native Naps app as the pinging is not fine enough to display very brief loses of signal. If I turn off cellular data in the settings the problem diapers and the GPS functions flawlessly.
 
Unless something has drastically changed - I believe the iPhone uses your cellular network as the GPS - not satellites in space. So if your carrier signal is weak - your ability to triangulate will too.

If the IP4 does have an actual satellite GPS receiver - then I take back everything I ever said about their antenna design...
 
Big-TDI-Guy said:
Unless something has drastically changed - I believe the iPhone uses your cellular network as the GPS - not satellites in space. So if your carrier signal is weak - your ability to triangulate will too.

If the IP4 does have an actual satellite GPS receiver - then I take back everything I ever said about their antenna design...
Click to expand...
It uses A-GPS which uses cell tower triangulation to get a quick fix when starting up THEN it uses "real" GPS to get an accurate location and for tracking.
 
It's had a real GPS since the 3G. It uses the cellular and wifi network to approximate your location so it can more quickly acquire a GPS fix. The satellites are in different positions depending on where you are on the globe. The cellular and wifi data speeds the signal fix and also provides location information when indoors or otherwise obscured from GPS.


Sent from my iPhone using Tapatalk
 
My understanding is that of the data it receives from the cell tower or wifi network is erroneous it can actually mess up the true GPS or significantly slow down position acquisition. If the cell tower says tour are in Texas but your in Arizona it will have the wrong positions for the satellites to work with. I think what I'm seeing has to do with the location information being sent from the tower each time the phone connects to a new tower. This seems to be momentarily confusing the phone even if it already has a satellite lock.


Sent from my iPhone using Tapatalk
 
morsecp said:
My understanding is that of the data it receives from the cell tower or wifi network is erroneous it can actually mess up the true GPS or significantly slow down position acquisition. If the cell tower says tour are in Texas but your in Arizona it will have the wrong positions for the satellites to work with. I think what I'm seeing has to do with the location information being sent from the tower each time the phone connects to a new tower. This seems to be momentarily confusing the phone even if it already has a satellite lock.
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I leave my wifi on all the time and have had no issues with GPS tracking. *shrugs*
 
So if you were in a boat 250 miles away from land, or lost in the great woods of Canada... You could actually acquire a signal and location??? :eek:
 
morsecp said:
My understanding is that of the data it receives from the cell tower or wifi network is erroneous it can actually mess up the true GPS or significantly slow down position acquisition. If the cell tower says tour are in Texas but your in Arizona it will have the wrong positions for the satellites to work with. I think what I'm seeing has to do with the location information being sent from the tower each time the phone connects to a new tower. This seems to be momentarily confusing the phone even if it already has a satellite lock.


Sent from my iPhone using Tapatalk
Click to expand...

Wrong

GPS location will over rule any previous location

A-GPS makes locating you faster not slower. It allows for an approximation of location using data, but after that GPS takes over.

You can put your phonw in airplane mode, you will still get a GPS fix but it will be slower(or similar speed) to acquire than the normal A-GPS method.

There are 24-32 GPS satellites currently in space vs hundreds of cell phone towers
 
Big-TDI-Guy said:
So if you were in a boat 250 miles away from land, or lost in the great woods of Canada... You could actually acquire a signal and location??? :eek:
Click to expand...
Yeppers. It would take longer to acquire because it wouldn't be able to triangulate quickly using the towers but it would find and track you within a minute or two accurately.
 
Big-TDI-Guy said:
So if you were in a boat 250 miles away from land, or lost in the great woods of Canada... You could actually acquire a signal and location??? :eek:
Click to expand...

signal yes, location... not so much just using the built in Maps App

certain gps apps will give you a longitude and latitude

IF you have a gps app that lets you save offline maps then yes you will have a signal and location ( anywhere in the world theoretically)
 
Shenaniganz08 said:
signal yes, location... not so much just using the built in Maps App

certain gps apps will give you a longitude and latitude

IF you have a gps app that lets you save offline maps then yes you will have a signal and location ( anywhere in the world theoretically)
Click to expand...
It gives you the location but if you don't have maps on the device it won't do you any good. Just clarifying.
 
morsecp said:
My understanding is that of the data it receives from the cell tower or wifi network is erroneous it can actually mess up the true GPS or significantly slow down position acquisition.
Click to expand...

Note that the cell towers don't tell the phone anything except their id.

The phone can use that cell id in two different ways, depending on what kind of location request has been made, what system is ready, and what is turned on:

1) Cell id locating. Apple has created their own database of cells (not towers, cells). The phone asks the Apple server for a rough location using that cell id.

Btw, I don't believe there's any triangulation. That would be too flaky using signal strengths, even if it did have three or more cells in view.

2) As part of the initial A-GPS request. When a phone makes an Assistance request over the internet, it sends the currently connected cell id with it.

Assistance servers take that id, plus the phone id, and make a background request to that carrier to resolve the cell id to a rough location. This of course assumes the carrier cooperates with such requests.

The location is then used by both the Assistance server (to provide the correct satellite info) and the phone (as a seed location).

--

PS. E911 is a different animal. CDMA carriers will request your phone's GPS location and forward it to the 911 center. GSM carriers triangulate your phone using cell towers alone (they don't talk to the phone), which is usually far less accurate.
 
Second, day, still no major issues. Even went geocaching with it.

I'm too lazy to turn off WIFI again to see if the problem starts up all over again, but it's too coincidental for the problem to have gone away the minute I turned WIFI back on. All it's supposed to do is expedite a GPS lock, but once that's done I presume WIFI doesn't play a role in MAINTAINING the GPS lock, yet it seemed to be doing so in my case.

Or, it could be solar flares. :p
 
Shenaniganz08 said:
Wrong

GPS location will over rule any previous location

A-GPS makes locating you faster not slower. It allows for an approximation of location using data, but after that GPS takes over.

You can put your phonw in airplane mode, you will still get a GPS fix but it will be slower(or similar speed) to acquire than the normal A-GPS method.

There are 24-32 GPS satellites currently in space vs hundreds of cell phone towers
Click to expand...

This is not true. It depends on how the software was written. The phone receives cell tower location data from cell towers continuously, while there is a signal. This is how location aware applications that aren't currently running receive your location data and alert you about your proximity, say in a task management app that alerts you when you are near the grocery store.


Sent from my iPhone using Tapatalk
 
Shenaniganz08 said:
Wrong

GPS location will over rule any previous location

A-GPS makes locating you faster not slower. It allows for an approximation of location using data, but after that GPS takes over.

You can put your phonw in airplane mode, you will still get a GPS fix but it will be slower(or similar speed) to acquire than the normal A-GPS method.

There are 24-32 GPS satellites currently in space vs hundreds of cell phone towers
Click to expand...

Put your phone in airplane mode and try to get a GPS signal, meaning your location is "pinging" in the native maps app. It won't happen. The airplane mode disables the wireless receivers in the phone including GPS. The only receiver that can be turned on in airplane mode is the wifi antenna.


Sent from my iPhone using Tapatalk
 
LincolnsiPod said:
Second, day, still no major issues. Even went geocaching with it.

I'm too lazy to turn off WIFI again to see if the problem starts up all over again, but it's too coincidental for the problem to have gone away the minute I turned WIFI back on. All it's supposed to do is expedite a GPS lock, but once that's done I presume WIFI doesn't play a role in MAINTAINING the GPS lock, yet it seemed to be doing so in my case.

Or, it could be solar flares. :p
Click to expand...

The Verizon iPhone either has a problem with the design of the Qualcomm chip or a bug in the baseband firmware. I've owned both the AT&T iPhone 4 which handled places that my stand-alone PND never could handle correctly. The Verizon iPhone is just as solid at getting a lock in weird situations (under bridges, in cities where you get bounced signals from buildings), but does drop GPS lock randomly and for no apparent reason.

A hope is to see that whatever 4.3 version that comes out for the CMDA model includes an updated baseband.
 
Krevnik said:
The Verizon iPhone either has a problem with the design of the Qualcomm chip or a bug in the baseband firmware. I've owned both the AT&T iPhone 4 which handled places that my stand-alone PND never could handle correctly. The Verizon iPhone is just as solid at getting a lock in weird situations (under bridges, in cities where you get bounced signals from buildings), but does drop GPS lock randomly and for no apparent reason.

A hope is to see that whatever 4.3 version that comes out for the CMDA model includes an updated baseband.
Click to expand...

That's been exactly my experience, I could get a solid lock inside an airport terminal or even my hotel room, and yet it will randomly lose the signal under a clear blue sky. Weird.
 
Big-TDI-Guy said:
So if you were in a boat 250 miles away from land, or lost in the great woods of Canada... You could actually acquire a signal and location??? :eek:
Click to expand...

Technically correct, though the phone relies on a data connection to actually load the map information., so all you'll see is the blue dot on a field of gray. If you had maps pre-loaded on the phone, it would be able to show you where you were.
 
LincolnsiPod said:
Second, day, still no major issues. Even went geocaching with it.

I'm too lazy to turn off WIFI again to see if the problem starts up all over again, but it's too coincidental for the problem to have gone away the minute I turned WIFI back on. All it's supposed to do is expedite a GPS lock, but once that's done I presume WIFI doesn't play a role in MAINTAINING the GPS lock, yet it seemed to be doing so in my case.

Or, it could be solar flares. :p
Click to expand...

I thought I was lazy, but you're bringing it to a whole new level.
 
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