The downside of buying a used iPhone

[MikeFromMesa]

OK. I bought a used iPhone 6 to use as a nav device. As I explained in an earlier thread the idea was to use it over wifi only and to interface it with my vehicles info center using CarPlay. I bought the phone, set it up and took it, along with my car, for a spin today. I wish I could report good news, but I am afraid not.

1) I recently upgraded my old phone with a new one and when I bought the new phone they gave me a new SIM card as well. Thus I still have the old SIM card, which is not active, but is a valid SIM card.

2) I put that SIM card in the iPhone 6 and it recognized the card and showed me the normal network information. Of course the SIM is not active, but I did not try to make a call. Instead I turned on my mobile hot spot and set the iPhone 6 wifi setting to that hot spot. The phone had no problem accessing the internet over the hot spot.

3) I started Waze, set up a route and started out. After about 1/2 mile I realized that the phone was no longer showing my correct location and when I got to where I wanted to go the iPhone showed me as being about 1/2 mile from where I was. When I looked more carefully I saw that the Waze display had the caption "No GPS. Estimating location".

4) I then tried some other nav software, but all of it told me the same. No GPS information. What I don't know is whether the issue has to do with the inactive SIM card or if the new and refurbished phone doesn't have a working GPS system. So, given all of this, some questions:

a) Does an iPhone need to have an active SIM to be able to get GPS signals? I know that it can estimate my location based on internet information but I am asking specifically about GPS signals.

b) Is there any way for me to be able to determine if the lack of GPS is because of the inactive SIM card or because the GPS hardware in the phone is not working? If the issue is the SIM card I should return the phone as I don't really want to pay an extra monthly fee to use Waze or Sygic. If it is the GPS hardware I need to return it since it does not work.

Thanks for any help. If it makes any difference the iPhone was bought through a 3rd party, not Apple, and it was not refurbished by Apple. It looks great, screen and all, and seems to generally work properly except for the GPS.

 

[IWT]

Mike,

I'm really sorry about the various misfortunes that have beset you recently.

As far as I know, you don't need a SIM card at all in any iDevice, including the iPhone, if you are not going to make any calls and if you don't require any cellular function. Think of the iPod Touch which, in effect, is an iPhone with no SIM card or cellular signal. You do still have GPS for location purposes. That goes for an iPad with WiFi only.

The SIM-less iPhone, the WiFi only iPad and the iPod Touch can all connect via a cellular Hotspot of another iPhone with a SIM card.

(You will know already, I'm sure, that you cannot use an iPhone as a Hotspot unless you have a cellular signal. So, no SIM card, no cellular, no Hotspot).

I can't explain your apparent lack of GPS function. I may be misremembering your previous post(s), but did you not have an issue with Apple ID?? Were you the one who got the iPhone from a third party who had failed to set up the iPhone properly "as new" and from whom you could not get their Apple ID & PW? Forgive me if I've got that all wrong. But if I'm right, I wonder if that could be an issue here?

Ian

 

[MikeFromMesa]

I'm really sorry about the various misfortunes that have beset you recently.

Thanks. Me too ...

As far as I know, you don't need a SIM card at all in any iDevice, including the iPhone, if you are not going to make any calls and if you don't require any cellular function. Think of the iPod Touch which, in effect, is an iPhone with no SIM card or cellular signal. You do still have GPS for location purposes. That goes for an iPad with WiFi only.

That has been my thinking as well. I don't see why I should need a SIM card to get a GPS signal and if, in fact, that is the case, then I will just return the iPhone to Amazon. I just wanted to be sure before I did that.

I suppose I should also check with the Apple people but I have had some bad information given to me by AppleCare and thought I should check on the forum first. Sometimes the people on these forums have better information than the person I get at tech support.

Were you the one who got the iPhone from a third party who had failed to set up the iPhone properly "as new" and from whom you could not get their Apple ID & PW? Forgive me if I've got that all wrong. But if I'm right, I wonder if that could be an issue here?

No. That was not me. I have set up enough iPhones over the past years to be familiar with the process.

In this case the refurbishing was done by some company that sells its iPhones through Amazon and I should be able to just return the phone, but I want to know if there really is a hardware issue before I do that as I would not want to return it and ask for a replacement only to find that it as well has the same issue.

All of this was supposed to be a low cost way to use Waze or Google Maps through the Sync 3 system on our vehicle but, like other times I have tried to save some money, the downside sometimes is bigger than the upside.

 

[IWT]

Mike,

I found this discussion on the Apple Support site. One or two replies were inaccurate, but the consensus was that GPS should work within certain limitations. May be worth a read.
does gps work without sim card? - Apple Community

This article may also help?? Access Denied It has more to do with Maps etc.

This too: Using iPhone GPS without a sim card | GPS Phones forum

Other members may chime in with cleverer ideas.

Ian

 

[MikeFromMesa]

Mike,

I found this discussion on the Apple Support site. One or two replies were inaccurate, but the consensus was that GPS should work within certain limitations. May be worth a read.
does gps work without sim card? - Apple Community

This article may also help?? Access Denied It has more to do with Maps etc.

This too: Using iPhone GPS without a sim card | GPS Phones forum

Other members may chime in with cleverer ideas.

Ian

Thanks, but I did what I should have done before I posted. I shut down the iPhone 6, removed the valid SIM from my regular phone and placed it in the 6. Started it up, verified that I could make a call with the SIM and then tried the navigation software. I got the exact same error message about no GPS so I think that solves the problem. The GPS system in the refurbished phone just does not work.

Fortunately I bought it from Amazon so it is going back, but not until I put the SIM back in my new phone.

This was really too bad. The refurbished phone looked new and aside from the GPS issue it worked perfectly and was inexpensive. I guess I will try again but this time verify before that the refurbishing company fixes the GPS as well as the phone stuff.

 

[MacInWin]

Mike, I tested what you want to do and it worked perfectly on a 5s I have. No SIM, GPS works fine. The ONLY factor that the SIM card plays in navigation is that if the GPS signal is dodgy (buildings around, trees blocking, etc) then then system triangulates from cell towers for a rough location. No SIM card means you will be relying on all GPS, but 99% of the time, that's just fine.

 

[chscag]

@Mike:

Be careful buying a used or refurbished phone from Amazon. Even though Amazon will make the purchase good, there are a lot of not so honest resellers that are selling goods through Amazon. I had an experience with them some time ago when I purchased an iPhone 5C from them for my wife. The phone was advertised as new which meant I could purchase Apple Care on it. Apple refused the Apple Care purchase and informed me the phone I purchased was actually a replacement phone they supplied under warranty for another that was defective. The phone was new and I never had a problem with it but it was falsely advertised. Amazon offered to refund my money but since the phone was new we kept it.

 

[MikeFromMesa]

Mike, I tested what you want to do and it worked perfectly on a 5s I have. No SIM, GPS works fine.

I admit that I am not sure about any of this, but I ran both Waze and Sygic on the iPhone 6 without a valid SIM card but connected to a cell hot spot and I noticed two things.

First, the software showed me located a long way from where I actually was - perhaps as much as a half mile, and I was in the middle of a reasonable sized city with very good cell signals.

Second, when I drove the software did not update my location except in very large jumps. That is, it showed me at home when I was perhaps 3 or 4 miles away and then, when I told it to "recenter" the display, it jumped to near my current location. The actual location was so far off that the proposed route was completely wrong. I knew where I was going, and I knew the best and fastest way to get there, but since the software thought I was somplace completely different it set up a very different routing.

I don't really understand any of this since there is good cell service where I was and there are no tall buildings. I live in the Phoenix metro area and outside of downtown Phoenix there is almost no building over 1 or at most 2 stories high.

As I mentioned the phone kept telling me there was no GPS, but my regular phone and my wife's iPhone worked properly. This evening I removed the valid SIM from my phone and put it into the refurbished iPhone to test that and it also told me that there was no GPS signal, so I assume that means there was no GPS signal and that the phone is the culprit here. I scheduled a return for the phone but before I actually send it I will call them and see what they have to say. Perhaps they can explain it, or perhaps they will just send me a replacement.

As I mentioned above the refurbished phone seemed perfect in every way. The screen was crystal clear and free of any marks, the case looked new, the OS and apps all worked perfectly (except for the navigation stuff and the No GPS message) and it seemed like a great buy at only a little over $100. I was going to give it a 5 star review on Amazon until I found the GPS issue.

 

[MacInWin]

@Mike, navigation has almost nothing to do with cell coverage and almost everything to do with GPS signals from the satellites. Keep that in mind. You do NOT need SIM cards or cell coverage for navigation and trying to navigate with only cell triangulation will be very, very poor. The technique for cell triangulation is based on strength of signal, which can vary wildly based on antenna positioning, reflections from buildings, intervening materials, etc. Truly, triangulation is, at best, awful. I'm actually surprised it was within a half mile.

If the phone said there was no GPS, that explains why the navigation software was so poorly functioning. I would recommend you not bother with the call, just send the phone back and get a refund, then start over with a purchase.

One thing that may play a part. When GPS starts up cold, it has no idea where it is. The receiver needs to listen for the satellites it can hear and then listen for one of them to broadcast the ephemeris, or the data on where the satellites are at the time. Then the GPS starts trying to find a solution for where it might be, based on the satellites it can "hear" and the ephemeris it downloaded, gets a rough solution, tries again and continues the process until it gets a solution that satisfies the built in quality standards for the unit. If the receiver moves during that process, the process has to start over from scratch, although it doesn't have to wait for the ephemeris data. So, the SIM cards provide a "I'm about here" location to speed up that initialization process. EDIT: But you don't HAVE to have a SIM card, the system will find the location eventually even with no clue as to where it might be.

You didn't say, but if you fired up the iPhone and started driving the route before the GPS could get the first fix, your movement caused the initialization to reset and reset and reset.

So, to test, take the phone outside where you have a clear view of the sky and fire up the GPS software. Let the system just sit there, unmoved, for a few minutes. Five should be more than enough, it may only take 2-3. If the system reports that it now has a fix, your software should show where you are and be stable.

Once it has a fix, keep the phone powered on and it will be constantly updating the location in the background, so you won't have to repeat the process.

Hope that helps some.

 

[IWT]

Ah Mike, you've had a rough time with this and a few other things you've posted about.

I'm sorry for your predicament - the excitement of what seems a great purchase, then the disappointment of its not working as it should.

At least everyone agrees with my first post/comment that GPS should work without a SIM. Not much consolation for you though

Ian

 

[dtravis7]

What app do you guys use for GPS? That is something I have not done much with at all. I have a 5s with no SIM card and would like to try it. What app should I get? Sorry if this is a dumb question but I have never once used GPS on my iPhones.

someone said just use maps. It does show my exact location.

 

[MacInWin]

Depends on what you want in GPS. For driving around, Waze is free (ads show up when you are stopped at a light). It has traffic alerts and will reroute around a blockage. If you want to go off-road, there are apps in the store for that, but I'm not that familiar with them. Inrix also does traffic alerts and some routing. MotionX will allow you to save a track for where you have been, but has no routing capability.

 

[MikeFromMesa]

What app do you guys use for GPS? That is something I have not done much with at all. I have a 5s with no SIM card and would like to try it. What app should I get? Sorry if this is a dumb question but I have never once used GPS on my iPhones.

someone said just use maps. It does show my exact location.

Make sure your location services are set to ON. If they are off you will not have any GPS information. Check under Privacy in Settings.

 

[pm-r]

What app do you guys use for GPS? That is something I have not done much with at all.

As Jake already mentioned, what are you wanting to do with any GPS iDevices you may have???

And the first thing to do is to double-check and make sure your iDevice actually has proper GPS capabilities. Not all models do.


- Patrick
======

 

[MikeFromMesa]

And the first thing to do is to double-check and make sure your iDevice actually has proper GPS capabilities. Not all models do.

I am not questioning your statement, but what iPhones do not have GPS capability? I thought that all current smartphones could handle GPS. I know that wifi iPads can not, but I thought that all cell compatible phones and tablets had GPS capabilities.

 

[chscag]

All iPhone models from the 3G to the present have GPS capability. You would have to find an antique iPhone in order to find one without it. I guess that's what Patrick was referring to.

 

[MacInWin]

If you really want to know how GPS works, watch this video at YouTube: YouTube

It is accurate and pretty simple in the description of how it works. One interesting fact is that every day the satellite clocks lose 38 microseconds because the satellite is moving and as Einstein said, moving clocks run slower. So the USAF updates the clocks against the master clock to keep everything accurate. (As a trivia question, if you didn't adjust the clocks the system would still work pretty well because all of them should lose about the same time and the fixes would still be accurate. However, over time the small differences in orbital speeds would cause the clocks to fall out of sync and fix accuracy would degrade. Bear in mind that the speed of light is about 1 foot in a nanosecond, so it doesn't take many nanoseconds of drift to produce some major error.) In addition, the USAF tests the orbital data to see if the satellite has moved, and if so, updates the ephemeris appropriately. The bit in the video about the differential GPS and WAAS is there to make sure that aircraft using the system have the most accurate fixes. What they do is to survey a spot very accurately, then put a GPS receiver there and constantly compute where the GPS data thinks the receiver is. The difference between the very accurate survey data and the GPS calculated position is then broadcast to all the GPS receivers nearby to adjust their fix by that differential. In WAAS, the differential data from all over the US is transmitted by satellite to all receivers in the US and the receiver uses the data for the nearest differential spot as the correction.

I remember back in the early days when President Reagan released the accuracy limits on GPS how excited everybody was about suddenly being able to know where you are to within 5 m! Geocaching took off as a sport, road navigation suddenly became really accurate and GPS receivers for PDAs became a popular item. (Before smartphones for the young'uns.)

 

[MacInWin]

One more thing: The way that the cell service does the most to speed up the GPS fix is that your cell phone can get the almanac data faster over cell using a bit of your data allowance so that as soon as it has ephemeris data from 4 satellites, you have a fix. Normally that's in less than a minute, which can be disguised in the start up routine for the GPS application on the phone. To you, it looks practically instantaneous, but a lot of stuff is going on in the background to make it happen.

EDIT: One more one more thing. GPS (or SatNav) will be showing where you WERE, usually about a second ago, as it takes some time for the signals to arrive, the fix to be calculated and the map updated. The navigation software anticipates that delay and forecasts where you SHOULD BE based on speed and direction you travelled a second ago. Normally, that forecast is correct, but sometimes it's not. If you are directed to take a turn and do not do so, it takes a second before the GPS fix shows you not there, and two fixes to figure out what direction/speed you did travel. So the map software assumes you took the turn, projects where you SHOULD BE if you did turn and has to correct when it figures out you didn't turn. That delay is why you see the map jump a bit at turns you ignore.

 

[pm-r]

...navigation suddenly became really accurate and GPS receivers for PDAs became a popular item. (Before smartphones for the young'uns.)

That's some nice interesting info Jake.
Back in those days, and even when in Canada in the costal marine boating world after they had installed Coastal Navigation Differential or whatever it was called, some acquaintances had installed this new thing called GPS on their 45 foot+ boat and were over full of confidence as they navigated through some narrow channels in the thick fog.

Skipper was rather surprised when there was a horrendous crunch as the yacht hit the rocks.

What they hadn't made any adjustment for was the fact that they had mounted the GPS antenna at the stern of the yacht, plus the fact that GPS wasn't quite as accurate in those days as it is now, even with the Coastal Navigation Differential stations enabled.



- Patrick
======

 

[MacInWin]

Patrick, I've heard other stories about GPS inaccuracy leading people into trouble. As an experiment, back in the mid-80's I set up a GPS in a fixed location and let it run for four hours, just to see how inaccurate it could be. At the time there were not as many satellites up, so when one of the birds "set" or got low in the sky, the atmospheric affects got pretty strange. Once I had 4 hours of data (fixes every second) I then plotted them all on a map. Most of the fixes were very close, within the 15 meter error then claimed. However, the worst fix was over a mile away. The fixes leading to that worst error showed the unit losing the position over about 15 seconds as one of the satellites set. Once the signal was lost, it snapped back to within the 15 meter circle. Today, with about 30 satellites up, there should always be 5 visible all over the surface of the earth, so the software can ignore the "Lone Ranger" that wants to wander off and use just the ones that agree pretty well. I haven't seen a wanderer in a long time.

I read the other day that Iran is blocking and inducing errors in the GPS signals in the strait of Hormuz to induce tankers to wander into their territorial waters so they can "arrest" the ship for violating their borders.

Lesson to be learned? That GPS, while really useful, needs to be checked with reality every once in a while.