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GPS not working when phone has No Service


Nic Hubbard

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I have had two users report this issue that their phones were not able to find their current location when in an area with No Service. Switching to another app worked correctly and found their location.

Has anyone else had this issue?

I tried to reproduce this issue on a hike up Mt. St. Helens with No Service but Cachly worked perfectly the whole time and there were no issues with GPS.

Just trying to track this bug down...

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Around my home location (Northern NJ) it's hard not to have service anywhere. When I was traveling in Nevada, Utah, Colorado and New Mexico for 2 weeks the 2nd half of June, I experienced extended periods of no cell service and didn't have an issue whenever using Cachly. 

Do these users experience the same behavior if they put their phone in airplane mode? 

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1 hour ago, Bolling said:

Could turning off the Compass Calibration possibly cause this issue? I wouldn't think so but it's the only Cachly setting I can think of that might be different than their other apps. 

I would't think this would affect anything unless there was a deep bug in iOS. That setting only changes a true/false value in the compass API for iOS.

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Hi Nic,

We were down in Lake Padden Park near Bellingham yesterday.

I was using Cachly both in Live & Offline.  Things were working just fine until we got into a "No Service" area.  Cachly blew its brains out.  The map display showed a bunch of caches to the West (none of them in the area that we were), and no caches where we were.  Switched to List mode, and could not locate the cache we'd just found to mark it as found.  I played around with it for about 5 minutes, and finally, my wife told me to get my butt in gear.

I switched to my old geocaching app, Geosphere, and things were just fine.

As service was intermittent throughout the day, I just continued using Geosphere.  Logged the first 8 caches (for later upload) in Cachly, and the remainder 13 in Geosphere.

I didn't think about it at the time and didn't take any screen shots.

Using an iPhone 5S running 9.3.5

Cheers,

Mark

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@Sailaboat - Just noodling what you reported, I wonder if your phone at the time was using the cell towers for location and not using the GPS. When you lost service, the phone/app didn't have the GPS signal. I know you indicated you then launched the "G" app and it worked, but you didn't report if you closed down Cachly and relaunched it during the time you were playing with it? 

Did you try going to airplane mode for a minute and then turn off airplane mode? I sometimes need to do this with Waze when it gets whacked out and closing/relaunching doesn't help. 

I travelled 380 miles (611 km) yesterday and used cachly & waze for 12 hours and even the official geocaching app at times for a live view if I went someplace I didn't originally plan. The only app I had an issue with was Waze twice when it wouldn't calc a route or showed "searching for network..." when I had a full cell signal and closing it, going to airplane mode for 1 minute and then relaunching it resolved the issue. Just closing and relaunching didn't help. 

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Hey Team DEMP,

So before I jump into a reply, I'll take a complete lateral shift over the use of the verb "noodling".  My parents used that term all throughout my life.  It was an indicator of just pursuing activities at your own pace with no overall plan, just enjoying life.  Then I saw a PBS segment about "noodling" in the Southern East rivers of the U.S.  These guys called the activity of jumping out of a skiff in very turbid rivers swimming along the shore, feeling your way with your hands, and finding an underwater hole, shoving your hand in.  If there was a large catfish in the hole it would bite onto your hand, you'd pull out your hand and flip the catfish into the skiff => noodling!!!!

Anyway, I digress.

As this was the first time I'd experienced this I can reply that "No" I didn't try any of your work arounds.  I'm a die hard "G" fan who has come to the recognition that the "G" developer has left the building and time to move on.  Mark me as a Cachly newbie, still struggling with some of the features, but committed to changing gears and saying good bye to "G".  Cachly is sure a clunker when it comes to loading offline lists, but I digress.

I have absolutely no time for the official app, don't even have it installed.

Should I experience this again, I'll try the work arounds you suggest, especially the "airplane mode" trick.

Thanks,

Sailaboat

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2 minutes ago, Sailaboat said:

Then I saw a PBS segment about "noodling" in the Southern East rivers of the U.S.  These guys called the activity of jumping out of a skiff in very turbid rivers swimming along the shore, feeling your way with your hands, and finding an underwater hole, shoving your hand in.  If there was a large catfish in the hole it would bite onto your hand, you'd pull out your hand and flip the catfish into the skiff => noodling!!!!

I've seen that show too on catfish noodling with your arm in a hole - no thanks!. :-D 

Maybe Nic or others have some ideas what might have occurred and have additional suggestions should you experience it again. 

When the diehard "G" users come to Cachly, they usually bring a flurry of how things work in the app they've used for years. Just need to re-learn how to do things in Cachly or alter your approach to leverage what is supported. I never used the "G" app as I got started in 2003 are there were no apps and after taking a many year break from caching and checking the options, "G" was already not being supported so I didn't even give it a test run. I have popped over from time to time to see what "G" users are saying in their forums about the app as well as Cachly.  I couldn't use the official app because at the time it didn't support showing corrected coords so it was useless when attempting solved puzzles but I sometimes use it for any messaging which isn't available to 3rd parties and if I want to run a live view loading in hundreds/thousands of caches vs decrementing against my daily limit by repeating the load process in Cachly's live view.

Good luck! 

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2 hours ago, Sailaboat said:

The map display showed a bunch of caches to the West (none of them in the area that we were), and no caches where we were.  Switched to List mode, and could not locate the cache we'd just found to mark it as found.  I played around with it for about 5 minutes, and finally, my wife told me to get my butt in gear.

What was the issue here? Had you saved caches offline?

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1 hour ago, Sailaboat said:

Should I experience this again, I'll try the work arounds you suggest, especially the "airplane mode" trick.

You shouldn't have to use any tricks to keep GPS working. Was that the issue is that GPS stopped working and you couldn't see your current location?

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Hi Nic,

With respect to "clunker" I believe Cachly's data base is a wipe and reload.  Whereas true databases load just the delta's.  Geosphere loads the same caches in less than 20 seconds, to an existing database.  Cachly, I just put the phone down and come back after 20 minutes to see how its doing.

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When you say "loading offline lists" do you mean opening an existing one or do you mean creating one from the results of a search or an import?

Geosphere does a full cache load on searches and puts all search results in the DB. Therefore, adding search results to an offline group is nearly instantaneous as all the data is already local in the DB. Cachly loads light search results and search results are not put in the DB. When you save to offline, each cache then has to be fetched in full via the API. I don't know if each is fetched with a separate request? If so, that could have a lot more overhead than a request for a batch of results like the search with full results done by G. Nic can comment on how it is done. 

 

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13 hours ago, Sailaboat said:

With respect to "clunker" I believe Cachly's data base is a wipe and reload.  Whereas true databases load just the delta's.  Geosphere loads the same caches in less than 20 seconds, to an existing database.  Cachly, I just put the phone down and come back after 20 minutes to see how its doing.

I am not sure what you are saying here. What action are you doing that takes 20 minutes?

Cachly does use a true database. If you are not happy how it works please let me know how we can make it better.

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11 hours ago, rragan said:

Cachly loads light search results and search results are not put in the DB. When you save to offline, each cache then has to be fetched in full via the API. I don't know if each is fetched with a separate request? If so, that could have a lot more overhead than a request for a batch of results like the search with full results done by G. Nic can comment on how it is done. 

When you save offline, you can save Lite caches and it will save those instantaneous since it already has that data from the search. If you want full data then that has to be requested from the server, 50 caches per request since that is the max the API allows. This is the same limitation that any other API app has.

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Going back to the subject of this post.  Should I experience the issue with the GPS not working in a "no service" area is there anything you recommend I should try?

I see that as of iOS 8.3 that airplane mode doesn't affect the GPS, so switching it on shouldn't do anything for the Cachly app.

It doesn't sound like it's pervasive, and I'm not sure when I'll be wandering around in a "no service" zone again.

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2 hours ago, Sailaboat said:

Going back to the subject of this post.  Should I experience the issue with the GPS not working in a "no service" area is there anything you recommend I should try?

I see that as of iOS 8.3 that airplane mode doesn't affect the GPS, so switching it on shouldn't do anything for the Cachly app.

It doesn't sound like it's pervasive, and I'm not sure when I'll be wandering around in a "no service" zone again.

I have tried to replicate this many times, including today driving from an area with excellent service, to the National Forest with no service. Cachly had no issues with following my location. I have also tested this hundreds of times over the last 5 years, so it is for sure a tricky thing to debug.

I think the one thing to try is to quit Cachly. Possibly if there is a Location Services bug in iOS that would help it to start using GPS rather than just cell tower triangulation.

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I experienced this today, a couple of times.

 

I was in a no service area when I launched cachly and I could not get a position fix, may would not load (although I have off-line maps of the area). I launched another of-line map app (Pocket Earth) and it gave me my position. Back to cachly and no potion. I tried an offline list, still no position.  A few minutes later, I came into cell coverage and bam, cachly gave me my position.

Later I went out of cell range (no service) and cachly seemed to give me my position, but cachly had been running in the background. I ended the app and restarted, again, no position.

Later I was in poor cell coverage, I launched cachly and I could keep touching the triangle in the lower right corner (localization) and it would not give me a position. I was driving home, still tapping the triangle. When I arrived home as soon as my phone locked onto my home WiFi, bam, I had a position.

The one clue I have is it seems to fail when in a poor/no coverage area and you do a fresh launch of cachly.

Screen shot 1 and 2 are in the no service/poor service area. Position would not show despite taping the localization button, lower right.

Screenshot 3 is when I got in better cell coverage and I was then able to get a position.

I'm running an iPhone 6S.

 

IMG_9862.PNG

IMG_9863.PNG

 

IMG_9864.PNG

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It is my experience that Cachly will not get a position when there is no map. 

I was in an area with poor coverage and could not get a position but it was because I was on Google maps which could not load due to the coverage. As soon as I switched to the offline map of the area location worked. 

Both images above have no map. 

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9 hours ago, ChrisDen said:

It is my experience that Cachly will not get a position when there is no map. 

I was in an area with poor coverage and could not get a position but it was because I was on Google maps which could not load due to the coverage. As soon as I switched to the offline map of the area location worked. 

This should have no bearing on location services in iOS unless there is a deep bug in iOS that is not from Cachly. I still have not experienced this issue myself. This weekend I was camping with no service for 3 days and we able to get my location in Cachly the entire time. 

Absolutely not doubting the issue is happening for some users, but I cannot yet pinpoint the cause.

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1 hour ago, Nic Hubbard said:

Were you moving or stationary when you were not getting location updates?

In both cases I was moving (in my car).

I'll be back in the same area today and will try what ChrisDen said in that Cachly will not get a position when there is no map. I'll bring up the offline map ad see if I get the fix then.

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5 minutes ago, Team DEMP said:

I ran a test by setting Cachly to use an online map and closing the app. I put the phone in airplane mode and launched Cachly. The map didn't load of course but everything else seemed fine with my offline lists. 

I have tested this way probably hundreds to thousands of times over the years. I do not think it can accurately replicate the issue here.

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43 minutes ago, Highlands_guy said:

I'll be back in the same area today and will try what ChrisDen said in that Cachly will not get a position when there is no map. I'll bring up the offline map ad see if I get the fix then.

Just came back from getting my cache and this time I had no issue at all getting a position with Cachly. It worked every time I ran the app in every scenario I tried.

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Something to keep in mind is the iPhone uses Assisted GPS:  if you have a network connection it can take up to 30 seconds to download satellite data before your location can be calculated.  Without a network connection this maximum increases to 10+ minutes.

https://en.wikipedia.org/wiki/Assisted_GPS

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I ran into this issue a couple of times in the last few days. I am traveling in a foreign country (Peru) with expensive call rates and no data plan, so I went into airplane mode to save some batterry. As soon as I was connected to the hotel Wifi the phone got my location.

This behavior can be explained very well by the Assisted GPS. I will keep an eye on that.

Do you know whether the cell towers provide this information even if I disabled mobile data? 

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2 minutes ago, ploppy said:

Do you know whether the cell towers provide this information even if I disabled mobile data? 

This I am not sure of.

When out in the field did you wait for an extended period of time to see if a location was received? If not, how long did you wait?

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1 hour ago, Nic Hubbard said:

This I am not sure of.

When out in the field did you wait for an extended period of time to see if a location was received? If not, how long did you wait?

I did not wait the 12.5 minutes that are the maximum to receive that information via GPS. Maybe a minute or two...

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  • 3 weeks later...

I just returned from a 2 week trip through 8 states and had this problem quite a bit.  When I had no service, cachly wouldn't work.  Seems like it got worse as the trip went on, but could be that some areas were more prone to no service.  I also have Sprint, which is another problem.

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2 minutes ago, Tim said:

Maybe something with the last update?

No. Nothing has changed with our location services code.

We are working on this bug with Apple. It seems there is a point where assisted GPS is trying to use GPS and cell tower triangulation and when there is no service or spotty it doesn't do well.

What iOS and phone version please?

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5 minutes ago, Nic Hubbard said:

No. Nothing has changed with our location services code.

We are working on this bug with Apple. It seems there is a point where assisted GPS is trying to use GPS and cell tower triangulation and when there is no service or spotty it doesn't do well.

What iOS and phone version please?

IPhone 6S  iso 10.3.3

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I ran Cachly in Airplane mode on a small plane flight from Victoria to Seattle and used the GPS to track the flight path and ground features all the way. I'm sure there were no cell towers much of the way and airplane mode disabled the cell radio anyway. Other than a slight lag discrepancy between what the the position on the offline map showed and what was right under the plane, I never saw any problem. 

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30 minutes ago, rragan said:

I ran Cachly in Airplane mode on a small plane flight from Victoria to Seattle and used the GPS to track the flight path and ground features all the way. I'm sure there were no cell towers much of the way and airplane mode disabled the cell radio anyway. Other than a slight lag discrepancy between what the the position on the offline map showed and what was right under the plane, I never saw any problem. 

Correct. The problem is extremely hard to replicate. It does not happen in Airplane mode. It seems, based on a few users, that it happens when there is spotty data and it drops to No Service. 

I cannot replicate the issue, so it is very hard to try to figure out the cause.

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