why doesn't gps work without phone signal

What's OP? Anybody knows whether I can find coordinates on the ground with I Phone Plus? I have the coordinates of a tract of land in Texas. I need to pinpoint these coordinates on the ground. (Or at least one of them). Can the I Phone be of help?

Jalisco15 wrote:

What's OP? Anybody knows whether I can find coordinates on the ground with I Phone Plus? I have the coordinates of a tract of land in Texas. I need to pinpoint these coordinates on the ground. (Or at least one of them). Can the I Phone be of help?

You will get more and better help if you start your own thread rather than adding on to an old one about a somewhat different issue.

OP = original poster, the person who started the thread.

The Compass app displays the GPS coordinates of the phone's location. This is good enough for casual use, but is not considered a legal description of real property. For that you need to hire a licensed surveyor.

I was quoted $5,000 for a surveyor... cannot afford it. Legal description of the property is on the purchase documents. My issue is to match as close as possible the coordinates on these documents with the coordinates on the ground. From there, I will assume 50 feet of possible error when building my house. Moreover, with the approximate ccoordinates, I will have a chance to locate the original survey markers. If I find one of the many, I will be even more reassured. I was to acquire a Garmin device, but Apple compass might save me money. (I read that apple can read GPS and GLO satellites, giving more precision to the readings).

Thank you for your comment.

Jalisco15 wrote:

Thaank you for telling me. By the way, Apple chat has helped me to find a solution for my querry.. just download the Compass.

Compass is not an app that you download (unless you had deleted it from your phone in the past). It's one of the pre-installed apps. I hope you didn't download anything you had to pay for.

If you want something more sophisticated than the Compass app there is an app called GPS Diagnostic. In addition to your position, it will tell you how many satellites are being received, their signal strength, and, most important, the accuracy of the reported position.

You scared me.. Apple technician told me to write 'compass' on search and a yellow black thing came on. It said: Install, I did; no payment was mentioned. Apple tech told me on a chat that's the thing... It looked like a real compass and the coordinates were underneath...

I am not sure. I guess I wrote Compas (as asvised by apple agent) and got this yellowish thing on brown background.

I got the chat case number so, in case ot trouble, I can go back to them). Thank you Sir. I will drive now some ten miles and see my coordinates there...

What app were you using? I'm thinking that the app you were using requires a data connection to refresh the maps and that when it is unable to load maps it stops working. The GPS should work without a data connection.

this seems to be the normal operating mode on the iphone.

with airplane mode on i cannot get my gps position from maps, tomtom iphone software or navigon iphone software.

with wifi turned off and the 3g data turned off i am able to get a gps lock

so it seems to be normal that you need a valid phone signal in order to get a gps lock

Airplane mode turns off all iPhone radios - cell/data, bluetooth, wi-fi, and GPS.

You do not need cellular reception to get a GPS lock - the iPhone includes a dedicated GPS receiver. If you are using an app that requires internet access to download maps data, you need an internet connection via an available wi-fi network or via the cellular network, but not for GPS reception alone.

okay i think i figured this one out

yes it is true that the iphone has a dedicated gps recevier and it is also true that some navigation apps like the standard maps app and the garmin navigator need some kind of connection to fetch the map ..

but the gps recevier is a AGPS receiver, this means it has a standard gps receiver but it also uses the cell towers to assist the gps lock and to speed up the locking process. without some kind of conenction to the tower or a wifi connection, a full gps lock can realistically can take 15 or 20 minutes to get, if you do not know where the satellties are. the gps satellites only broadcast once every like 30 seconds? and with 30 of them it means it can take 15 mintues to get them all

the iphone uses the towers and wifi connection to download information on where the satellites are and then looks for them to speed up the gps locking.

so to the original posters question to why his iphone cannot get a gps lock. well yes you might need a connection to get the map, but if you want to get a lock without a cell phone connection / wifi connection to assist you, you just need to wait 5-15 minutes to get it

and to answer why the standalone gps can keep going could be because some gps units keep 3 or more days of gps coordinates. tomtom calls this feature of obtaining gps corrdinates to speed up gps locking, GPS quick fix.

there are also some chipsets like the sirfstar iii that are known to speed up gps lockng

I believe GPS satellites transmit continuos signals and you only need to find 4 satellites to find your location. As you said, it can take several minutes to get a fix without a cell signal. But if the OP had a GPS fix, and lost the cell signal the GPS should still work unless one or more GPS signals was lost. The OP could have lost the cell signal and one or more GPS signals. Since the handheld GPS is designed to receive GPS signals it may not have lost any GPS signals while the iPhone is designed to be a cell phone might have.

I live in Japan ,they Apple and Carriers do not want iPhone users to use GPS alone because of sensitivity of knowing where you are some Apps are used for spying on users too.Fo example I went into a small thicketed forest on outer area of the city. I could not see my way so I used my Map but it did not position me it was on but no 3 /4 G or LTE WiFi was on Sim card in Cellular and I was 80 metres from the place I was going to but I was off the road ,at that place the map always works and if you walk on the road then it works I was just testing to see if it would show me.

I called Apple Japan Call centre and he would not say yes or no when I asked him can we use GPS if I do not have GPS and he was not happy being asked the questions I went in to details 1 hour on this post about the use GPS.

It seems they are selling something that we can not use it is about who is tracking who and where are you going and we must know where you are going but we do not want you to know that we know ! because we can find out that we are being tracked because they can switch it off when we go off the road.

It is about them knowing where we are and not where you knowing where you are.

sheffi wrote:

It seems they are selling something that we can not use it is about who is tracking who and where are you going and we must know where you are going but we do not want you to know that we know ! because we can find out that we are being tracked because they can switch it off when we go off the road.

It is about them knowing where we are and not where you knowing where you are.

Your post makes very little sense. It sounds a bit paranoid. If you have an actual technical support question, you should start your own post rather than resurrecting a post that's been dormant for almost four years.