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Is the A-GPS assisted by the datanetwork, or the standard network?

S

stofferdk

macrumors regular
Original poster
Jul 22, 2007
200
0
Copenhagen, Denmark
Dear MacRumours,

When I use my beloved Navigon app, I suppose it lets the GPS get assisted. So, my question is - does the GPS get assisted by the datanetwork (2G or 3G), or the standard network? Or have I misunderstood how it works?!

I am asking because I wish to travel with my iPhone and Navigon through Europe. As I will not bring my simcard (no roaming charges for me), I thought about just buying a prepaid simcard in each country, just to get a signal.

Will this signal be enough for the GPS to be assisted, or will I need to get a prepaid dataplan also?

Thanks!
 
The iPod Touch gives a rough indication of location without using GPS but by using the cell tower triangulation.... I would assume the iPhone uses the same method and so no sim card would be needed for the A-GPS to work.
 
The Iphone GPS does not need data unless you are using the Google maps or any app that needs data. If Navigon has all the maps installed in the iphone you are good to go. You can test it now without going to other country. Removed your sim and try running Navigon if it will work.
 
Cell Tower Triangulation and Assisted GPS are two completely different things.

Cell Tower Triangulation is where the phone can work out where you are by looking at the relative signal strengths of a few cell towers. This is not GPS.

GPS uses a network of satellites to work out where you are. This doesn't require any form of network connection, but can be slow (take a couple of minutes until it's up and running).

A-GPS, or Assisted GPS, uses an internet connection to download information about where the satellites are likely to be (approximately), before using GPS to work out where you are. That internet connection can be wifi, 3G, or anything. If the internet connection is not present, the system falls back on standard GPS.

One further point: prepaid SIM cards (at least in Britain) will probably allow you to access the 3G data network. For example, Orange charge £2/day, just taken off your normal credit, so no special plan needed. This may be similar in the rest of Europe.

Amorya
 
Thank you for your replies! Most helpful.

Fact is for me, that Navigon regretfully is almost useless without sim card. The GPS never really seems to get a lock. I tried a few times, and when it finally gets a lock, or loses track fast when driving.

My concern is I really need those prepaid sim cards with data access
 
Call me crazy, but I noticed having WIFI turned on also improves the GPS accuracy in the turn-by-turn apps.
 
Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16)

pauliphone said:
The iPod Touch gives a rough indication of location without using GPS but by using the cell tower triangulation.... I would assume the iPhone uses the same method and so no sim card would be needed for the A-GPS to work.
Click to expand...

No it doesn't.

It uses wifi hotspot locations.

The iPod touch has no capability to recieve any kind of cell phone tower signals.
 
well, I still seek a definitive answer regarding the dataconnection.

When I travel Europe, will having a cellconnection be enough for the GPS to get assisted? Or will I need a datacard?

I really hope I wont need to buy those expensive prepaid datacards
 
stofferdk said:
well, I still seek a definitive answer regarding the dataconnection.

When I travel Europe, will having a cellconnection be enough for the GPS to get assisted?
Or will I need a datacard?

I really hope I wont need to buy those expensive prepaid datacards
Click to expand...


You do not need a connection at all for gps to work on your Europe trip.

Also if you have roaming turned off there is no data connection avalible for your iPhone to use.
 
Gav2k said:
You do not need a connection at all for gps to work on your Europe trip.

Also if you have roaming turned off there is no data connection avalible for your iPhone to use.
Click to expand...

but when I have no cellconnection in my home country, the GPS never seems to work properly :/

Guess ill do some testing with data off
 
stofferdk said:
but when I have no cellconnection in my home country, the GPS never seems to work properly :/

Guess ill do some testing with data off
Click to expand...

are you placing it so it has direct line of sight with the sky?
 
stofferdk said:
well, I still seek a definitive answer regarding the dataconnection.

When I travel Europe, will having a cellconnection be enough for the GPS to get assisted? Or will I need a datacard?

I really hope I wont need to buy those expensive prepaid datacards
Click to expand...

To get Assisted GPS, you will need a data card.

To get Cell Tower Triangulation, I believe you don't need a data card, although I'm not 100% sure.

Amorya
 
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