Satnav with no contract?

kingarhu

I am coming to the end of my contract and have seen a new one I like, but I find the satnav on my current handset very useful. If I cancel the old contract (maybe swap it to pay as you go?) will I still be able to use the old phone to navigate?

gjchester

kingarhu wrote: »

I am coming to the end of my contract and have seen a new one I like, but I find the satnav on my current handset very useful. If I cancel the old contract (maybe swap it to pay as you go?) will I still be able to use the old phone to navigate?

Maybe.

The issue is most phone use data to do part of the initial GPS Lock and periodic checks. No Data means no assisted GPS and hence no locking on to the satellites.

grumbler

gjchester wrote: »

... No Data means no assisted GPS and hence no locking on to the satellites.

Do you not overestimate the importance of this? It will just take longer to lock. Most of satnav apps work without any data connection.

redux

gjchester wrote: »

Maybe.

The issue is most phone use data to do part of the initial GPS Lock and periodic checks. No Data means no assisted GPS and hence no locking on to the satellites.

It will still find the satelllites; it just takes slightly longer.

gjchester

grumbler wrote: »

Do you not overestimate the importance of this? It will just take longer to lock. Most of satnav apps work without any data connection.

redux wrote: »

It will still find the satelllites; it just takes slightly longer.

Yes I thought that too.

However for the last two weeks I've been on holiday in the USA with a iPhone and ipad both with GPS and sat nav software. Both locked on fine when we were in range of the Hotel Wifi but lost lock after a few miles, despite being in very wide flat area's so good views of the sky.

As soon as we got back in range of a Wifi connection they locked on again almost instantly.

d123

gjchester wrote: »

Yes I thought that too.

However for the last two weeks I've been on holiday in the USA with a iPhone and ipad both with GPS and sat nav software. Both locked on fine when we were in range of the Hotel Wifi but lost lock after a few miles, despite being in very wide flat area's so good views of the sky.

As soon as we got back in range of a Wifi connection they locked on again almost instantly.

Possibly a fault with your setup? Was the iPad a GSM model?

I often use an old iphone 4 without a sim card for TomTom. It works absolutely fine.

If the OP mentioned the actual satnav they are intending to use it would make the answers more relevant to their specific query.

gjchester

d123 wrote: »

Possibly a fault with your setup? Was the iPad a GSM model?

If it was one or the other that was at fault I'd agree, it was a GSM iPad so has the GPS chip over the just wifi models but we didn't have any sim card in it anyway.

Both are great here in the UK when we use a MiFi or a sim card when out and about. AT&T would happily have sold me a sim card and roaming data plan but only if I paid by US credit card..

redux

gjchester wrote: »

Yes I thought that too.

However for the last two weeks I've been on holiday in the USA with a iPhone and ipad both with GPS and sat nav software. Both locked on fine when we were in range of the Hotel Wifi but lost lock after a few miles, despite being in very wide flat area's so good views of the sky.

As soon as we got back in range of a Wifi connection they locked on again almost instantly.

I just took the SIM out of my Nokia phone, went outside, then started the Nokia Maps application. The settings were changed to not use wifi either

Within 2 minutes I had 6 or 7 satellites, with good strength, but not yet a fix. A couple of minutes more with no improvement.

I put the SIM back in, restarted, re-enabled assisted GPS and networks, and then had 11 satellites and a fix within about 40 seconds.

On a dedicated GPS, there is of course no network connection. It will remember its last position, and default assume to start with it's still there, and thus look for the relevant satellites; if it is there it will probably get a fixed position in 20 or 30 seconds. If you've meanwhile put it in your luggage and flown to somewhere else, or lost the time setting, then the initial fix will take longer because it may need to search for up to the whole constellation rather than start with the ones that would be in view at the last known place.

On a phone, I don't actually know whether the application saves the last known position. I assume perhaps not. That's what the network connection is for, just an initial approximation so it knows which satellites to look for. It shouldn't need any more data.

I came back indoors, where that mobile network is patchy, and sure enough it dropped signal. The satellites are also weaker, and I can't usually get an initial fix indoors, but it carried on this time once locked on.

In the log there are two mobile data sessions lasting 44 and 20 seconds, using 6 and 8 kilobytes.

I think it would have locked on eventually with no SIM, and then stayed locked on, and maybe achieved it slightly faster if I'd walked away from between houses and trees, but it is getting a bit chilly out there so I didn't wait.

I used this for driving back across Poland, with a Lithuanian SIM in it which apparently had no roaming, so I'm sure that maps application can gain an initial fix and navigate for hours with no mobile network at all.

I can't explain why yours are dropping out. Maybe it's to do with the way the application is written, that perhaps it wants to correlate network fixes more often even though the satellites are much more accurate. I'd be a bit surprised.

gjchester

redux wrote: »

I just took the SIM out of my Nokia phone, went outside, then started the Nokia Maps application. The settings were changed to not use wifi either

Could be that mine are both Apple and it's how Apple allow GPS access.

Eitherway it's still a Maybe as to what the OP has and how it works.

I've got a "proper" GPS in the car that pretty much never gets used here as I use the iPhone, I know GPS can work without a network connection but Apples don't appear to do so well.

d123

gjchester wrote: »

Could be that mine are both Apple and it's how Apple allow GPS access.

It's not an Apple problem as I've just tested out using TomTom in an iPhone 4 with NO SIM card and it works perfectly.

From cold start to GPS acquisition was around 15 seconds, tracks perfectly and routing directions all work as they should. This was over a route of around 50 miles through both urban and rural areas.

What satnav app were you using? It can only be a problem with your app, hardware or settings.

gjchester

d123 wrote: »

What satnav app were you using? It can only be a problem with your app, hardware or settings.

Ipad 1 and Iphone 5, with Nav Free USA.

Both lost lock after about a mile without a data connection.