[praful]

Originally Posted by skdking

How does one know which phones also have built-in GPS receiver?

Don't all high end phones with GPS (Not-Only Assisted GPS) come with GPS receiver.

You have me worried there. I bought an E72 a week back. Is it likely that it also does not have GPS receiver?

E 72 has a A GPS!

I am not sure, but most of Nokia's phones are A-GPS variety. Only a few come with a proper GPS receiver. But even, a fix to about 600mtrs is fairly accurate to help you find your way.

[ampere]

Originally Posted by Technocrat

@BB - damn you guys get GPRS for so cheap we have Rs399/500mb or 499/1gb options with Idea.

Airtel has 399/100Mb. Not sure how the roaming charges add up. Having said that its not the price alone. You don't want to depend on GPRS, but the offline mode.

Meanwhile can some please take a class on A-GPS versus GPS. I know, A-GPS is assisted, but what I can't understand is that, does it mean that there is no GPS at all, and all the phone does is GPS correction? Or is it that one needs to use the A-GPS in a non-assisted mode to avoid security concerns.

Here is the Wikipedia link for A-GPS: http://en.wikipedia.org/wiki/Assisted_GPS

[bblost]

Originally Posted by skdking

How does one know which phones also have built-in GPS receiver?

Don't all high end phones with GPS (Not-Only Assisted GPS) come with GPS receiver.

You have me worried there. I bought an E72 a week back. Is it likely that it also does not have GPS receiver?

GSMArena.com - GSM phone reviews, news, opinions, votes, manuals and more...

That is the best place for mobile config.

Next only to our own Mobile phone thread.


Also my phone has GPS in it.
Was testing without GPS on as I was inside a building.

[praful]

Originally Posted by ampere

Meanwhile can some please take a class on A-GPS versus GPS. I know, A-GPS is assisted, but what I can't understand is that, does it mean that there is no GPS at all, and all the phone does is GPS correction? Or is it that one needs to use the A-GPS in a non-assisted mode to avoid security concerns.

Here is the Wikipedia link for A-GPS: Assisted GPS - Wikipedia, the free encyclopedia

A GPS is more of a pseudo GPS, it uses the location of the cell phone towers closest to you and triangulates your position based on that. For that reason A-GPS is not very very accurate. Don't go by the word 'Assisted', a phone with A GPS usually does not have GPS receiver.

On the other hand, a phone with a independent GPS receiver, connects on its own to GPS satellites and gets an almost exact fix of your position. Thats why a A GPS would most prolly work even inside a building where you are getting mobile signal.

In places with not network, your A GPS will fail to work.

[ampere]

Originally Posted by praful

A GPS is more of a pseudo GPS, it uses the location of the cell phone towers closest to you and triangulates your position based on that. For that reason A-GPS is not very very accurate. Don't go by the word 'Assisted', a phone with A GPS usually does not have GPS receiver.

On the other hand, a phone with a independent GPS receiver, connects on its own to GPS satellites and gets an almost exact fix of your position.

In places with not network, your A GPS will fail to work.

That explains it. Thanks.

I was looking for a real GPS. So which is the cheapest Nokia, which has a "GPS" and not "A-GPS"? Also how non-Nokia phones perform on this front? Can Garmin S/W be loaded on them? Or re-phrase the question, how do we the offline map mode on these phones?

[praful]

Originally Posted by ampere

That explains it. Thanks.

I was looking for a real GPS. So which is the cheapest Nokia, which has a "GPS" and not "A-GPS"? Also how non-Nokia phones perform on this front? Can Garmin S/W be loaded on them? Or re-phrase the question, how do we the offline map mode on these phones?

Not sure, don't have much of idea about Nokia phone coz symbian did not appeal to me much!

Like it has been said before, you can MGmaps, they have all the maps offline and you can get you position on that map if your phone is AGPS/GPS enabled.

Since we are on the topic of GPS on phones, anyone have any idea of a s/w that has offline maps+GPS positioning on offline maps+GPS track creation ability? I am yet to find something that does all three together.

PS: This would be for a WinMo!

[Technocrat]

Originally Posted by praful

A GPS is more of a pseudo GPS, it uses the location of the cell phone towers closest to you and triangulates your position based on that. For that reason A-GPS is not very very accurate. Don't go by the word 'Assisted', a phone with A GPS usually does not have GPS receiver.

Are you sure about this? From what I have heard & read A-GPS is faster to lock than just GPS because of triangulation. At the end of the day both need GPS receivers for locking on to the satellites.

Here is what Wiki Says

Assisted GPS, generally abbreviated as A-GPS, is a system which can improve the startup performance of a GPS satellite-based positioning system. It is used extensively with GPS-capable cellular phones as its development was accelerated by the U.S. FCC's 911 mandate making the location of a cell phone available to emergency call dispatchers.

GPS operation uses radio signals from satellites. In very poor signal conditions, for example in a city, these signals may suffer multipath where signals bounce confusingly off buildings, or be weakened by passing through walls or tree cover. When first turned on in these conditions, some non-assisted GPS navigation devices may not be able to work out a position due to the fragmentary signal, rendering them unable to function until a clear signal can be received continuously for up to 40 seconds (the time needed to download the GPS ephemeris).

An Assisted GPS system can address these problems by using data available from a network.

[ampere]

Originally Posted by Technocrat

Are you sure about this? From what I have heard & read A-GPS is faster to lock than just GPS because of triangulation. At the end of the day both need GPS receivers for locking on to the satellites.

Here is what Wiki Says

I know for sure that the cell phone location based on 3-Tower exists in many blackberry handsets, which works over on top of Google Maps.
But I am not sure if that is what is A-GPS.

[clevermax]

I am not sure about the term A-GPS. My phone don't have GPS but it locates my position in a ~2Kms radius in google maps - Obviously using the cell phone tower info. No GPS stuff at all.

[Technocrat]

@clever - Exactly, the cellphone location identification is done using triangulation (Link 1, Link 2) & this happens even in non GPS/A-GPS phones.

@ampere - no this is not called A-GPS

There are a few versions on Symbian which do not support this & sadly N72 is one of them :(

[bblost]

I use the gps in my phone on a fairly regular basis. It has a screen that will show the number of satellites its locked on and lat-long-altitude and speed.

If I am in a open area like a playground. It will get a lock on 7-9 satellites within 20 seconds. Get the lat and long co-ord within 40 seconds. It will use that to get the bearing on the map.

If I am inside a building, it will never get a lock unless I am standing in a balcony.

If I am around tall buildings it takes sometimes close to 5 mins before it gets a lock.
Between tall building, never.

A-GPS does not depend on the sat. It gets its signal from cellphone towers. So if you have a network available it will get a lock.

So the idea is, use A-GPS to know where you are instantly.
Use GPS to find it more accurately but will take more time.

The maps can be displayed from either across the network i.e. download in real time.
OR
stored in internal memory

[ampere]

That brings us back to the original question.
What is the difference between GPS and A-GPS in a layman's term?

[Technocrat]

Simply put a device with a GPS receiver will work even if there is no network while the one which does not have it will not.

[praful]

Originally Posted by Technocrat

Are you sure about this? From what I have heard & read A-GPS is faster to lock than just GPS because of triangulation. At the end of the day both need GPS receivers for locking on to the satellites.

With a AGPS you are already connected to the Mobile tower and just the information needs to be downloaded, hence it is faster to get a lock.

With a standalone it first connects to the satellites and then downloads the location data and is slower. But it is far far more accurate than a AGPS. Some phone have both AGPS and GPS, i.e. they get a initial lock using AGPS and then further get a accurate lock via the GPS receiver.

Originally Posted by ampere

That brings us back to the original question.
What is the difference between GPS and A-GPS in a layman's term?

Layman's terms definition was already posted earlier. Do you want to make it even more 'layed'?

[Technocrat]

Praful by that definition phones with AGPS would not latch on to the satellites right?

Can any Nokia 5230 owners confirm this i.e. whether it uses satellites for navigation or not?