iPad 3G question

[Mike_73]

No problems with connections to the internet with my wifi only ipad. But I wish they would have had a model sans 3G but with GPS.

Is this "bundled" within the hardware???

[Maggie Leung]

Originally Posted by Mike_73

No problems with connections to the internet with my wifi only ipad. But I wish they would have had a model sans 3G but with GPS.

Is this "bundled" within the hardware???

Post No. 14 by Rob_E explains why no GPS with wi-fi.

[kjk]

Originally Posted by Mike_73

No problems with connections to the internet with my wifi only ipad. But I wish they would have had a model sans 3G but with GPS.

Is this "bundled" within the hardware???

According to this teardown, the GPS chipset is mounted on the same daughterboard as the 3G chipset (a board the wifi model doesn't have), and it is a separate chipset (and antenna, actually) from the 3G chipset...if that is what you mean by "bundled"?

[Mike_73]

Exactly what I meant. Thanks kjk.
I still wish there would have been the GPS without the 3G. I mean I don't necessarily need GPS, but I bet it would have been fun playing with it.

[kjk]

Originally Posted by Mike_73

Exactly what I meant. Thanks kjk.
I still wish there would have been the GPS without the 3G. I mean I don't necessarily need GPS, but I bet it would have been fun playing with it.

You know, with all this location-based stuff coming out, I will not be surprised if the next gen iPod Touch/iPad wifi/even Macbooks all start including GPS. It is a pretty cool thing to play with. (Compass too!)

[Mike_73]

Well, I hope they won't release a next gen ipad with such features this year. My wife will kill me if I buy another toy like this this year .

On the other side, I was already thinking about a canon 7D for more than double the price of my current iPad

[Maggie Leung]

How is GPS going to work with wi-fi? Won't you essentially get a guesstimate of where you are, even if you can pick up a wi-fi signal?

[kjk]

Originally Posted by Maggie Leung

How is GPS going to work with wi-fi? Won't you essentially get a guesstimate of where you are, even if you can pick up a wi-fi signal?

Maggie, GPS can work totally separately from wi-fi (or 3G for that matter).

[Maggie Leung]

Originally Posted by kjk

Maggie, GPS can work totally separately from wi-fi (or 3G for that matter). If you had access to maps on your device, for example (instead of needing to download them on the fly), GPS alone could locate you precisely.

Not understanding how that works. Can't you already load maps on an iPad with only wi-fi? If I turn off the connection, how does the satellite know where I am? How does the communication happen?

[kjk]

Originally Posted by Maggie Leung

Not understanding how that works. Can't you already load maps on an iPad with only wi-fi? If I turn off the connection, how does the satellite know where I am? How does the communication happen?

The GPS chip reads its location from the GPS satellites. It can't *send* its position to others without a cellular connection, but it can locate itself on a map you have on your device.

[Rob_E]

Originally Posted by Maggie Leung

How is GPS going to work with wi-fi? Won't you essentially get a guesstimate of where you are, even if you can pick up a wi-fi signal?

That depends on what you mean. Do you mean "How is a GPS chip going to work with wifi?" Or do you mean, "How is a system going to use wifi to find your location?" Or do you mean something else.

The GPS chip is independent of wifi, and, while it may be a part of the same unit as the 3G chip, it is technically separate from that, too. You can get GPS units that have neither wifi nor cell phone chips. The GPS chip does it all on its own.

You can get an approximation of your location without a GPS chip using only cell signals (if you have a cell phone chip) or only wifi. Wifi, I believe, will look at local wifi networks and compares them to some database or some ip-based naming structure to place them geographically. It's far from perfect, but on my wifi-only iPod touch it usually places me within a city block of where I am. But sometimes it can't find me at all or puts me in a whole other state, so in the best case it's not as precise as a GPS, and in a worse case it's useless. But more often then not it does pretty good if you're connected to a wifi network. Cell phones and other devices that use the cell phone network can do something similar by reporting how strong the signal is and what tower it's connected through. If it's in range of more than one tower, your position can be triangulated. If not, it just has to guess that you're within X feet/miles of a given tower.

My understanding of the iPad/iPhone is that they use a combination of GPS and cell towers. The cell towers give it a general position, which lets the GPS unit eliminate a lot of possibilities and narrow down your exact(ish) location more quickly.

So basically you can use any of the three (GPS, wifi, or cell) to find your location, but they vary in precision and reliability.

[BenG]

The device picks up signals from 3 or more satellites and measures how far away you sre from each satellite by how long it takes the signal to get to you. It uses that information to triangulate your position.

[Maggie Leung]

Originally Posted by Rob_E

That depends on what you mean. Do you mean "How is a GPS chip going to work with wifi?" Or do you mean, "How is a system going to use wifi to find your location?" Or do you mean something else.

The GPS chip is independent of wifi, and, while it may be a part of the same unit as the 3G chip, it is technically separate from that, too. You can get GPS units that have neither wifi nor cell phone chips. The GPS chip does it all on its own.

You can get an approximation of your location without a GPS chip using only cell signals (if you have a cell phone chip) or only wifi. Wifi, I believe, will look at local wifi networks and compares them to some database or some ip-based naming structure to place them geographically. It's far from perfect, but on my wifi-only iPod touch it usually places me within a city block of where I am. But sometimes it can't find me at all or puts me in a whole other state, so in the best case it's not as precise as a GPS, and in a worse case it's useless. But more often then not it does pretty good if you're connected to a wifi network. Cell phones and other devices that use the cell phone network can do something similar by reporting how strong the signal is and what tower it's connected through. If it's in range of more than one tower, your position can be triangulated. If not, it just has to guess that you're within X feet/miles of a given tower.

My understanding of the iPad/iPhone is that they use a combination of GPS and cell towers. The cell towers give it a general position, which lets the GPS unit eliminate a lot of possibilities and narrow down your exact(ish) location more quickly.

So basically you can use any of the three (GPS, wifi, or cell) to find your location, but they vary in precision and reliability.

Thanks. Yes, that was my vague understanding, that GPS with wi-fi would get you close, but not precise. I can see that working for some apps, but wouldn't want to drive with directions that are sort of close. If that's the case, I'd rather read a map myself. I can do better than sort of close, lol.

By the way, so how does a GPS (the kind for your car) work?

[kjk]

Originally Posted by Maggie Leung

Thanks. Yes, that was my vague understanding, that GPS with wi-fi would get you close, but not precise. I can see that working for some apps, but wouldn't want to drive with directions that are sort of close. If that's the case, I'd rather read a map myself. I can do better than sort of close, lol.

Well, a lot of the dedicated car navigation systems run with just GPS, and they are pretty accurate!

[Maggie Leung]

Originally Posted by kjk

Well, a lot of the dedicated car navigation systems run with just GPS, and they are pretty accurate!

So when my car GPS is connecting to a satellite, what kinda communication is it using?