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From: Woody on 27 May 2010 18:16 How does my new iPad (a 32GB wifi) know where it is? It isn't supposed to have a gps in it, even though it clearly has a compass. It doesn't have 3G, so it can't read 3G towers like the first iPhone did, so how does it know what road it is in, and where it is down the road? Or is it something simple such as it knows my home address. -- Woody www.alienrat.com
From: SteveH on 27 May 2010 18:28 Woody <usenet(a)alienrat.co.uk> wrote: > How does my new iPad (a 32GB wifi) know where it is? > > It isn't supposed to have a gps in it, even though it clearly has a > compass. > > It doesn't have 3G, so it can't read 3G towers like the first iPhone > did, so how does it know what road it is in, and where it is down the > road? > > Or is it something simple such as it knows my home address. It's some funkyness with the wifi signal, as I understand. -- SteveH
From: Woody on 27 May 2010 18:40 SteveH <italiancar(a)gmail.com> wrote: > Woody <usenet(a)alienrat.co.uk> wrote: > > > How does my new iPad (a 32GB wifi) know where it is? > > > > It isn't supposed to have a gps in it, even though it clearly has a > > compass. > > > > It doesn't have 3G, so it can't read 3G towers like the first iPhone > > did, so how does it know what road it is in, and where it is down the > > road? > > > > Or is it something simple such as it knows my home address. > > It's some funkyness with the wifi signal, as I understand. So it knows from my home wifi where it is? -- Woody www.alienrat.com
From: Rowland McDonnell on 27 May 2010 19:39 Woody <usenet(a)alienrat.co.uk> wrote: > SteveH <italiancar(a)gmail.com> wrote: [snip] > > It's some funkyness with the wifi signal, as I understand. > > So it knows from my home wifi where it is? Mine's off. Privacy requires this. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: David Empson on 27 May 2010 20:02
SteveH <italiancar(a)gmail.com> wrote: > Woody <usenet(a)alienrat.co.uk> wrote: > > > How does my new iPad (a 32GB wifi) know where it is? > > > > It isn't supposed to have a gps in it, even though it clearly has a > > compass. > > > > It doesn't have 3G, so it can't read 3G towers like the first iPhone > > did, so how does it know what road it is in, and where it is down the > > road? > > > > Or is it something simple such as it knows my home address. > > It's some funkyness with the wifi signal, as I understand. The key to understanding how it works is Skyhook Wireless. They have a massive database of WiFi base stations (identified by MAC address) and where they are physically located. If there are any WiFi networks in range of the iPad, the MAC address of those base stations are available to the iPad. (Even if the networks are secured; the SSID must be broadcast to make this easy.) If the iPad has an Internet connection (via WiFi), it can use the Skyhook Wireless service to look up the MAC addresses of all the visible base stations to see if any of them have been registered. If so, that gives it an approximate physical location, to within about 100 metres (assuming the coordinates of the base station are accurate). -- David Empson dempson(a)actrix.gen.nz |