Detecting movement with an iphone

Can the iphone detect its movement in terms of distance?

Would one be able to use a built in function o开发者_JAVA百科n an iphone to determine the distance the phone has moved so that the speed of movement can be calculated?

Basically my question is

can an iphone detect its position and distance moved without using the gps?

thanks

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You probably could with some clever math. Basically, integrate over the accelerometer data.

For all the details, see http://www.freescale.com/files/sensors/doc/app_note/AN3397.pdf

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No, the only sensor that the device has that can calculate "distance" is via the Location API, which will make use of the GPS. Accelerometer and gyros (in iPhone 4) can give precise measurements of changes in orientation, but not distance travelled.

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Not easily, there are a couple of ways you can do this but they have severe limitations and you'll have to write all the code yourself.

One way is to use the accelerometer and try and calculate the distance from the forces on the phone, this is never going to be very reliable.

Another way is to use wifi, essentially looking at the signal strength to determine distance from the router (I think this is only possible using private APIs and requires several routers to be at all accurate). Or listen from a router to find out how far away the iPhone is.