Measuring short distances

Question

What's the best way to wirelessly measure the distance between two objects (computer, smartphones or a specialised device) that are a few meters apart down to a ~10cm accuracy? Is this possible by piggybegging on WLan, bluetooth or GPS?

Answer 1

Ekahau specialise on doing this kind of thing with WiFi. You're better off using light to get precision measuring as RF (Radio Frequencies) can be distorted by the environment. There are numerous patents in this area for many of the 'good' solutions.

Answer 2

GPS won't give you 10cm accuracy. You might get something like on the order of metres.

It sounds like Bluetooth can be used for indoor localization, but I am not sure as to the availability of API's and the like to make the job easier.