Bluetooth Tracking

In an earlier post I mentioned that mine and Jon's project will be using Bluetooth so decided I would look into things that are possible with using bluetooth. One option is Bluetooth tracking.
Locating several Bluetooth signals is easy with a typical mobile phone because you can just turn your phone on and it will pick up a Bluetooth signals from phones within a certain radius. But it is this radius which limits this because to track a certain device we would have to follow the person whose signal it is and that would look very odd indeed! So we would have to use something with a far bigger radius if we were to achieve a better result.
Of course we are not looking to track someone wherever they go we simply want to monitor a small area of Stonehouse, most likely to be a street. We would then be able to tell what direction people are walking down the street because we could tell how far away the signal is getting and whether it is getting closer to our tracking device or further away.