Localize a miniature FM transmitter from a mobile

[xflamant]

Hello,

I am an engineer in web application development and I am newbie in electronics and mobile programmation and I would like to develop an application on mobile that can localize (display the length between my mobile and the transmitter) a miniature FM transmitter.

First of all I would like to know if it is possible to develop such an application.

I inquired on internet that there exist FM transmitters that emits on frequencies from 300Mhz to 900 Mhz. Does all mobile can detect these plage of frequencies ? Then to recognize The signal comming from the transmitter, do I need to send special information from my transmitter. And does the mobile has to convert the received signal to decode the former information comming from the transmitter. I understood that we have to use a FM tuner to decode radio signal and that mobiles haven't such tuner. So is there another mean to receive, detect the right signal (with information as a code) ?

Thanks in advance for your answers

[RayHaddad]

So many things to consider.

Starting out, if you are going to use your own transmitter, all you need to get your distance only as the ability to read power. Since you know your own transmitter's signal strength, the power will diminish by a known amount based on the distance. Easy.

If you are going to be measuring the distance to an unknown transmitter, then you need two points at a minimum to range the distance based on geometry rather than power. With the power embedded in a typical phone, you don't need much separation between measurements. A few yards will do for a transmitter less than a few thousand yards away.

I'll leave you with these hints but you will have to develop your own means. Good luck.