Location is an important topic on Ambient Intelligence. Different techniques are used, alone or together, to determine the
position of people and objects. One aspect of this problem concerns to indoor location. Various authors propose the analysis
of Radio Frequency (RF) signatures as a solution for this challenge. An approach for indoor location is the use of RF signals
acquired from a Global System for Mobile Communications (GSM) by Mobile Units(MU).
In this paper we make a study based on around 485.000 signatures gathered from four buildings. We present our conclusions
on the suitability and limitations of this approach for indoor location.