Abstract: In AAL environments, a key issue is to know the location of a user in order to provide the required services quickly and efficiently. A good location system is the one that is able to locate an individual in the shortest time, with acceptable accuracy and spending the least resources as possible. In this context, it seems interesting to analyze in depth the existing location systems in order to optimize both their location procedures and the cost due to deployment. There are many ways to locate an individual indoors. This research is focused on Fingerprint based location procedure, making a comprehensive analysis of it, generating a broad and diverse set of assumptions and issues related to all the elements of the location process based on it. A tool called PosSimulator has been developed to help designers and AAL system evaluators choose the best deployment for a specific environment, taking into account the economic and installation cost and the position accuracy. PosSimulator has been designed regardless the technology used to acquire the information required to locate. It has been used in a test environment. There has been carried out an extensive battery of tests to extract answers or approaches to all the issues raised and research hypotheses, looking for clear trends in the accuracy of the location and observable connections among the various parameters in which the fingerprint based localization process is divided. For the test environment, it has been determined the best combination of all parameters.