A system and a method for tracking users in a closed environment even in the case the available system for locating a user is an idle state is based on the use of a system which comprises a database for storing the location of the users measured at regular time interval within that closed environment. Such a system comprises further a processor for estimating the possible location of a registered user at any time according to the different stored measured location. Such estimation can be advantageously a statistical analysis corresponding to some daily geographical footprint of the registered user. The system comprises also a decision unit to provide the possible location of the registered user estimated for a specific time when required in the case the location measurement system is in an idle state. In that case, the estimated possible location can be forwarded to some PSAP.