System and method to locate a person in a multi-level building, including: a portable transmitter coupled to the person, the portable transmitter configured to transmit a signal comprising an identification code; a plurality of receivers located in a multi-level building to receive the signal, substantially each receiver producing a received signal, wherein at least a first receiver is located on a first level and at least a second receiver is located on a second level, wherein the second level is different than the first level; a signal strength estimator coupled to at least one receiver, the signal strength estimator configured to produce a signal strength estimation of the received signal received by the at least one receiver; and a processor configured to receive the signal strength estimations, and from the signal strength estimations calculate a level of the multi-level building on which the person is located.