Fireman emergency indoor positioning system

The invention discloses a fireman emergency indoor positioning system. The system is composed of an outdoor synchronization site, outdoor positioning sites and an indoor positioning terminal which is carried by a fireman. The synchronization site sends a range finding signal to each positioning site; the positioning sites modulate the range finding signals to a local carrier, generate carrier-suppressed double side band amplitude-modulated signals and radiate to the indoor positioning terminal; and the positioning terminal receives the composite signal, recognizes which positioning sites the signals respectively come from, calculates range finding signal phase difference of the positioning sites and calculates three-dimensional coordinates of the positioning terminal according to the hyperbolic positioning theory so as to realize real-time positioning and navigation of the fireman. The system has the following advantages: (1) the positioning sites and the positioning terminal don't need a synchronous circuit; (2) a low-frequency signal has a good wall-penetrating property; (3) the circuit is simple, positioning is easy to realize, and cost is low; (4) the positioning terminal has low power consumption and is small in size; and (5) infrastructure is not required, and the sites can be rapidly distributed and put into use.