Handset-Based Positioning System for Injured Fireman Rescue in Wildfire Fighting

Injured fireman rescue is an emergent task in firefighting, where a rapid localization plays a significant role. For an indoor fire inside a building, a distributed system, i.e., a sensor network, can be preset surrounding the building for indoor positioning. However, for an accidental wildfire, it is intuitively impossible to preset this kind of on-site positioning system since the scene of this accident is unknown in advance and it is expandable. In this paper, a handset-based positioning system using mobile base stations (MBSs) is presented for injured fireman rescue in wildfire fighting and is compared with the network-based positioning system. This system is built on the scene right after the accident occurs and moves according to fire spreading. An orthogonal frequency-division multiplexing signal is selected as the probing signal for this application, because it has a much greater nonambiguity ranging distance than pulse-based ultrawideband signal, outperforms pseudorandom noise signal, and is robust against multipath. A multiple-access scheme is proposed for all MBS simultaneous transmissions without interference. Furthermore, a novel signal acquisition and tracking algorithm is proposed using phase correlation to further overcome the multipath effect. In addition, the 3-D localization and performance are discussed. Simulation results demonstrate our proposed system and algorithms.