Abstract: A device for activating a signal emitter for use in a firefighter locator system operates in conjunction with the firefighter's self-contained breathing apparatus (SCBA). The activation device includes a pressure sensor to monitor pressure on an air line that delivers air from the SCBA air tank to the SCBA air regulator. When the firefighter opens the SCBA air tank valve, pressure is sensed in the air line and the emitter is activated to transmit a signal. The signal is received by base stations that then use the signal to locate/track the signal emitter. Preferably, the activating system also includes a user operated reset button(s) and a shutoff circuit to allow the user to stop transmission of the signal by the signal emitter. The shutoff circuit is designed to stop transmission of the signal only after the air line has been depressurized and the reset button(s) is depressed.

Abstract: A wireless system and method for locating the position of a movable signal emitter located inside or adjacent to a structure includes establishing at least three base station sites at known locations around the structure. The signal emitter then transmits an omni-directional, low frequency, RF signal that is received at the base station sites. Phase information is measured at each base station site and communicated to a central processing site. At the central processing site, relative phase delays are used to geometrically calculate the position of the signal emitter.

Abstract: A system for tracking a moveable object such as a soldier in an urban environment includes a receiver that is positioned on the movable object and a plurality of signal transmitters. The transmitters are mutually dispersed at known locations within the urban environment and each transmitter is configured to generate a low frequency electromagnetic signal capable of penetrating into buildings in the urban environment. At the receiver, phase related information and the receiver location information are extracted from received signals and used to determine the location of the receiver. Phase related ambiguities can be eliminated by a processor to find the real receiver position using an algorithm such as the maximum likelihood method (MLM) algorithm. Once the real receiver position is calculated, it can be transmitted to a central location using a low probability of intercept (LPI) waveform to prevent hostile parties from intercepting the location of the soldier.

Abstract: A system for tracking a moveable object such as a soldier in an urban environment includes a receiver that is positioned on the movable object and a plurality of signal transmitters. The transmitters are mutually dispersed at known locations within the urban environment and each transmitter is configured to generate a low frequency electromagnetic signal capable of penetrating into buildings in the urban environment. At the receiver, phase related information and the receiver location information are extracted from received signals and used to determine the location of the receiver. Phase related ambiguities can be eliminated by a processor to find the real receiver position using an algorithm such as the maximum likelihood method (MLM) algorithm. Once the real receiver position is calculated, it can be transmitted to a central location using a low probability of intercept (LPI) waveform to prevent hostile parties from intercepting the location of the soldier.

Abstract: A device for activating a signal emitter for use in a firefighter locator system operates in conjunction with the firefighter's self-contained breathing apparatus (SCBA). The activation device includes a pressure sensor to monitor pressure on an air line that delivers air from the SCBA air tank to the SCBA air regulator. When the firefighter opens the SCBA air tank valve, pressure is sensed in the air line and the emitter is activated to transmit a signal. The signal is received by base stations that then use the signal to locate/track the signal emitter. Preferably, the activating system also includes a user operated reset button(s) and a shutoff circuit to allow the user to stop transmission of the signal by the signal emitter. The shutoff circuit is designed to stop transmission of the signal only after the air line has been depressurized and the reset button(s) is depressed.