Abstract: A method of near-field electromagnetic ranging and location exploits the long-wavelength, near-field characteristics of low-frequency RF signals like those in the vicinity of the AM broadcast band. These signals are robust against scattering from small objects and only mildly perturbed by the urban landscape including building structures. They are thus amenable to an RF fingerprinting approach exploiting a coarse calibration to capture the behavior of the gradually varying signal characteristics. In embodiments, a method of near-field electromagnetic ranging and location may exploit transmit tags transmitting to an infrastructure of locator-receivers, or locator-receiver tags detecting signals from an infrastructure of fixed transmitter beacons. In still further embodiments, fixed transmitter beacons may be supplemented by uncooperative signals sources including signals-of-opportunity like AM broadcast band signals.

Abstract: The present application describes firefighter location and rescue equipment (FLARE) comprising: a plurality of tag transmitters, a first tag transmitter of said plurality of tag transmitters emitting a first signal, a plurality of locator-receivers receiving said first signal, each of said plurality of locator receivers determining a first set of signal characteristic data for said first signal, a computer compiling said first set of signal characteristic data in a reference database along with an associated path variable, a second tag transmitter of said plurality of tag transmitters emitting a second signal, a plurality of locator-receivers receiving said second signal, each of said plurality of locator receivers determining a second set of signal characteristic data for said second signal, said computer comparing said second set of signal characteristic data to the reference database, said computer displaying said comparison for evaluating the location of said second tag transmitter relative to a path take

Abstract: The present application describes firefighter location and rescue equipment (FLARE) comprising: a plurality of tag transmitters, a first tag transmitter of said plurality of tag transmitters emitting a first signal, a plurality of locator-receivers receiving said first signal, each of said plurality of locator receivers determining a first set of signal characteristic data for said first signal, a computer compiling said first set of signal characteristic data in a reference database along with an associated path variable, a second tag transmitter of said plurality of tag transmitters emitting a second signal, a plurality of locator-receivers receiving said second signal, each of said plurality of locator receivers determining a second set of signal characteristic data for said second signal, said computer comparing said second set of signal characteristic data to the reference database, said computer displaying said comparison for evaluating the location of said second tag transmitter relative to a path take

Abstract: A signal-of-opportunity location device (SOLD) that may be situated in a complex radio propagation environment with multiple RF signal obstructions receives RF signals from a distant transmitter. The RF signals from the distant transmitter interact with obstructions in the propagation environment local to the SOLD. The local obstructions perturb the RF signals causing the RF signals to exhibit near field behavior in the complex radio propagation environment. The SOLD receives the locally perturbed signals. The SOLD detects signal characteristics of RF signal components of the received signals and compares these signal characteristics with reference data in a reference data store to determine the current location of the SOLD.