Q-track Corporation

Eric Alexander Richards

Hans Gregory Schantz

Robert Edward DePierre

Alfred Hans Unden

Andrew Compston

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.

Method of near-field electromagnetic ranging and location

An inexpensive planar antenna fabricated as a plurality of parallel layers of multi turn spiral loops co-located with conductive material at the center of the loops, there being an exclusion zone free of conductive material between the innermost loop and the conductive material at the center. The conductive material may comprise circuit elements, for example batteries, amplifiers, antenna drivers or other functional elements as well as passive elements. In one embodiment, the loop traces may be staggered. In another embodiment, the loop traces are varied in width as a function of position within the loop cross section. In further embodiments, the planar form is integrated with additional orthogonal planar antennas substantially coplanar with the first planar antenna and having axes orthogonal to the first planar antenna and to one another. In further embodiments the exclusion zone is extended by design rules and confining routes in a circuit section. The antenna system may be configured as a three dimensional omnidirectional antenna and is well adapted for small form factor hand held and portable wireless applications.

Planar loop antenna system

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.

Growing community of inventors

Madison, AL, United States of America

Eric Alexander Richards