Wherenet Corporation

Harris Corporation

University of Rochester

Zih Corporation

University of South Florida

Other

Honeywell International Inc.

Corning Incorporated

Duke University

Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

The Texas A&M University System

Zebra Technologies Corporation

University of Ottawa

Friedrich-alexander-universitaet Erlangen-nuernberg

Zebra Enterprise Solutions Corp.

Robert W Boyd

Donald K Belcher

Michael Andrew Wohl

David S Wisherd

Ronald J Hash

Zhimin Shi

Robert C Hildebrand

Daniel J Gauthier

Julian Bartow Willingham

Timothy C Harrington

Jerald W English

Thomas L Richardson

Darrick Hay

Yiyu Zhou

David J Stryker

David A Hosang

Ziyi Zhu

Nicholas Francis Borrelli

Daniel W Youngner

Paul A Tick

Lisa Lust

Marlan O Scully

Robert C Davis

Kenneth R MacDonald

Michael P O'Reilly

Guy M Pelchat

Santiago Romero

Laurie L Voci

Mark T Gruneisen

Alexey Belyanin

Mark D Skeldon

John E Sipe

Vitaly V Kocharovsky

Tom Richardson

William F Hartman

Paul Narum

Robert Jungquist

Carlos R Stroud

Samuel Lemieux

Mathieu Manceau

Gerd Leuchs

Stojan Radic

Maria V Chekhova

Clovis R Haden

G Alton Waschka

Mohammad Mirhosseini

Mehul Malik

John E Heebner

Svetlana G Lukishova

An example system for locating passive RFID tags includes a narrowband RFID reader configured to transmit a narrowband RF signal to energize a passive RFID tag, thereby causing the passive RFID tag to create a backscatter reflection target; a first wideband transceiver configured to transmit a wideband RF signal; a second wideband transceiver configured to: receive the wideband RF signal reflected from the backscatter reflection target; and record time-of-arrival data for the reflected wideband signal; and processing circuitry configured to determine a location measurement of the passive tag based on the time-of-arrival data.

Passive radio frequency identification ranging

An apparatus measures the transverse profile of vectorial optical field beams, including both the phase and the polarization spatial profile. The apparatus contains a polarization separation module, a weak perturbation module, and a detection module. Characterizing the transverse profile of vector fields provides an optical metrology tool for both fundamental studies of vectorial optical fields and a wide spectrum of applications, including microscopy, surveillance, imaging, communication, material processing, and laser trapping.

Measurement apparatus of wavefront and polarization profile of vectorial optical fields

A method and apparatus is provided for implementing a parametric down-conversion (PDC)-based calibration comprising calibrating a measuring instrument; disposing a pinhole at a position of a light-emitting sample for which the measuring instrument needs to be calibrated; irradiating a nonlinear crystal with a light source; setting the nonlinear crystal by ensuring a phase-matching wavelength of the nonlinear crystal is set at one boundary of a desired bandwidth; acquiring one or more PDC spectrums by the measuring instrument; obtaining peak values and their corresponding wavelengths from each acquired spectrum; and obtaining a response function based on the peak values and corresponding wavelengths.

Apparatus and method for calibrating measuring instruments

An example disclosed system for locating a signal source includes a receiver; and a plurality of node devices, wherein the receiver includes processing circuitry configured to perform operations including generating signal timing information including one or more pulses corresponding to a correlation with one or more frequencies based on each of a plurality of wireless signal streams, each of the wireless signal streams including a signal of interest; applying times and one or more determined gains for the signal of interest to permit estimate of a phase of the received signal; obtaining, from a memory device that stores the wireless signal streams, symbols of the signal of interest based on window periods associated with the pulses; formatting the symbols; and determining time-of-arrival information based on the formatted symbols.

Method, apparatus, and computer program product for processing received signals for locating

Systems, methods, apparatuses, and computer readable media are disclosed for providing timing-based distance measurement to a passive radio frequency identification ('RFID') tag using one or more wideband RF signals synchronized with the standard narrowband RF signal. In some embodiments, the narrowband RF signal activates a passive RFID tag creating a backscatter reflection target which returns a modulated narrowband signal and a wideband signal from the passive RFID tag. The one or more wideband receivers determine time-of-flight and/or time-of-arrival measurements for the returned wideband signal. A location measurement is then calculated for the passive RFID tag using the tag data, the known location of the wideband transceivers, and the time-of-flight/time-of-arrival data.

An example method includes identifying a link that is one of a plurality of links of a wireless locating system, the link being defined by at least a reference signal source, a first receiver unit, and a second receiver unit; determining a reliability metric for signal transmission via a link based on first link data, the link data describing first reference signal events for the link; and modifying the reliability metric based on second link data describing second reference signal events for the link, wherein modifying the reliability metric includes: determining whether the second link data is consistent with the first link data; adjusting the reliability metric using a first function when the second link data is consistent with the first link data; and adjusting the reliability metric using a second function different than the first function when the second link data is inconsistent with the second link data.

Method and apparatus for modeling time relationships between clocks

Systems and methods for determining signal source location in wireless local area networks are disclosed. An example method includes receiving, from a first signal reader, a first time-of-arrival measurement for a first radio frequency (RF) signal generated by a first wireless local area network (WLAN) signal source located at a first known location, the first time-of-arrival measurement being relative to a first clock of the first signal reader; receiving, from a second signal reader, a second time-of-arrival measurement for the RF signal, the second time-of-arrival measurement being relative to a second clock of the second signal reader, wherein the first clock is not synchronized with the second clock; defining a first time relationship between the first clock and a system time based on the first time-of-arrival measurement; and defining a second time relationship between the second clock and the system time based on the second time-of-arrival measurement.

System and method for determining signal source location in wireless local area network

A wavefront sensing technique using Polarization Rotation INTerferometry (PRINT) provides a self-referencing, high-resolution, direct measurement of the spatially dependent phase profile of a given optical beam. A self-referencing technique is used to create a reference beam in the orthogonal polarization and a polarization measurement to measure the spatial-dependent polarization parameters to directly determine the absolute phase profile of the beam under test. A high-resolution direct measurement of the spatially-resolved phase profile of one or more optical beams is realized.

Wavefront sensing apparatus, method and applications

Various methods for modeling timing relationships between clocks are provided. One example method includes identifying a link that is one of a plurality of links within a wireless locating system and receiving link data describing a reference signal event for the link. The example method may also include determining a reliability metric for the link based on the link data and comparing the reliability metric to a threshold reliability metric to determine whether the link is a reliable link. Further, the example method may include adding the link to a collection of reliable links for the wireless locating system, and generating a model describing a timing relationship between respective clocks of each of a plurality of receiver units in the wireless locating system based on link data for each of the reliable links. Related systems and apparatuses are also provided.

Method and apparatus for modeling timing relationships between clocks

Example embodiments are directed to various aspects of processing received signals for determining a location of a source of the signals. An example method may include generating signal timing information, and determining times for a plurality of window periods for the signal of interest based on the signal timing information. The example method may also include retrieving, from a memory device that stores the signal stream, symbols of the signal of interest based on the window periods, and formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest. Additional and alternative methods and apparatuses are also provided.

A system and method locates a wireless local area network (WLAN) signal source. A wireless LAN signal as an RF signal is propagated from a WLAN signal source at a fixed, known location to a plurality of receivers having unsynchronized clocks. The time-of-arrival is measured at each receiver and the timing relationship from the fixed, known location of the signal source is used to relate time-of-arrival measurements from a signal arriving from an unknown location.

According to the invention, a highly optically dispersive medium is one in which the absolute value of the group index of refraction of the medium is equal to or greater than four. An optical spectroscopic parameter detection and/or measurement apparatus may be in the form of an interferometer, a spectral interferometer, a spectrometer, a wavemeter, a tunable narrowband filter The embodied devices include a highly dispersive medium that appropriately can facilitate either a slow-light effect or a fast-light effect, which is disposed in a propagation path of an electro-magnetic (EM) input field and, a detector disposed in a manner to detect an output field resulting from the input filed interaction with the highly dispersive medium. Methods involve measuring a spectroscopic parameter using an optical spectroscopic parameter detection and/or measurement apparatus that incorporates a highly dispersive medium.

Apparatus and methods using highly optically dispersive media

A wireless local area network includes a plurality of access point stations that receive and transmit communications signals within the wireless local area network. A first set of access point stations are WiFi compliant and measure signal strength and determine the received signal strength indication (RSSI). A second set of access point stations are operable in accordance with the time of arrival (TOA) real time location standard (RTLS). A dual mode mobile station is operative for multimode communication with both the WiFi and RTLS compliant access point stations. A location processor is operatively connected with each of the access point stations and processes the RSSI and creates a RSSI locate map and processes communication signals from the second set of access point stations and determines which signals are first-to-arrive signals to locate the mobile station and update the RSSI locate map and locate any non-dual mode WiFi devices.

Location system for wireless local area network (WLAN) using RSSI and time difference of arrival (TDOA) processing

A method and system for detecting concealed weapons and explosives by imaging THz scenes using conventional optics and detectors is provided. Photon fields with two different wavelengths can be sent through a chopper and towards a wavelength-selective mirror. A light beam with a wavelength in the visible or IR range is sent toward a visible photon array detector. Similarly, light beams with wavelengths in the THz range can be sent towards a target, which are reflected and/or absorbed by objects in the target. The reflected or transmitted light continues on through an optional filter to remove background light, then into a non-imaging detector. The visible photon array detector can be coupled with the non-imaging detector, which will register an image of the scene that is illuminated by the THz photons.

Correlated ghost imager

Growing community of inventors

Rogersville, TN, United States of America

Robert W Boyd