Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A location system for tracking assets within a terminal includes a Differential Global Positioning System (DGPS) reference receiver within the terminal that receives GPS signals and generates DGPS correction data. In one aspect, a roving receiver unit is carried by an asset to be tracked within the terminal. It includes a GPS receiver that receives GPS signals and the DGPS correction data from the DGPS reference receiver. A tag transmitter transmits a wireless RF signal containing GPS location data based on received GPS signals and DGPS correction data. At least one access point is positioned within the terminal for receiving the wireless RF signal from the tag transmitter. A processor is operatively connected to the at least one access point for receiving GPS location data and determining a location of the asset to be tracked.

Abstract: 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.

Abstract: Embodiments of the invention pertain to the optical phenomena of ‘slow-light’ and ‘fast-light’, provided by a highly optically dispersive medium; that is, one in which the absolute value of the group index of refraction of the medium is equal to or greater than four. Apparatus embodiments of the invention are directed to an optical spectroscopic parameter detection and/or measurement apparatus. In various non-limiting aspects, the apparatus may be in the form of an interferometer, a spectral interferometer, a spectrometer, a wavemeter, a tunable narrowband filter, and other such devices. Various non-limiting, exemplary apparatus may include a two-beam interferometer, a multiple-beam interferometer, a grating-based interferometer/spectrometer, a Fourier-Transform interferometer, and others.

Abstract: A location system for tracking assets within a terminal includes a Differential Global Positioning System (DGPS) reference receiver within the terminal that receives GPS signals and generates DGPS correction data. In one aspect, a roving receiver unit is carried by an asset to be tracked within the terminal. It includes a GPS receiver that receives GPS signals and the DGPS correction data from the DGPS reference receiver. A tag transmitter transmits a wireless RF signal containing GPS location data based on received GPS signals and DGPS correction data. At least one access point is positioned within the terminal for receiving the wireless RF signal from the tag transmitter. A processor is operatively connected to the at least one access point for receiving GPS location data and determining a location of the asset to be tracked.

Abstract: 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.

Abstract: An efficient technique for producing deterministically polarized single photons uses liquid-crystal hosts of either monomeric or oligomeric/polymeric form to preferentially align the single emitters for maximum excitation efficiency. Deterministic molecular alignment also provides deterministically polarized output photons; using planar-aligned cholesteric liquid crystal hosts as 1-D photonic-band-gap microcavities tunable to the emitter fluorescence band to increase source efficiency, using liquid crystal technology to prevent emitter bleaching. Emitters comprise soluble dyes, inorganic nanocrystals or trivalent rare-earth chelates.

Abstract: 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.

Abstract: Systems and method for manipulating optical pulses to implement an optical switch and for pulse shaping (e.g., pulse compression and/or compression) are disclosed. In one embodiment, the system comprises an optical switch apparatus that includes a plurality of resonators optically coupled to a waveguide, two output waveguides, an input light source, a control light source. The system selects some of the input signals emitted from the input light course using control signals emitted from the control light source to route to one of the output waveguides. In another embodiment, the system includes a waveguide optically coupled to a plurality of resonators, input light source, optional resonator modules that can change the refractive index of the resonators, and an optional amplifier. This system can change the shape of the pulses by changing a number of parameters, such as the incoming pulse amplitude and/or the refractive index of the resonators.

Abstract: A system for locating an object within a monitored environment includes receivers arranged in loosely coupled networks. A tag transmitter acts as a network node and bridge between the loosely coupled networks. A processor is operative with each receiver within each network for defining a clock timing for each network, a system time for all networks, and tracking its relationship to the clock timing for each network for time synchronizing all receivers. The processor is also operative for conducting differentiation of time of arrival signals received from a tag transmitter to locate an object associated with the tag transmitter.

Abstract: A location system includes a plurality of signal readers for receiving signals from a wireless transmitter to be located. The signals include a wideband, spread spectrum signal and a timing marker appended a predetermined time in front of the wideband, spread spectrum signal for indicating the presence of the wideband, spread spectrum signal. A location processor is operatively coupled to the signal readers for detecting the timing markers of signals and responsive to a detection of a timing marker, correlating a signal as a first-to-arrive signal and conducting differentiation of first-to-arrive signals to locate a wireless transmitter.

Abstract: A system for locating an object within a monitored environment includes a tag transmitter that transmits an RF signal to receivers having unsynchronized clocks. A processor is operative with each receiver and determines clock timing relationships for the clocks based on one of at least propagation or processing delays in the receivers to synchronize receiver performance.

Abstract: A system of the present invention is operative for locating a wireless mobile device in communication with a wireless local area network (WLAN) that includes a plurality of cells defining a wireless local area network each having an access point base station. The access point base stations communicate with wireless mobile devices using wireless communication signals as typically spread spectrum communication signals. A processor is operatively connected to each of the access point base stations and operative to process communication signals transmitted from a mobile device and determine which signals are first-to-arrive signals based on a common timing signal and conduct differentiation of the first-to-arrive signals to locate the mobile device.

Abstract: A wireless local area network and location system for locating objects within a monitored environment are disclosed. A plurality of access point stations receive and transmit communication signals within a wireless local area network. A processor is operatively connected to each of the access point stations and operative for processing communication signals received from the mobile station and, in one embodiment, determining which communication signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a mobile station. Delayed versions of at least one interference signal are weighted and the amplitude and phase controlled with weighted functions W1, W2 . . . Wn. The resultant weighted replicas are summed to determine an approximation of disbursed interference for cancelling interference. The location system can include a tag transmitter and spaced monitoring receivers and processor.

Abstract: A document verification scheme embeds in or deposits on a substrate/document a random distribution of dielectric particles that effectively create a unique electronically detectable signature. The dielectric constant of the particles is sufficiently larger than that of the substrate/document, so as to exhibit molecular level electric dipole moments, which cause a detectable modification of an external electric field passing through the substrate. Electronic signature verification is effected by comparing the digitized output of an electric field modification sensor with a digital code that has been stored previously in the data base. As long as the substrate containing the dielectric particle signature has not been altered, its randomly distributed capacitance characteristic will remain unchanged, and the two digital signatures seen by the comparator will effectively match one another, verifying authentication of the substrate.

Abstract: In order to geolocate a wireless communication device (cellular phone) initiating a 911 call, a base station transceiver transmits a supervisory audio tone (SAT), which is automatically looped back by the calling cellular phone. Returned SAT signals are correlated with those transmitted to determine the range of the cellular phone. In addition, incoming signals from the cellular phone, such as the returned SAT signals, are received by a phased array antenna and subjected to angle of arrival processing to determine the direction of the cellular phone relative to the base station. Given this angle of arrival and range information the cellular phone is geolocated.

Abstract: According to one embodiment, detecting radiation includes receiving a first laser drive field at a cell comprising a medium having a number of states. The first laser drive field has a frequency approximately equivalent to a transition frequency between a first state and a second state. A second laser drive field having a frequency approximately equivalent to a transition frequency between the first state and a third state, and an infrared field having a frequency approximately equivalent to a transition frequency between the third state and a fourth state are received. The medium has a transition between the second state and the third state substantially forbidden to support optimal coherence on the transition between the second state and the third state. The infrared field is upconverted to generate a detectable field having a frequency approximately equivalent to a transition frequency between the second state and the fourth state.