Mayflower Communications Company, Inc.

Micrilor, Inc.

Massachusetts Institute of Technology

Corporation for National Research Initiatives

Other

Proxim Corporation

Sifos Technologies, Inc.

John H Cafarella

Jeffrey H Fischer

Triveni N Upadhyay

Huan-Wan Tseng

George Dimos

Jianhui Luo

Wallace E Vander Velde

Kendrick R Bennett

Robert E Kahn

Abraham Bers

Ernest R Stern

Richard C Williamson

Kjell Arne Ingebrigtsen

Peter G Johnson

Gowri Shankar Rajappan

Wallace Vander Velde

Ravi Sivasankaran

Stanley A Reible

A system and method for determining the roll rate and roll angle of a spinning platform by using the measured phase and/or amplitude differences between the GPS satellite signals received on two or more antennas. The measured signal differences and the navigation solution from a GPS receiver are processed in a roll filter to obtain the desired information. Data from non-GPS measurement sources is optionally provided to update the navigation solution. Although of wide applicability, the invention is uniquely suited to the measurement of roll rates and roll angles of fast spinning platforms with small baselines in the presence as well as in the absence of jamming, and where the antennas are separated from each other by distances that are a fraction of the GPS signal wavelength.

GPS-based roll rate and roll angle measurement in the absence of jamming

A system and method for determining the roll rate and roll angle of a spinning platform in a jamming environment, by suppressing the interference signals from the received GPS signals and using the measured phase and amplitude differences between the GPS satellite signals received on two or more antennas. The measured signal differences and the navigation solution from a GPS receiver are processed in a roll filter to obtain the desired information. Data from non-GPS measurement sources is optionally provided to update the navigation solution. Although of wide applicability, the invention is uniquely suited to the measurement of roll rates and roll angles of fast spinning platforms with small baselines in the presence of jamming, and where the antennas are separated from each other by distances that are a fraction of the GPS signal wavelength.

Antijam protected GPS-based measurement of roll rate and roll angle of spinning platforms

A system and method for determining the roll rate and roll angle of a spinning platform, using the measured phase differences between the GPS satellite signals received on two or more antennas. The measured phase differences and the navigation solution from a GPS receiver are processed in a Kalman filter to obtain the desired information. Data from non-GPS measurement sources is optionally provided to update the navigation solution. Although of wide applicability, the invention is uniquely suited to the measurement of roll rates and roll angles of fast spinning platforms with small baselines, in which the antennas are separated from each other by distances that are a fraction of the GPS signal wavelength.

GPS-based measurement of roll rate and roll angle of spinning platforms

An antijam filter and method for filtering interference signals from signals received from the desired user in spatially multiplexed wireless communication systems. The antijam filter estimates the interference from known and unknown sources, and uses that estimate to filter the interference from the received signals. The filtered desired user signals are rendered for further signal processing using existing methods. The antijam filter and method are modular, with applicability to a wide range of wireless communication systems employing multiple antennas at the receiver.

Antijam filter system and method for high fidelity high data rate wireless communication

An apparatus for measuring characteristics of a at least one Power Over Ethernet (PoE) Power Sourcing Equipment (PSE) device (also referred to as a PSE test blade) is presented. The apparatus includes a port controller and a current loading circuit in communication with the port controller. The apparatus further includes a resistance loading circuit in communication with the port controller, a capacitance loading circuit in communication with the port controller, and a load current and voltage measuring circuit in communication with the port controller. The apparatus further includes a first network providing the power signals to at least one of the current loading circuit, the resistance loading circuit, the capacitance loading circuit, and the load current and voltage measuring circuit. The port controller utilizes a set of test primitives which are accessed in real time via a user interface to execute test sequences for characterizing PSE devices.

Apparatus providing power-over-ethernet test instrument

Transceivers using direct conversion between baseband and RF have become popular for low-cost designs. Bandwidth-efficient modulations employ information on both phases of the carrier, and for high-order signaling alphabets, it becomes problematic to realize Direct-Conversion transceivers for which adequate gain balance between I and Q channels throughout the transmit and receive chains. For heterodyne transceivers I-Q balance is often less of an issue, by contrast, because most of the required gain operates at an Intermediate Frequency. In both cases, the trend toward lower supply voltages further exacerbates this problem because of the poorer control of analog parameters at low voltage. The present invention addresses this difficulty via a calibration method and system in which a calibration signal is generated in the transmit stage and injected into the receive stage so that any mismatches in gain can be observed and corrected.

Calibration of I-Q balance in transceivers

An apparatus and method for communicating data between at least two data devices, suitable for use as a wireless local-area network, that provides robust data communication via a radio communications channel corrupted by multipath interference, particularly at high data rates. A preferred embodiment of the invention represents data as a sequence of Walsh-function waveforms encoded by pseudo-noise direct-sequence spread-spectrum modulation. Walsh-function-encoding of the data provides a long symbol duration, thereby allowing the spread-spectrum modulation to provide processing gain sufficient to substantially overcome multipath interference, while providing a high data rate. In another preferred embodiment, Walsh-function modulation is supplemented with various forms of phase modulation, such as coherent PSK for bi-orthogonal signalling, and DPSK between orthogonal symbols for noncoherent bi-orthogonal signalling, thereby further increasing data rate without reducing processing gain. In another preferred embodiment, Walsh-function modulation is supplemented with spectral shaping to allow increased bandwidth occupancy, thereby further increasing the processing gain without sacrificing data rate.

High-data-rate wireless local-area network

An unconstrained pointing interface for natural human interaction with a display-based computer system includes a hand-manipulated pointer configured to permit it to be (1) aimed by line of sight to point at any arbitrary position within the user's field of view, including positions beyond the user's natural reach, and (2) swept along any arbitrary path and at any arbitrary speed within the user's natural capability. A detector detects emanations from at least some positions at which the pointer may be aimed; and circuitry identifies the locations of positions at which the user is aiming the pointer. The interface enables the user to point to a position within his field of view and beyond his reach, move his hand along any arbitrary path and at any arbitrary speed within the user's natural capability to point to another position, and so on, and to have the circuitry automatically identify the locations of the series of positions to which he has pointed.

Unconstrained pointing interface for natural human interaction with a display-based computer system

A data communications system for conveying a series of input data symbols includes a transmitter subsystem and a receiver subsystem. The transmitter subsystem generates a series of composite waveforms corresponding to a series of input data symbols by selecting from a set of mutually orthogonal component waveforms, then combines contemporaneous portions of at least two of the component waveforms so as to form a composite waveform which is unique to the data symbol. The transmit subsystem uses the composite waveform to modulate a carrier signal and transmits the carrier signal over a communications channel. The receiver subsystem receives the carrier signal and recovers the composite waveform from the carrier signal. The receiver subsystem identifies the data symbol by, at least in part, decompositioning the composite waveforms into their constituent component waveforms so as to identify which composite waveforms have been transmitted.

Wireless communications system for transmitting and receiving data with

An unconstrained pointing interface for natural human interaction with a display-based computer system includes a hand-manipulated pointer configured to permit it to be (1) aimed by line of sight to point at any arbitrary position within the user's field of view, including positions beyond the user's natural reach, and (2) swept along any arbitrary path and at any arbitrary speed within the user's natural capability, A detector detects emanations from at least some positions at which the pointer may be aimed; and circuitry identifies the locations of positions at which the user is aiming the pointer. The interface enables the user to point to a position within his field of view and beyond his reach, move his hand along any arbitrary path and at any arbitrary speed within the user's natural capability to point to another position, and so on, and to have the circuitry automatically identify the locations of the series of positions to which he has pointed.

Unconstrained pointing interface for natural human interaction with a

A hydroacoustic communication system employs spread spectrum to mitigate multipath interference caused by acoustic reflections off underwater surfaces and other large boundaries or acoustic discontinuities. The system is particularly beneficial for mitigating errors due to surface reflections, and for mitigating interference due to unwanted signals having a delay ranging from tens of microseconds to hundreds of milliseconds.

Hydroacoustic communications system robust to multipath

A surface acoustic wave device utilizing a piezoelectric substrate capable of propagating traveling acoustic waves along a surface thereof and a semiconductive substrate positioned adjacent such surface, the latter substrate having an array of diodes, preferably Schottky diodes, disposed in the surface thereof opposite the piezoelectric substrate to form an interaction region. Application of a signal uniformly over the interaction region will charge the diodes uniformly and a traveling acoustic wave will interact with the uniformly applied signal to alter the charging pattern of the array in accordance with the acoustic wave amplitude to produce a corresponding altered conductivity pattern in the semiconductor substrate representing the interaction of the uniformly applied signal and the traveling wave signal. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored altered conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface.

Surface acoustic wave devices for processing and storing signals

A continuously programmable matched filter device using a piezoelectric substrate capable of propagating acoustic wave signals on a selected surface thereof and a semiconductor substrate mounted adjacent and spaced from such surface. Means are provided for altering the conductivity pattern in the semiconductor substrate in accordance with the wave form of a reference wave signal so that a representation of the reference wave is effectively stored therein. Storage of the reference is achieved with electrostatic charge by supplying a plurality of electrons in the spatial region between the substrates or by manipulating the carriers in the semiconductor material into trapping states in order to produce such altered conductivity pattern. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored reference conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface.

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Swampscott, MA, United States of America

John H Cafarella