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522 results about "Decorrelation" patented technology

Decorrelation is a general term for any process that is used to reduce autocorrelation within a signal, or cross-correlation within a set of signals, while preserving other aspects of the signal. A frequently used method of decorrelation is the use of a matched linear filter to reduce the autocorrelation of a signal as far as possible. Since the minimum possible autocorrelation for a given signal energy is achieved by equalising the power spectrum of the signal to be similar to that of a white noise signal, this is often referred to as signal whitening.

Reduction of echo decorrelation facilitating motion estimation

Methods systems and computer readable media are provided for extracting information pertaining to at least one moving target. A set of signal data are inputted to a principal components processor, wherein the set of signal data comprise signal data corresponding to at least one waveform acquired from the at least one moving target. A complex representation of the set of signal data is formed and, using a principal components processor, at least one complex principal component of the complex representation is calculated. At least one of the calculated complex principal components is automatically selected and each of the at least one automatically selected complex principal component is applied to extract information about the at least one moving target. Methods systems and computer readable media are provided extracting information pertaining to at least one moving target. A set of signal data comprising signal data corresponding to at least one waveform acquired from the at least one moving target are inputted to a principal components processor. A complex representation of the set of signal data is formed, and at least one complex principal component of the complex representation is calculated. An estimated value of a physical characteristic of the at least one moving, target is then calculated, using a phase of at least one of the at least one complex principal components.
Owner:UNIV OF VIRGINIA ALUMNI PATENTS FOUND

Method and system for on-line blind source separation

A method and apparatus is disclosed for performing blind source separation using convolutive signal decorrelation. For a first embodiment, the method accumulates a length of input signal (mixed signal) that includes a plurality of independent signals from independent signal sources. The invention then divides the length of input signal into a plurality of T-length periods (windows) and performs a discrete Fourier transform (DFT) on the, signal within each T-length period. Thereafter, estimated cross-correlation values are computed using a plurality of the averaged DFT values. A total number of K cross-correlation values are computed, where each of the K values is averaged over N of the T-length periods. Using the cross-correlation values, a gradient descent process computes the coefficients of a finite impulse response (FIR) filter that will effectively separate the source signals within the input signal. A second embodiment of the invention is directed to on-line processing of the input signal—i.e., processing the signal as soon as it arrives with no storage of the signal data. In particular, an on-line gradient algorithm is provided for application to non-stationary signals and having an adaptive step size in the frequency domain based on second derivatives of the cost function. The on-line separation methodology of this embodiment is characterized as multiple adaptive decorrelation.
Owner:GOOGLE LLC

CE-OFDM (Constant Envelope Orthogonal Frequency-Division Multiplexing) based radar communication integration system

The invention belongs to the field of radar technologies, and relates to a CE-OFDM (Constant Envelope Orthogonal Frequency-Division Multiplexing) based radar communication integration system. The invention is a CE-OFDM based super-resolution radar communication integration scheme which is provided on the basis of a traditional OFDM radar communication integration scheme, compensated through communication information, and capable of improving the effective data transmission rate and solving a problem that the PAPR of OFDM signals is too high. A transmitting terminal firstly turns data to be transmitted into CE-OFDM symbol frames through QAM (Quadrature Amplitude Modulation), IFFT (Inverse Fast Fourier Transform) and phase modulation, and a single pulse in a pulse repetition period is replaced by using a CE-OFDM symbol, so that the data transmission rate is improved, and the problem that the PAPR of transmitted signals is too high is solved. At a receiving terminal, received waveform pulses are demodulated, an inverse process of the transmitting process of the CE-OFDM system is carried out on the signals, and data can be demodulated; and the transmitting waveform is known, pulse compression processing is carried out on received echo waves, and super-resolution estimation for the distance and the speed of a target can be accomplished through decorrelation processing and an MUSIC algorithm after information compensation.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Rolling bearing fault on-line detection and state assessment method

A rolling bearing fault on-line detection and state assessment method is disclosed. The method comprises the following steps: twelve dimensional dimensionless parameters are extracted; the twelve dimensional dimensionless parameters comprise six dimensional time domain statistical parameters, three dimensional frequency domain statistical parameters and three dimensional dimensionless parameters in a small wave envelope spectrum; standardized reconstruction characteristic vectors can be obtained; whether a rolling bearing malfunctions is determined, and a state of the rolling bearing is assessed. Via the rolling bearing fault on-line detection and state assessment method, the twelve dimensional dimensionless parameters which can be used for effectively representing the state of the rolling bearing can be automatically extracted, the twelve dimensional dimensionless parameters are subjected to decorrelation and standardization operation, standardized reconstruction characteristic vectors that are distributed to form a hypersphere with an original point being a sphere center, and fault detection and state assessment of the rolling bearing can be realized via 2-norms of the standardized reconstruction characteristic vectors; difficult problems of long on line training time, low efficiency, and hard-to-obtain fault samples and the like of a rolling bearing state assessing model can be solved.
Owner:CHINA AERO POLYTECH ESTAB

Method for monitoring and resolving three-dimensional ground surface deformation of industrial and mining area by means of multi-source SAR image

ActiveCN106526590AComprehensive real space-time characteristicsComprehensive and realistic access to spatio-temporal propertiesRadio wave reradiation/reflectionGeomorphologyRadar
The invention discloses a method for monitoring and resolving three-dimensional ground surface deformation of an industrial and mining area by means of a multi-source SAR image. The method is based on SAR image data of different rails before and after deformation. Deformation information in different radar satellite visual line directions are obtained through combining D-InSAR technology and Offset-tracking technology. Deformation information in different radar satellite azimuth directions is acquired through combining MAI technology and Offset-tracking technology. Based on this fact, different deformation information monitoring precisions in the viewing line direction and the azimuth direction are considered. Weights are determined in a Helmert variance component estimation manner. A three-dimensional land surface deformation conversion model is established and resolved, thereby obtaining a three-dimensional deformation field of the industrial and mining area. The method can settle a problem of easy restriction by factors such as decorrelation and small monitorable deformation gradient. Furthermore, the true ground surface deformation condition is more comprehensively monitored through the multi-source SAR image.
Owner:SHANDONG UNIV OF SCI & TECH

Broadband signal arriving direction estimation method based on iteration spectral reconfiguration

InactiveCN103091661AOvercoming the defect of requiring angle pre-estimationOvercoming the defect of angle pre-estimationRadio wave direction/deviation determination systemsFourier transform on finite groupsCovariance matrix
The invention discloses a broadband signal arriving direction estimation method based on iteration spectral reconfiguration. The realizing process comprises the steps of transforming array antenna receiving data into a frequency domain through windowing Fourier transform, conducting multi-sub-band frequency domain segmentation to the data in the frequency domain, initializing each covariance matrix of each sub-band, obtaining an initialized power matrix of a frequency point according to a covariance matrix of one frequency point in the sub-bands, updating the covariance matrix of a signal at the position of the frequency point according to the initialized power matrix, obtaining corresponding optimum weight of a search angle space by the adoption of the least-squares method, updating the power of each corresponding angle according to the optimum weight on each search angle to obtain the initialized power matrix of a next frequency point and conducting iteration process, and estimating the signal arriving direction through a power spectral peak of the search angle space. The broadband signal arriving direction estimation method based on the iteration spectral reconfiguration can estimate the signal arriving direction of an incidence signal source under the conditions of weak signals and short data, is high in precision, and has the advantage of decorrelation.
Owner:XIAN UNIV OF SCI & TECH

Method and system for on-line blind source separation

A method and apparatus is disclosed for performing blind source separation using convolutive signal decorrelation. For a first embodiment, the method accumulates a length of input signal (mixed signal) that comprises a plurality of independent signals from independent signal sources. The invention then divides the length of input signal into a plurality of T-length periods (windows) and performs a discrete Fourier transform (DFT) on the signal within each T-length period. Thereafter, estimated cross-correlation values are computed using a plurality of the averaged DFT values. A total number of K cross-correlation values are computed, where each of the K values is averaged over N of the T-length periods. Using the cross-correlation values, a gradient descent process computes the coefficients of a FIR filter that will effectively separate the source signals within the input signal. A second embodiment of the invention is directed to on-line processing of the input signal—i.e., processing the signal as soon as it arrives with no storage of the signal data. In particular, an on-line gradient algorithm is provided for application to non-stationary signals and having an adaptive step size in the frequency domain based on second derivatives of the cost function. The on-line separation methodology of this embodiment is characterized as multiple adaptive decorrelation.
Owner:GOOGLE LLC
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