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342 results about "Galerkin least squares" patented technology

Sensor-fault diagnosing method based on online prediction of least-squares support-vector machine

The invention discloses a sensor-fault diagnosing method based on the online prediction of a least-squares support-vector machine. In the method, a least-squares support-vector machine online-predicting model is established, and then the measured data of a sensor is acquired on line and used as an input sample of the least-squares support-vector machine online-predicting model to realize that the output value of the sensor at the next moment is predicted in real time as the predicting model is trained on line. Whether sensor faults occur or not is detected by comparing residual errors generated by the predicting value and the actual output value of the sensor. When the faults occur, the unary linear regression for a residual-error sequence is carried out by a least-squares method to realize the identification of the deviation and drift faults of the sensor, and furthermore, measures can be more effectively taken to carry out real-time compensation for the output of the sensor. Through the sensor-fault diagnosing method, the online fault diagnosis of the sensor can be rapidly and accurately realized, and the sensor-fault diagnosing method is particularly applicable to diagnosing the deviation faults and the drift faults of the sensor.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Road conditions video camera marking method under traffic monitoring surroundings

InactiveCN101118648AImprove robustnessMeet the requirements of high-precision camera calibrationTelevision system detailsImage analysisMonitoring systemModel parameters
A road condition video camera demarcating method under the traffic monitoring condition includes the following demarcating steps: (1) visual model describing and relevant coordinate system creating: according to the requirement of the monitoring system performance, a classical Tsai transmission projection model is used for reference, and according to the feature of the road condition imaging, a new visual model is presented after conducting corresponding amendment on the classical Tsai transmission projection model, and three kinds of coordinates are established. (2) demarcating the main point of a video camera and the extension factor: the image monitoring light stream is used as the demarcating basic element; by the extension movement of the video camera, a reference frame forecast image and the difference value of the light stream field in a real time frame sampling image are used as the restriction, a constraint equation is established by adopting the least square method, the main point coordinate of the video camera and the actual magnification coefficient of the video camera can be distinguished by the powell direction family method. (3) Demarcated object selecting and parameter linearity evaluating. (4) Accuracy making on the internal and external parameters of the video camera: according to all the angle points of the monitored image and the corresponding world coordinate point, the Levenberg-Marguardt optimization algorithm is adopted to make accuracy on the video camera model parameter, and then the video camera demarcating is finished.
Owner:NANJING UNIV

Round array phase interferometer two-dimensional (2D) direction-finding method based on virtual base line

The invention belongs to the technical field of communication radar, in particular relates to a broadband phase interferometer two-dimensional (2D) direction-finding method in radio monitoring. The invention provides a least square phase interferometer 2D direction-finding method based on a virtual base line defuzzification. The method comprises the following steps: firstly performing the virtualbase line conversion on a phase difference vector that is really measured on a short base line and has phase ambiguity once or several times so as to obtain a non-ambiguity virtual phase difference vector corresponding to the short base line; then orderly performing the defuzzification on the virtual phase difference vector, an adjacent base line phase difference vector and the longest base line phase difference vector, which all have ambiguity, according to the virtual phase difference vector, and finally estimating an incident direction by using the least square method according to the non-ambiguity longest base line difference vector. The defuzzification based on the virtual base line conversion provided by the invention can be used for obtaining a high-accuracy and non-ambiguity 2D direction-finding result in existence of angle-measuring ambiguity, and is an efficient 2D angle-measuring algorithm.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

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 for detecting synchronous vibration parameters of high-speed rotary blade under constant speed

ActiveCN101629846AEasy to measureMeet the needs of real-time online monitoringVibration measurement in solidsResonant frequencyDouble ValueMultiple sensor
The invention relates to a method for detecting vibration of a blade of a rotary machine, in particular to a method for detecting synchronous vibration parameters of a high-speed rotary blade under a constant speed. In order to eliminate limitation of taking uniform variable speed running as a precondition and meet the demand of real-time online monitoring, the invention adopts the technical scheme that based on a bladetip timing vibration detection principle, the synchronous vibration displacement yi of a certain blade, detected by a bladetip timing sensor, is indicated as following: yi=Asin(Nealphai+Phi0)+C(i=0,1,2...). A frequency doubling traversal range containing actual synchronous vibration frequency doubling Ne of the blade is selected, and then an actual installing included angle alphai of the bladetip timing sensor and the selected frequency doubling Nej are substituted into the formula so as to work out the vibration displacement of different frequency doubling corresponding to a multiple-sensor theory measured by a least square method; the square and the radix of an error between the calculated vibration displacement and the vibration displacement of actual measurement are worked out, and the frequency doubling of the minimum value of the square and the radix of the error is taken as the frequency doubling value of the actual vibration of the blade in a frequency doubling traversal process. The invention is mainly applied to the method for detecting the vibration of the blade of the rotary machine.
Owner:ZHEJIANG ZHONGXIN POWER MEASUREMENT & CONTROL TECH

Seismic wave full waveform inversion method based on least square gradient update speed model

ActiveCN105005076AImprove update gradient accuracyQuick updateSeismic signal processingWave fieldFull waveform
The present invention relates to a seismic wave full waveform inversion method based on a least square gradient update speed model, comprising the following steps: 1) obtaining a sound wave equation of a seismic wave field in time domain; 2) constructing an initial speed model, setting a speed model update iteration number N and an allowed minimum error value epsilon; 3) constructing observation wave field data and calculating a wave field error vector of the wave field data; 4) constructing an object function; 5) calculating the object function to obtain a standard equation of seismic wave full waveform inversion; 6) introducing a speed model update gradient direction g<k> and an update amount step length alpha; 7) solving the speed model update gradient direction g<k> by using a least square method; 8) performing interpolation calculation for the update amount step length alpha; and 9) updating the speed model, wherein m<k>=m<k-1>+alpha*g<k>; when |alpha*g<k>| < epsilon or the update number of the speed model reaches the speed model update iteration number N, ending the update of the speed model; otherwise, entering into the step 3). The seismic wave full waveform inversion method of the present invention can quickly achieve update of the speed model, and can be widely applied in seismic wave full waveform inversion.
Owner:CHINA NAT OFFSHORE OIL CORP +1

Dynamically rotary modulated north-seeking method for gyroscope

The invention belongs to the field of an inert measuring technique or geophysical experiment and instrument, in particular to a dynamically rotary modulated north-seeking method for a gyroscope. The dynamically rotary modulated north-seeking method for the gyroscope provided by the invention aims to realize fast and precise north-seeking measurement under the condition that a carrier has a large attitude angle without leveling or knowing the latitude of a measuring point, so that the speed of geodesic operation is improved. A rotary table which rotates uniformly at an angular speed Omega is used. The rotary table is provided with the gyroscope and two accelerometers. The method comprises the steps of: first, solving an angle of pitch and a roll angle by the two accelerometers; then, solving the geographic latitude L and a course angle by the gyroscope; and after calculating an initial value, improving the precision by using a real time recursive least square method. The dynamically rotary modulated north-seeking method for the gyroscope provided by the invention has the advantages that fast and precise north-seeking measurement can be realized under the condition without leveling or knowing the latitude of the measuring point, so that the speed of geodesic operation is improved.
Owner:西安测绘研究所

Time frequency domain time varying structure modal parameter identification method based on time varying common demominator model

The invention relates to a time frequency domain time varying structure modal parameter identification method based on a time varying common demominator model and belongs to the technical field of structural dynamics. Firstly, structural dynamics response signals measured and obtained by aircraft or spacecraft structures with the time varying characteristics under the work situations are analyzed in a time frequency mode to obtain a time relative power spectral function of non-parametric evaluation corresponding to time varying structures. Then, the time varying common demominator model is used as a parametric model of the time varying structural dynamics to evaluate to-be-evaluated parameters of the time varying common demominator model through a least squares methods of the time domain. Finally, the evaluated to-be-evaluated parameters of the time varying common demominator model is utilized to calculate the model frequency and the model damping ratio corresponding to the time varying common demominator model. The time frequency domain time varying structure modal parameter identification method based on the time varying common demominator model is suitable for model parameters recognition of time varying structure in the field of aircraft and spacecraft engineering application and has the advantages of being simple and convenient to use. Furthermore, users are low in participation degree.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

RBF neural network modeling method based on feature clustering

The invention relates to an RBF neural network modeling method based on feature clustering, which belongs to the field of automatic control, information technology and advanced manufacture. The invention particularly relates to an RBF neural network modeling method based on feature extraction function clustering, which can solve the modeling problem that data can be scattered. The method is characterized by comprising the following steps: defining a feature extraction function based on existing mechanism knowledge, determining an RBF network center in a clustering algorithm based on the feature extraction function, and determining a weight value from the hidden layer to the output layer of the RBF network in a least square method. The invention also provides a clustering algorithm based on the feature extraction function, which is not used for directly clustering data, but is used for clustering data with scattering features through introduction of the feature extraction function based on the mechanism knowledge. The obtained clustering center is used as the RBF network center, and the weight value from the hidden layer to the output layer of the RBF network can be obtained with a linear interpolation method. The invention can effectively solve the modeling problem that the data has scattering features, and can achieve high modeling accuracy.
Owner:TSINGHUA UNIV

Mutual coupling condition-oriented bistatic MIMO (multiple-input multiple-output) radar angle estimation method

The present invention discloses a mutual coupling condition-oriented bistatic MIMO (multiple-input multiple-output) radar angle estimation method. According to the method, radar data which have been subjected to matched filtering are expressed as a third-order tensor model by means of the multi-dimensional structure of array signals; since a uniform linear array mutual coupling matrix has a strip-shaped Toeplitz feature, the common scale conversion feature of a part of an array element directional matrix is utilized to eliminate the influence of mutual coupling; on the basis of a forward-backward smoothing technique and a unitary transformation technique, the augmented output trilinear model of decoupling-post data is constructed; and joint DOD (direction-of-departure) and DOA (direction-of-arrival) estimation is related with the trilinear model; and a target DOD and DOA are estimated through the least squares method. Compared with a traditional algorithm, the bistatic MIMO (multiple-input multiple-output) radar angle estimation method under the mutual coupling condition can effectively deal with situations where mutual coupling exists between a transmitting array and a receiving array, can automatically match the estimated DOD and DOA, and can reduce computational complexity by using a feature that trilinear decomposition only involves real number operation.
Owner:YANGTZE UNIVERSITY

Method for realizing sparse signal recovery on CPU (Central Processing Unit) based on OMP (Orthogonal Matching Pursuit) algorithm

The invention discloses a method for realizing sparse signal recovery on a CPU (Central Processing Unit) based on an OMP (Orthogonal Matching Pursuit) algorithm. The method comprises the following steps of: generating an observation matrix on the CPU, and selecting a column with the greatest relevancy to the residual in the observation matrix to complement a basis matrix, wherein the residual is the difference between the observations generated by an actual observation signal and an estimation signal, and the basis matrix is a matrix formed by nonzero element index values in corresponding column vectors in the observation matrix; by use of a method of least squares, estimating the nonzero elements of an original signal on the basis matrix of the kth step; continuing to select the column with the greatest relevancy to the residual in the observation matrix on the CPU to complement the basis matrix, when the variance between the real observation and the estimation observation is lower than a specified threshold, ending the iterative operation. The method provided by the invention has the following advantages: in parallel realization of the OMP algorithm by the CPU, the advantages of low computational complexity and high convergence rate of the OMP algorithm are combined, and simultaneously, the characteristic of remarkable acceleration performance of the CPU algorithm to the vector computation is fully used, and the running speed of the sparse recovery algorithm is improved effectively.
Owner:TSINGHUA UNIV

Method for positioning dual-system combined satellite navigation receiver

The invention discloses a method for positioning a dual-system combined satellite navigation receiver, which comprises the following steps of: firstly, acquiring positions of satellites and the pseudo-range observed quantity; secondly, according to different conditions for observing the satellites, adopting different steps to finish the positioning of the receiver so as to acquire the position of the receiver; and finally, outputting positioning results The method has two solutions according to the number of visible satellites: firstly, under the condition that two satellite systems have three visible satellites respectively, the position of the receiver can be acquired finally by using an algebraic processing method of a unary quadratic equation; and secondly, under the condition that the two satellite systems has seven or more visible satellites respectively, an observation equation set is converted into a linear equation set by using the redundancy of observation information, and a least square method is finally used to perform processing directly. The method needs no initial estimated value of a navigation position and also needs no iterated operation processing to ensure that the receiver can obtain a reliable positioning result during a deep space exploration and in other special environments.
Owner:BEIHANG UNIV
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