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50 results about "Nonlinear least squares optimization" patented technology

Method and system for calibrating inertial sensor by Doppler log

The invention discloses a method and system for calibrating an inertial sensor by a Doppler log, and relates to the technical field of underwater integrated navigation, and the method comprises the following steps: obtaining an IMU pre-integration factor and a DVL speed residual factor according to IMU observation data and DVL observation data; the method comprises the following steps: constructing a factor graph structure model by taking prior information of initial states of a gyroscope and an accelerometer as prior factors, taking the prior factors, an IMU pre-integration factor and a DVL speed residual factor as factor nodes, taking state variables of the gyroscope and the accelerometer as variable nodes and taking a relationship between the factor nodes and the variable nodes as edges; and correcting the state variables by using the factor graph structure model to obtain theoretical outputs of the gyroscope and the accelerometer after inertial navigation error compensation. Observed DVL data are used for carrying out online calibration on IMU errors, an underwater integrated navigation problem is modeled as nonlinear least square optimization, global optimal estimation of all-time state quantities is achieved, and the divergence speed of inertial navigation position errors is restrained.
Owner:SHANDONG UNIV

Unmanned aerial vehicle formation collaborative navigation method based on open information fusion architecture

The invention provides an unmanned aerial vehicle formation collaborative navigation method based on an open information fusion architecture, belongs to the field of unmanned aerial vehicle navigation, and aims to solve the navigation information fusion problem of asynchronous updating of multi-sensor data and available dynamic change of measurement information in a traditional formation collaborative navigation method. In the prior art, when asynchronous data fusion and measurement information availability change are coped, the defects of precision loss, poor flexibility and expansibility and the like exist. According to the method, a state variable and a measurement information set are constructed under an open architecture, a probability model of collaborative navigation state estimation is established based on Bayesian reasoning, and on this basis, a factor graph model is constructed by combining an incidence relation between a measurement model in posterior probability and prior information. By designing an independent measurement factor for each sensor, when sensor data is updated, flexible response to asynchronous data fusion and dynamic change of measurement information is realized by optimizing changed measurement factor nodes in real time and dynamically adding and deleting the nodes. And gradually minimizing an error cost function of each factor node through a nonlinear least square optimization method to realize efficient fusion of multi-sensor data and real-time updating of a navigation state. According to the method, the efficiency, flexibility and expansibility of asynchronous information fusion of the collaborative navigation system are remarkably improved, and reliable technical support is provided for unmanned aerial vehicle formation collaborative navigation.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Underground mine positioning and mapping trajectory optimization method based on underground control point constraint

The invention discloses an underground mine positioning and mapping trajectory optimization method based on underground control point constraint, and belongs to the field of positioning and mapping, and the method comprises the steps: respectively obtaining GNSS data, laser data, IMU data and image data; according to the GNSS data, the laser data, the IMU data and the image data, completing initialization of a laser radar-vision-inertial odometer system and GNSS initialization; extracting point cloud features of the distributed underground control points in real time based on an RANSAC algorithm, and generating a global coordinate constraint factor of nonlinear least square optimization; and performing relative attitude calculation according to the global coordinate constraint factor to complete underground mine positioning and mapping trajectory optimization. According to the method, the problems of accumulated error overrun and point cloud dislocation layering easily caused by pose drift in a special environment of an underground mine are solved.
Owner:CHONGQING INST OF GEOLOGY & MINERAL RESOURCES

Method for decoupling organic matter primary-secondary cracking hydrocarbon generation conversion rate based on gold tube hydrocarbon generation thermal simulation experiment

The invention relates to a method for decoupling organic matter primary-secondary cracking hydrocarbon generation conversion rate based on a gold tube hydrocarbon generation thermal simulation experiment. The method comprises the following steps: step 1, acquiring kerogen gold tube hydrocarbon generation thermal simulation experiment data; step 2, parametric modeling of the kerogen hydrocarbon generation process; step 3, constructing a least square target model under a multi-constraint condition; step 4, performing nonlinear least square optimization solution under the constraint condition; and 5, calculating the hydrocarbon generation conversion rate. According to the method, conversion rate calculation is carried out on the cumulant of each hydrocarbon generation process obtained through decoupling, the conversion rate evolution rule of the kerogen oil generation, gas generation, crude oil cracking gas generation, non-reactive carbon formation and other processes along with maturity change in the crude oil cracking process can be obtained, and a quantitative basis is provided for refined hydrocarbon generation evaluation.
Owner:SANYA MARINE OIL & GAS RESEARCH INSTITUTE NORTHEAST PETROLEUM UNIVERSITY

Cone beam computed tomography equipment correction method

The invention relates to the technical field of image correction of computed tomography equipment, in particular to a cone beam computed tomography equipment correction method, and aims to solve the problems that geometric parameters projected by existing CBCT equipment are inaccurate, and a three-dimensional image subjected to three-dimensional reconstruction has obvious artifacts. In order to achieve the purpose, the method comprises the following steps: acquiring position coordinates of a marking substance in a phantom coordinate system and projection coordinates of the marking substance on a flat panel detector coordinate system when a conical ray originates from a plurality of positions; based on the position coordinates and the projection coordinates, calculating a projection matrix when the conical ray originates from a plurality of positions; calculating an average internal reference matrix of the plurality of internal reference matrixes based on the plurality of projection matrixes; determining a calculation projection coordinate corresponding to the position based on the average internal reference matrix and the position coordinate; and a nonlinear least square optimization algorithm is adopted to minimize the distance error between the projection coordinates and the calculated projection coordinates, and a calibration projection matrix is obtained. Random errors are suppressed by calculating an arithmetic average of the plurality of internal reference matrices.
Owner:YINGNUO HIGH-TECH (SUZHOU) CO LTD

Battery SOC prediction method and system based on dynamic electrochemical impedance spectroscopy measurement

The invention discloses a battery SOC prediction method and system based on dynamic electrochemical impedance spectroscopy measurement in the technical field of lithium battery state prediction, and the method comprises the steps: superposing DIBS square wave signals as excitation current input on the basis of the main charging and discharging current of a battery, and collecting the voltage and current data of the battery in real time; according to the impedance spectrum, fitting a fractional order equivalent circuit model by adopting a nonlinear least square optimization method to obtain initial parameters of the fractional order equivalent circuit model; the initial parameters and voltage and current data collected in real time are input into a self-adaptive dual augmented extended Kalman filter, the main filter and the secondary filter operate cooperatively, state prediction and parameter prediction are executed alternately, and real-time synchronous prediction of SOC and fractional order equivalent circuit model parameters is achieved. The method is suitable for the SOC estimation requirement of the battery under the dynamic working condition, the working state of the battery does not need to be interrupted, and the method has good linearity, robustness and adaptivity.
Owner:NANJING INST OF TECH

Indoor local magnetic field modeling method and device based on magnetic source equivalence principle

The invention provides an indoor local magnetic field modeling method and device based on a magnetic source equivalence principle, and belongs to the technical field of indoor localization, and the method comprises the steps: collecting the data of a three-axis magnetometer in a space range through an array type magnetic sensor, and obtaining the original measurement information of an indoor magnetic field; based on a magnetic source equivalence principle, an indoor magnetic field is modeled into an equivalent magnetic dipole model consisting of a plurality of equivalent magnetic dipoles, and a magnetic field generated by the model is consistent with a real magnetic field in an observation area by setting magnetic moment and position parameters of the magnetic dipoles; according to the measured value of the array type magnetic sensor, an observation model is established in combination with an equivalent magnetic dipole model and used for describing the relation between the measured value and model parameters; through a nonlinear least square optimization method, parameters of the equivalent magnetic dipole model are solved according to the observation model, the equivalent magnetic dipole model of the indoor magnetic field is obtained, and the parameters comprise the magnetic moment and the position of the magnetic dipole. The precision and the reliability of the model are remarkably improved.
Owner:AEROSPACE INFORMATION RES INST CAS

Transient temperature field measurement method, system, equipment and medium

The invention relates to the technical field of non-contact temperature measurement, in particular to a transient temperature field measurement method, system and device and a medium, and the transient temperature field measurement method comprises the steps: synchronously collecting an original spectral signal and an original grayscale image of a transient temperature field; discretization processing is carried out on the corrected spectrum, a theoretical radiation spectrum corresponding to each temperature element is obtained, an image gray value-radiation brightness mapping relation is established, and temperature element weight initial distribution is obtained; optimizing by using an optimal solution algorithm to obtain an optimal temperature primitive weight; and inverting the temperature field by using the optimal temperature primitive weight and the histogram of the original grayscale image to obtain a final fusion image of the transient temperature field. According to the method, the dynamic reconstruction of the two-dimensional temperature field of the explosion fireball is realized by constructing the temperature primitive model and combining nonlinear least square optimization and image mapping of the image detector, and the problems of large single-point inversion error and low spatial resolution of the transient high-temperature field are solved.
Owner:CHANGCHUN UNIV OF SCI & TECH

Pseudo-range prediction correction-based factor graph optimization Beidou inertial navigation positioning method and system

The invention discloses a Beidou inertial navigation positioning method and system based on pseudo-range prediction correction factor graph optimization, and the method comprises the steps: obtaining observation feature data and inertial navigation data, and constructing a current navigation state vector of a vehicle; according to the signal state of the Beidou satellite navigation system, training a reinforcement learning model through observation characteristic data and inertial navigation data, and determining a pseudo-range value; according to a factor graph optimization method, introducing a pseudo-range value as an observation factor, and converting a navigation state vector of the vehicle at the current moment into a multi-factor constrained optimal problem; and carrying out global optimal state sequence solution on the multi-factor constrained optimal problem through a Levenberg-Marquardt algorithm by adopting nonlinear least square optimization, so as to obtain a positioning estimation result of the vehicle. According to the invention, dynamic complementation and intelligent cooperation of Beidou and inertial navigation information can be realized, and the precision of positioning estimation is improved. The Beidou inertial navigation positioning method and system based on pseudo-range prediction correction factor graph optimization can be widely applied to the technical field of satellite positioning.
Owner:GUANGDONG UNIV OF TECH

Power system abnormity identification method and system based on mechanism model and artificial intelligence

The invention provides an electric power system abnormity identification method and system based on a mechanism model and artificial intelligence, and belongs to the technical field of electric power system safety. Comprising the following steps: constructing a steady-state model according to a power grid branch power balance and node energy conservation relationship, calculating a power balance deviation of a time sequence by using the steady-state model, marking each data point according to whether the power balance deviation exists or not, and forming a prior data set; extracting data points which are judged to have no balance deviation to form a primary detection data set, and constructing a Bayesian-Kalman fusion detection model to perform primary detection on the primary detection data set; extracting data points judged as non-abnormal data to form a secondary detection data set, constructing an FCM-GEP detection model, and performing secondary detection on the secondary detection data set; and fusing the two detection models into an abnormal data detection function through an unconstrained nonlinear least square optimization method, wherein the abnormal data detection function is used for continuously acquiring a prior data set in real time to carry out supplementary detection on non-abnormal partial data.
Owner:ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID NINGXIA ELECTRIC POWER COMPANY +1

Regional navigation positioning method, system and equipment based on sequential information and medium

The invention provides a regional navigation positioning method, system and device based on sequential information, and a medium, which can effectively improve the positioning precision and reduce the calculation complexity when processing the sequential information, and have better precision and robustness. Under a satellite navigation denial condition, aiming at distance measurement information at different moments obtained by land-based radio area navigation, a factor graph model is established to represent an information transmission process between different moment states of a positioning target. Compared with a traditional Kalman filtering framework, the factor graph algorithm is better in positioning precision, higher in flexibility, lower in calculation complexity and better in robustness when sequential information is processed. According to the method, state estimation is converted into a nonlinear least square optimization problem, a Gaussian Newton method is adopted for iterative solution, and compared with extended Kalman filtering, the matrix operand is reduced by more than 40%.
Owner:BEIJING INST OF TECH

A node machining review and precision improvement method based on three-dimensional laser scanning

The application discloses a node processing review and precision improvement method based on three-dimensional laser scanning, relates to the technical field of digital manufacturing and steel structure engineering precision control, and comprises the following steps: through multi-scale structure feature identification, basic attributes and topological relationship modeling are combined, effective guidance of design information to the whole detection process is realized, through enhanced feature tree driven scanning path planning combined with multi-view point cloud fine splicing strategy, the collaborative mechanism of scanning implementation and design features is embodied, high-quality data acquisition of key functional features is realized, through multi-scale feature corresponding set construction combined with an adaptive nonlinear least square optimization model, the idea of multi-level constraint collaborative participation registration is embodied, high-stability rigid body transformation solution is realized, through deviation field construction combined with function area confidence and effective error index calculation, the ability of detection result transformation to engineering decision is embodied, and the scientificity of correction and rework decision is improved.
Owner:JIANGSU SAIMU TECH CO LTD

Underwater robot trajectory tracking method and related device

The invention discloses an underwater robot trajectory tracking method and a related device, and relates to the technical field of underwater robot autonomous navigation, and the method comprises the steps: synchronously collecting the original data of an underwater robot camera, an IMU and a DVL; performing time synchronization on IMU and DVL data by taking a camera timestamp as a reference, and converting DVL speed data into an IMU coordinate system; calculating a relative translation vector and a time interval based on the relative pose transformation matrix of the adjacent key frames, and determining an average speed estimation value of the underwater robot between the adjacent key frames; comparing the average speed estimation value with the actual measurement speed of the DVL, and determining a speed error function of the DVL; and constructing a weighted error cost function containing visual re-projection, IMU pre-integration and DVL speed error terms, solving optimal estimation of key frame poses and map point states through nonlinear least square optimization, and outputting an optimized trajectory of the underwater robot. According to the invention, the precision of trajectory tracking of the underwater robot is effectively improved.
Owner:BEIJING INST OF TECH

Control moment gyroscope implicit parameter tracking method based on two-stage identification

The invention discloses a control moment gyroscope implicit parameter tracking method based on two-stage identification, and belongs to the technical field of spacecraft execution mechanism health monitoring and fault diagnosis. According to the method, through four core steps of electromechanical coupling model establishment, first-stage sliding window batch NLS coarse identification, Wiener process degradation modeling and second-stage adaptive EKF fine correction, a complete process from electrical telemetry data to implicit parameter accurate identification is realized. The method comprises the following steps: constructing a mapping relation between an electrical signal and an implicit parameter based on an SKF friction torque model and a direct current brushless motor voltage equation, and obtaining a preliminary implicit parameter value through nonlinear least square optimization by using electrical measurement data in a sliding time window; a nonlinear drift Wiener process is adopted to describe the evolution rule of hidden parameters along with time, and a first-stage result serves as an observation value and is subjected to smooth correction through extended Kalman filtering; according to the method, through a two-stage framework design of combining a sliding window batch NLS with a Wiener process driven adaptive EKF, the interpretability of a physical model and the sequence modeling capability of a random process are fully combined, working condition interference and parameter degradation information are effectively decoupled, noise interference of an identification result is remarkably reduced, and the degradation trend of equipment is accurately tracked. According to the method, the problems of serious electromechanical coupling interference, insufficient parameter identification precision, poor degradation trend tracking capability and the like in the existing CMG health monitoring technology are solved, reliable technical support is provided for health management and life prediction of the single-frame control moment gyroscope, and the reliability and safety of a spacecraft attitude control system are remarkably improved.
Owner:BEIHANG UNIV

Method and system for calibrating inertial sensor of Doppler odometer

The present invention discloses a method and system for calibrating an inertial sensor using a Doppler odometer, relating to the technical field of underwater integrated navigation. The method comprises: obtaining an IMU pre-integration factor and a DVL velocity residual factor based on IMU observation data and DVL observation data; constructing a factor graph structure model using prior information of the initial states of a gyroscope and an accelerometer as prior factors, the prior factors, the IMU pre-integration factor, and the DVL velocity residual factor as factor nodes, the state variables of the gyroscope and accelerometer as variable nodes, and the relationships between the factor nodes and the variable nodes as edges; and obtaining theoretical outputs of the gyroscope and accelerometer after inertial navigation error compensation by correcting the state variables using the factor graph structure model. The IMU error is calibrated online using observed DVL data, and the underwater integrated navigation problem is modeled as a nonlinear least squares optimization method to achieve a global optimal estimation of the state quantity over the entire time period and suppress the divergence rate of the inertial navigation position error.
Owner:SHANDONG UNIV

Engine online adaptive model predictive method based on reduced dimension kalman filter

The application provides an online adaptive model prediction method for an engine based on dimension reduction Kalman filtering, which comprises the following steps: S1, obtaining a state space equation of the engine; S2, performing dimension reduction on a health parameter by using a dimension reduction matrix V to obtain a state space equation after dimension reduction of the parameter; S3, performing offline optimization on the dimension reduction matrix V by using a nonlinear least square optimization algorithm to obtain an optimal dimension reduction matrix V; and S4, estimating and predicting the health parameter of the engine and an output vector of the engine by using a dimension reduction Kalman filtering algorithm to obtain a real-time updated and optimized health parameter, and substituting the real-time updated and optimized health parameter and the optimal dimension reduction matrix V into the state space equation of the engine to obtain a state space equation with minimum dimension reduction error and adaptive adjustment of the health parameter, namely, an adaptive estimation model of the engine. The application can give the best health parameter of the variable cycle engine according to the current working state of the engine by using the dimension reduction Kalman filtering algorithm.
Owner:BEIJING POWER MACHINERY INST

Fuzzy neural network fitting method and device, equipment and storage medium

The invention provides a fuzzy neural network fitting method and device, equipment and a storage medium, and the method comprises the steps: initializing a network structure and parameters of an input layer, a fuzzy layer, a hidden layer and an output layer; a forward propagation process is executed, the training data of the input layer is fuzzified through the fuzzy layer and then transmitted to the hidden layer, a forward propagation result is calculated through the output layer, and a loss function is calculated; a back propagation process is executed based on the loss function, a gradient of parameter updating is obtained through layer-by-layer transmission, parameters are updated by using an LM nonlinear least square optimization algorithm, and a fuzzy neural network after fitting is completed is obtained after iteration is finished; and evaluating the performance of the fuzzy neural network. According to the method, the expression ability of uncertainty and fuzziness of the input data is enhanced by utilizing fuzzification processing; the LM algorithm is introduced to optimize the weight and bias, and the training speed can be remarkably increased while the convergence stability is kept.
Owner:CHINA ACAD OF AEROSPACE AERODYNAMICS

Scene-dependence-free external parameter calibration method and system for rotary laser radar and inertial navigation

A scene-dependence-free external parameter calibration method for a rotary laser radar and inertial navigation comprises the following steps: constructing a kinematic model between the laser radar and a motor by adopting a modeling method based on DH parameters; the method comprises the following steps: extracting first plane feature information in an environment, constructing a kinematic model in combination with an optimization strategy to carry out nonlinear least square optimization, and obtaining a pose transformation matrix of a laser radar under a motor coordinate system as a first external parameter; obtaining an initial pose sequence through a laser radar odometer; an objective function is constructed based on inertial navigation pre-integration information and plane constraints, and a pose transformation matrix of the motor and inertial navigation is obtained and serves as a second external parameter; and obtaining a pose change relation between the laser radar and the inertial navigation through a chain type combination relation of coordinate transformation, the first external parameter and the second external parameter. The method does not need to depend on other external scene data for external parameter expression, can achieve the calibration of the rotary laser radar and inertial navigation external parameters at any position, and is more practical.
Owner:GUANGDONG UNIV OF TECH +1

Multi-camera joint calibration method without common view, medium and device

The present application relates to a kind of multi-camera joint calibration method without public view, medium and equipment, by collecting the several two-dimensional images of several ball calibration targets and target tracking instrument conversion matrix;Several three-dimensional point clouds of calibration ball and ball center coordinates are collected;The ball center coordinates of robot end calibration ball and corresponding flange pose under tracking instrument coordinate system are collected;Two-dimensional ball center coordinates in each two-dimensional image are extracted, and three-dimensional ball center coordinates are converted to obtain the external parameter of each 2D camera;According to the coordinates of the ball center of each calibration ball, the external parameter of each 3D camera is solved;Space transformation closed loop equation is constructed;Linear solution of end tool parameter and robot base external parameter is solved, and linear solution is used as initial value to construct the nonlinear least square optimization problem with the goal of minimizing space transformation closed loop equation residual, and the optimal solution of end tool parameter and robot base external parameter is solved, and calibration is completed.Thereby the problem of high-precision collaborative work of multi-source sensor in complex intelligent manufacturing scene is improved.
Owner:SPEEDBOT ROBOTICS CO LTD

GNSS and laser odometer coupled positioning method based on factor graph sliding window

The invention relates to the technical field of aircraft and robot navigation, and discloses a GNSS (Global Navigation Satellite System) and laser odometer coupled positioning method based on a factor graph sliding window, which comprises the following steps: acquiring original observation data of a GNSS and converting the original observation data into a northeast ENU coordinate system; obtaining original observation data of the laser radar and an inertial measurement unit IMU, and calculating through a laser inertial odometer LIO algorithm to obtain a relative pose transformation sequence at adjacent moments; constructing a factor graph; setting a sliding window; triggering one-time nonlinear least square optimization at a preset time interval; and updating a rotation translation transformation matrix from the laser odometer coordinate system to the ENU coordinate system in real time according to an optimization result. According to the invention, the efficiency of fusion calculation and the fusion error of the laser speedometer are greatly reduced by setting a factor graph sliding window and optimization time, the overall calculation amount is small, and the real-time performance is high; meanwhile, a conversion matrix from the laser speedometer to the ENU system is estimated in real time, and long-time accurate recursion after the GNSS fails is ensured.
Owner:四川中科友成科技有限公司

An unmanned aerial vehicle low-altitude visual navigation method based on motion blur assistance

The present application relates to a kind of unmanned aerial vehicle low-altitude visual navigation method based on motion blur auxiliary, comprising: acquisition monocular camera image and IMU data, quantification the image blur degree of the monocular camera image, to extract the blur parameter of dominant motion, for calculating global measurement blur data;The IMU data is pre-integrated, obtains the relative motion amount between adjacent frames, and based on system prior state estimation, the image plane motion field of current time is predicted, for simulating global theoretical blur data;The global measurement blur data and the global theoretical blur data are compared, and after being combined with adaptive weight, as motion blur consistency error, construct nonlinear least squares optimization objective function;According to the nonlinear least squares optimization objective function, Gauss-Newton method iteration is solved, generates the state vector of minimum total error, for calculating health score, to implement three-level mode switching.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Rainfall spatiotemporal generation method and system based on rainfall weighted flow distance

The application discloses a watershed space-time rainfall generation method and system based on rainfall weighted flow distance, comprising the following steps: calculating the distance from each rainfall station to the drainage outlet in a watershed, and performing normalization processing; constructing a rainfall weighted distance constraint in any time period; converting the constraint relationship into a nonlinear least square optimization problem; solving the optimization problem by using a sequential quadratic programming algorithm; repeating the optimization process for all time periods to obtain a watershed rainfall proportion matrix, wherein the watershed rainfall proportion matrix is used for representing the proportional distribution relationship of a rainfall process at different rainfall stations and in different time periods. The application can flexibly generate various rainfall distribution scenarios under the condition of meeting specific rainfall space-time index constraint conditions, so as to quantitatively analyze the influence of rainfall center movement on urban flood process.
Owner:BEIJING UNIV OF TECH

Dynamic identification method and system for GFM inverter dominant power distribution system and related device

The invention provides a dynamic identification method and system for a GFM inverter dominant power distribution system and a related device. The method comprises the following steps: step 1, establishing a phasor domain mathematical model of a GFM inverter in a phasor domain; step 2, constructing a nonlinear least square optimization model based on the phasor domain mathematical model, obtaining a parameter estimation value corresponding to the GFM inverter, substituting the parameter estimation value into the phasor domain mathematical model, and solving to obtain an optimized output phasor; step 3, optimizing a system dynamic prediction model pre-constructed based on the NARX neural network by using the optimized output phasor obtained in the step 2 to obtain an optimized system dynamic prediction model; and step 4, based on the pre-constructed equivalent model of the GFM inverter in the phasor domain, utilizing the optimized system dynamic prediction model obtained in the step 3 to dynamically predict the dominant power distribution system of the GFM inverter, and through organic combination of physical optimization and data driving, high-precision and high-generalization system dynamic representation is realized.
Owner:XIAN THERMAL POWER RES INST CO LTD

Constraint vector fitting system and method fusing sharing and local pole structure

The invention discloses a constraint vector fitting system and method fusing a shared pole structure and a local pole structure, designs a novel VF structure, introduces mixed pole configuration combining a shared pole and a local pole, and can maintain high-quality fitting of a Y parameter even in the presence of a loading phase. Therefore, the sensitivity of fitting precision to phase distortion is reduced; through post-processing identification of the model and iterative elimination of phase contributions corresponding to local poles and linear terms, compatibility with a traditional VF is ensured; in consideration of the characteristic that the VF mainly solves the residual error, the constraint on the number of transmission zeros is reconstructed into a group of linear constraints on the residual error, so that the problem can still be solved in the VF framework; in addition, a nonlinear residual constraint proposed in a physical realizability requirement is formalized into a nonlinear least square optimization problem to be introduced into a fitting process; the VF problem with physical constraints is solved by adopting an augmented Lagrange method ALM, and unified balance of fitting precision and physical consistency is realized.
Owner:XIDIAN UNIV

SFG spectrum advanced fitting analysis method and system

The invention discloses an advanced fitting analysis method and system for an SFG spectrum. The method comprises the following steps: after preprocessing original SFG spectral data, automatically generating an initial amplitude and a central position of a Gaussian peak in combination with data local maximum intensity within a specified search tolerance range according to a predefined peak group and a nominal center of a target peak; fitting the spectral data by using a multi-Gaussian function model and a nonlinear least square optimization algorithm to obtain fitting parameters of each Gaussian peak; refining and combining Gaussian peak parameters after successful fitting; automatically identifying and calculating the intensity of a specific key characteristic peak; and generating a detailed SFG spectrum fitting graph and a fitting parameter report. According to the method, accurate, stable and automatic deconvolution and quantitative analysis of the SFG spectrum are realized, and objective and repeatable data with deep physical and chemical significance is provided for the fields of material science, surface chemistry and the like.
Owner:SOUTHEAST UNIV

Positioning method and system based on GNSS interference detection and assistance

The invention discloses a positioning method and system based on GNSS interference detection and assistance, and the method comprises the steps: obtaining original ADS-B data, and carrying out the data preprocessing, and obtaining the preprocessed ADS-B data; performing abnormal flight fluctuation sequence identification processing on the preprocessed ADS-B data based on a deep learning model to obtain interference flight data; performing cluster calculation on the interference flight data through an interference positioning algorithm to obtain a preliminary interference source coordinate; and based on the initial interference source coordinates, an interference source positioning problem is converted into a nonlinear least square optimization problem and is solved, and accurate interference source coordinates are obtained after destandardization. According to the invention, the GNSS interference searching cost can be reduced, and the GNSS interference source positioning precision can be improved. The positioning method and system based on GNSS interference detection and assistance can be widely applied to the technical field of satellite assisted positioning.
Owner:SHENZHEN UNIV

Phase unwrapping method based on factor graph

The invention aims to provide a phase unwrapping method based on a factor graph, which comprises the following steps of: A, cutting an interferogram into a plurality of sub-interferograms with the same size by adopting a coincidence cutting mode, and reserving a plurality of rows or columns of overlapped pixels between adjacent sub-interferograms during cutting; b, constructing a phase unwrapping system equation for each sub-interferogram, then constructing a corresponding phase unwrapping factor graph model formula, and finally converting a factor graph optimization problem into a nonlinear least square optimization problem; C, carrying out iterative solution on the nonlinear least square optimization problem by adopting a Lescenberg-Marquardt method to obtain a nonlinear least square optimization problem; obtaining an unwrapping phase result of each sub-interferogram; and D, combining the unwrapping results of the sub-interferograms by using an unwrapping phase consistency criterion of adjacent regions of the interferograms to obtain an unwrapping phase of the whole interferogram. According to the phase unwrapping method, the consistency and the stability of a phase unwrapping result are improved.
Owner:GUANGXI UNIVERSITY OF TECHNOLOGY

An underground online joint calibration method

The present invention relates to an underground online joint calibration method, belonging to the field of underground detection technology. The method comprises obtaining anchor net image data collected by an industrial camera and anchor net point cloud data collected by a laser radar; extracting the first edge contour of the anchor net from the anchor net image data using an image processing method; extracting the second edge contour of the anchor net from the anchor net point cloud data using a point cloud processing method; performing a coarse matching of the first edge contour and the second edge contour based on a particle swarm search method of longhorn beetle whiskers; and performing a precise matching of the first edge contour and the second edge contour, specifically: taking measurement errors into account, constructing a line-to-line ICP problem, and performing nonlinear least squares optimization to solve the optimal external parameters and obtain a calibration result. During the matching process, it is easy to fall into a local optimal solution. The particle swarm search method of longhorn beetle whiskers can prevent the local optimal solution, thereby reducing the number of searches and ensuring that the local optimal solution will not be fallen into.
Owner:TAIYUAN UNIVERSITY OF TECHNOLOGY

Battery internal short circuit quantitative detection method and system based on multi-multiple discharge difference

The application provides a battery internal short circuit quantitative detection method and system based on multi-multiple discharge difference, comprising the following steps: S1, constructing an improved Peukert equation suitable for internal short circuit batteries; S2, constructing a nonlinear least square optimization model for parameter identification of the improved Peukert equation; S3, comprehensively considering battery test time consumption and internal short circuit detection accuracy to obtain an optimal discharge combination; S4, performing online multi-multiple discharge test on a battery to be detected based on the optimal discharge combination to obtain test data; and S5, combining the test data and the improved Peukert equation to quantitatively evaluate the internal short circuit resistance value of the battery. The improved Peukert equation realizes quantitative expression of the relationship between the constant current discharge current and the electric quantity of the battery under the internal short circuit condition by fusing the internal short circuit leakage characteristics and the multi-multiple discharge law of the battery.
Owner:SHANGHAI JIAOTONG UNIV

Motion track planning method for image motion compensating mirror of photoelectric search system

The invention discloses a motion track planning method for an image motion compensating mirror of a photoelectric search system. The method comprises the following steps: establishing a perfect image motion compensation angle mathematical model according to technical indexes of a photoelectric search system by considering a geometrical relationship that a rotation center of a compensation mirror is not overlapped with a reflecting surface; based on the perfect image motion compensation angle mathematical model, constructing a theoretical angular displacement mathematical model of the compensating mirror in a complete sweep period; a sine function is adopted to construct an approximate mathematical framework of the global motion trail; the angular displacement data of the detector within the integration time is taken as the reference, and the sine function amplitude is optimized and fitted through a nonlinear least square method, so that the sine trajectory is enabled to approach the theoretical trajectory with the minimum error within the integration time; and taking the optimized sine track as an input instruction of an image motion compensating mirror control system. According to the method, image motion compensation precision is guaranteed, smooth motion is realized, and rigid or flexible impact is avoided. Besides, even if the sine amplitude has deviation, the introduced angle additional error is still within the system tolerance, the robustness is good, and the method is suitable for a high-precision and high-dynamic photoelectric searching and tracking system.
Owner:CHENGDU UNIV