185results about How to "Improve numerical stability" patented technology

The invention relates to an electric network parameter estimation method based on the parameter sensitivity of a state estimation residual error, which belongs to the technical field of electric network parameter identification of electric power systems. The electric network parameter estimation method comprises the following steps: deducing the sensitivity of the state estimation residual error for each circuit parameter of an electric network according to an actual electric network model and real-time measuring data; and modifying the circuit parameter on the prior suspicious branch circuit by adopting a linear optimization method, thereby increasing the reliability and the accuracy of application software. The electric network parameter estimation method based on the parameter sensitivity of the state estimation residual error does not have the problems of numerical stability and observation performance and has simple calculation, easy realization and high calculation speed.

The invention discloses a CT imaging system and a method. The method includes: conducting common CT scanning on an object to obtain a common CT image, then determining an area-of-interest in the image, making use of a photon counting detector to perform CT scanning on the area-of-interest from multiple energy windows, and then re-establishing a high resolution image of the area-of-interest. The photon counting detector is employed to collect the photon counting projection data of multiple energy windows, so that decomposition of multiple basis functions can be carried out, the energy spectrum can have high discrimination, and the numerical stability can be good.

The invention belongs to the field of signal processing, and particularly relates to a DOA (Direction of Arrival) estimation method through second-order statistics reconstruction based on matrix completion. Based on the matrix completion theory, the DOA estimation method through second-order statistics reconstruction based on matrix completion is put forward. Firstly, based on the matrix completion method, an elastic regularization factor is introduced to reconstruct a received signal covariance matrix to a noise-free covariance matrix; under the second-order statistics domain, through matrixsummation averaging, a multi-vector problem of the noise-free covariance matrix is converted to a single-vector problem; and finally, a sparse reconstructed weighted l1 norm is used to realize DOA parameter estimation. Non-uniform noise influences can be significantly suppressed, the DOA parameter estimation performance is good, and in a condition of a low signal-to-noise ratio, the provided algorithm has high angle estimation precision and high resolution.

The invention discloses a power system interharmonic estimation method based on an auto-regression (AR) model and Kalman filtering, relates to an interharmonic estimation method and aims to solve the problems the conventional fast Fourier transform method has poor real-time property and the conventional Burg algorithm has low spectral analysis performance and low anti-jamming capability. The method comprises the following steps of: A, acquiring signal data of a power system; B, establishing an autoregressive (AR) model according to the acquired signal data of the power system, and analyzing the signal of the power system by utilizing the AR model; C, establishing a state equation and an observational equation; D, determining the order of the AR model according to a final prediction error rule; E, estimating parameters of the AR model on line by utilizing an adaptive Kalman filtering method; and F, performing power spectrum estimation by using the AR model, and substituting the optimal estimated value into an AR model power spectrum density formula for power spectrum estimation. The method is used for estimating the power spectrum of power system interharmonics.

A calibration method based on star field for the star-sensitive sensor includes such steps as creating a posture conversion array of star-sensitive sensor, creating the distortion model of star-sensitive sensor, and eliminating the least square parameters.

The invention discloses a linear integer planning method of power distribution network on-line breakdown fault-tolerant location. The method includes the following steps that: an independent power distribution region and a related equipment set of the independent power distribution region are established; layered decoupling numbering is performed on the independent power distribution region, and a cause and effect equipment set is established; current alarm information is collected, a switching function set is established; an absolute value model of power distribution network breakdown location is established, and an equivalent linear integer planning breakdown location model can be established, and a feeder breakdown section is located through 0-1 linear integer planning; and the isolation of the feeder breakdown section is realized through the location result of the feeder breakdown section. According to the method of the invention, the dependence of a logic relationship modeling-based optimized fault location method on a swarm intelligence algorithm can be gotten rid of; and the conventional 0-1 linear integer planning is adopted to realize the location of the feeder breakdown section. The method is suitable for closed-loop open-loop-operation large-scale power distribution network online breakdown location. The method of the invention has the advantages of convenience, high reliability, high fault tolerance capability, high breakdown location efficiency, high adaptability for multiple breakdowns and the like.

The invention discloses a phasor measurement unit (PMU) measurement data-based power line parameter identification and estimation method, and belongs to the technical field of power system line parameter identification and estimation. The method comprises the following steps of: inputting basic data of an identified and estimated line by using a computer through a program, identifying error parameters of the line according to the PMU measurement data of multiple time intervals at two ends of the line, and estimating accurate parameters of the line to acquire estimation values of the accurate parameters of the line. A mean value-based identification index and parameter estimation method is constructed by using the PMU measurement data of multiple time intervals at two ends of the line, anda variance coefficient is used as a convergence precision criterion; and the method is simple, has good identification effect, high estimation precision and high calculation speed, and is convenient for popularization and application. The method can be widely applied to identification and estimation of the centralized parameters of the power line, the two ends of which are provided with PMUs; andthe method is particularly suitable for identification and estimation of the parameters of medium length high-voltage and ultrahigh-voltage power transmission lines.

The invention discloses a meshless RKPM-based two-dimensional thermal deformation and stress analysis method for an anisotropic material structure. The method mainly comprises the following steps of (1) performing RKPM node discrete preprocessing on a calculation model; (2) solving an RKPM thermal deformation displacement value: assembling RKPM overall force stiffness matrix and overall thermal load column vector; applying a boundary, and processing a first boundary condition by adopting a penalty function method; establishing a meshless RKPM thermal stress discrete control equation of the anisotropic material structure, and solving the RKPM thermal deformation displacement parameter value of a node; (3) solving an RKPM thermal stress value: performing approximation on the obtained thermaldeformation displacement parameter value by adopting reproducing kernel approximation to calculate out a thermal stress of a Gaussian point, thereby obtaining the RKPM thermal stress value of the node; and (4) post-processing a calculation result. The two-dimensional thermal deformation and stress analysis of the anisotropic material structure is performed based on a meshless RKPM; and a numerical method is stable and high in precision.

An embodiment of the invention provides an electric-power-system robust state estimation method based on a subsection nonlinear weight function and an apparatus thereof. The method comprises the following steps of constructing a node admittance matrix of an electric power system, a measurement amount measurement equation and a zero injection equality constraint; calculating a jacobian matrix and a measurement-amount residual error of the electric power system and acquiring a weight of each measurement amount; and updating a state variable, determining whether an iteration algorithm reaches a convergence threshold, and if the iteration algorithm reaches the convergence threshold, acquiring a final node voltage amplitude and a phase position of the electric power system. In the invention, bad data detection and identification, and state estimation are simultaneously performed; state estimation calculating is performed, and simultaneously a measurement amount weight can be changed; a bad data weight in iteration is continuously reduced and an influence brought by the bad data is restrained; a calculation amount is effectively reduced and work efficiency is increased; a residual error of the measurement amount is directly introduced into a subsection nonlinear weight function, and standardized residual error calculating is avoided so that a calculating speed can be greatly increased and calculating time is saved; and the method and the apparatus are suitable for an engineering application.

The present invention relates to an accurate registration method of multi-frame depth image. Said method includes the following steps: (1), judging boundary point, noise point and isolated point so as to remove point whose noise is large; (2), selecting reference point in overlay area of different depth images, creating correspondent point buffer zone for every reference point so as to search correspondent point in buffer zone; and (3), adopting iteration method to progressively optimize whole registration accuracy. Said invention also provides the concrete steps of said iteration method.

The invention discloses a lithium-ion battery SoC (State-of-Charge) estimation method based on improved and self-adaptive dual unscented-Kalman-filters. The method mainly comprises the following steps: 1) establishing a state filter and a parameter filter of a lithium ion power battery based on an equivalent circuit model; 2) coupling the state filter and the parameter filter of the lithium ion power battery based on the equivalent circuit model, and building dual unscented-Kalman-filters; and 3) inputting operation parameters of a to-be-detected lithium ion power battery into the dual unscented-Kalman-filters, and carrying out parameter correction and stage-of-charge (SoC) estimation on a lithium ion power battery equivalent circuit model. According to the method in the invention, the effectiveness of cholesky decomposition is guaranteed, the problem that iteration is stopped due to the fact that a covariance matrix is indefinite caused by reasons such as an initial value error, noisedisturbance, calculation module floating point error and the like is overcome, and the numerical stability of the filtering process and the robustness of the algorithm are enhanced.

The invention provides a fluid simulating method and device. The method includes the steps that firstly, a mixed flow model is constructed; secondly, smoothed particle hydrodynamics (SPH) particles are constructed; thirdly, relevant information of fluid needed by the mixed flow model is processed in the mixed flow model through an SPH method; fourthly, information needed in fluid simulating is output according to a processing result in the mixed flow model. According to the fluid simulating method and device, the moving process of multi-component fluid can be widely and accurately simulated.

The invention discloses a FastSLAM method based on particle proposal distribution improvement and adaptive particle resampling. The method comprises the steps that 1, a square root transformation unscented Kalman filter is utilized to estimate optimal particle proposal distribution, and the pose state of a robot is sampled; 2, a square root volume Kalman filter is utilized to update feature map information corresponding to each particle; 3, an adaptive particle resampling method based on relative entropy is utilized to determine the quantity of particles needed at the current moment; 4, the pose stat of the robot and guidepost feature map information are determined according to a particle set obtained after resampling. A traditional FastSLAM algorithm is improved from the two aspects of quality and quantity of the sampling particles at the same time, thus, the numerical stability and accuracy of the algorithm in the estimation process are enhanced, and the quality of the sampling particles is improved; in the particle resampling process, the least quantity of the needed particles is dynamically determined according to estimation uncertainty, and therefore the calculation efficiency of the algorithm is improved.

The invention discloses a cubic spline-based infrared thermal image blind pixel compensation algorithm, which comprises the following steps of: obtaining a blind pixel distribution map of an infrared thermal image by blind pixel detection; for each blind pixel point, constructing cubic splines of a row direction and a column direction in a way of taking coordinates of pixels in a row and a column where the blind pixel is in the infrared thermal image as interpolation nodes respectively, calculating interpolated values of the two cubic splines at the blind pixel point respectively, and taking a mean value of the two interpolated values as a primary compensation value of the blind pixel; after all the blind pixels in the infrared thermal image are subjected to the primary compensation, performing secondary compensation on the blind pixels; for each blind pixel point, constructing the cubic splines of the row direction and the column direction in a way of taking the coordinates of the pixels in the row and the column where the blind pixel is and the coordinates of the other blind pixels subjected to the primary compensation in the infrared thermal image as the interpolation nodes respectively, calculating the interpolated values of the two cubic splines at the blind pixel point respectively, and taking the mean value of the two interpolated values as a secondary compensation value of the blind pixel; and traversing all the blind pixels in the infrared thermal image to obtain the infrared thermal image subjected to the secondary blind pixel compensation.

The invention provides a seismic-wave motion equation generating method and a system thereof. The seismic-wave motion equation generating method comprises: obtaining acoustic wave equation data; obtaining geological parameter information; executing arbitrary difference precise integration according to the acoustic wave equation data and the geological parameter information so as to get the seismic spread equation; obtaining the stability condition, the initial input condition and the boundary processing condition; and generating the seismic-wave motion equation by the seismic spread equation, the stability condition, the initial input condition and the boundary processing condition. The method has higher precision and better value stability, can greatly improve the precision and the stability of the calculation with hardly additional computational complexity. The completely matching layer boundary condition which is obtained according to the arbitrary difference precise integration plays a fine attenuating role in the boundary reflection. The method can provide the seismic-wave spread rule study in complex region with a high-precision data system with fine stability.

The invention discloses a method for estimating the state of a three-phase four-wire low-voltage distribution network and belongs to the technical field of three-phase state estimation of distribution networks. The method comprises the following steps of firstly, by using a computer, inputting low-voltage distribution meter-reading electric data and a network structure which are acquired within any time section, and parameter information through a program, and initiating the data, the network structure and the parameter information; then calculating constant item parts of a node admittance matrix and a jacobian matrix; synthesizing a measuring equation and T-end point zero injection equation restriction, and taking a real part and an imaginary part of voltage as state variables to calculate unbalance amount, an index type weight function and the jacobian matrix; finally updating the state variables and performing astringency judgment to realize estimation on the state of the three-phase four-wire low-voltage distribution network. Active power and reactive power of a node can be independently calculated by the method, the adverse influence of bad data on an estimating result is prevented, and the method has the characteristics of high difference resistance, good astringency, good numerical stability and the like. The method is widely applied to the estimation on the state of the three-phase four-wire low-voltage distribution network.

The invention discloses a high-precision real-time stereoscopic visual positioning method utilizing the parallax space bundle adjustment. According to the invention, only a video streaming obtained by a stereo camera is utilized to carry out navigation positioning of a mobile robot, so that the high-precision real-time stereoscopic visual positioning method has complete autonomy; a U-SURF descriptor is utilized to carry out feature matching, so that the high-precision real-time stereoscopic visual positioning method has strong robustness on illumination variation, motion blur and large rotation and scale variation which are generated in the moving process; and due to the utilization of a parallax space bundle adjustment optimizing method, an autonomous navigation vehicle can also be subjected to accurate real-time positioning when traveling for a long distance, so that the high-precision real-time stereoscopic visual positioning method has the advantages of low degree of dependence on an optimal initial value, high convergence rate, high value stability and the like and compared with a stereoscopic visual positioning method utilizing the bundle adjustment, the high-precision real-time stereoscopic visual positioning method has higher positioning precision and higher speed. The integral stereoscopic visual positioning method disclosed by the invention has high calculating speed and can be operated on line in real time.

The invention discloses a parameter estimation method for an electric power circuit in T-type connection, which belongs to the technical field of parameter identification and estimation for circuits of power systems. A computer and data acquisition devices at three ends of the circuit in T-type connection are adopted, SCADA (supervisory control and data acquisition) measured data for the circuit in T-type connection under a plurality of load levels at multiple time intervals are imputed by the aid of a program, then a weighted least squares estimation model is solved to obtain estimated values of parameters of the circuit in T-type connection under one load level, namely a sample of estimation values, then a mean value of a plurality of samples of estimation values is calculated, coefficient variations of the samples are used as convergence tolerance of parameter estimation precision, and finally estimation values of the parameters of the circuit in T-type connection are obtained. By the aid of the parameter estimation method, the parameters of the circuit in T-type connection can be effectively estimated, and the parameter estimation method has the advantages of simplicity, quickcalculation speed, high estimation precision, good stability of data, high engineering practicality, convenience in popularization and application, and the like. In addition, the parameter estimationmethod can be widely applied to parameter estimation of optional electric power circuits which are in T-type connection and are provided with data acquisition devices.

The invention provides a magnetic-control bias momentum satellite attitude control method based on the periodic Lyapunov equation, and relates to a magnetic-control bias momentum satellite attitude control system. The magnetic-control bias momentum satellite attitude control method based on periodic Lyapunov equation solves the problems that magnetic-control moment magnitude is limited, and a quantitative relation between selection of a weighting matrix and a performance index of an actual system is difficult to build in a traditional optimum control design method. The magnetic-control bias momentum satellite attitude control method based on the periodic Lyapunov equation comprises the steps that (1) a linear kinetic model of the magnetic-control bias momentum satellite attitude control system is built, (2) a symmetrical positive definite solution W(t) of the periodic Lyapunov equation is obtained, (3) a symmetrical positive definite solution P(t) of the periodic Riccati differential equation is obtained, (4) a state feedback controller is obtained, and (5) the control effect and the magnitude of control moment are tested. The magnetic-control bias momentum satellite attitude control method based on periodic Lyapunov equation is applied to the field of magnetic-control bias momentum satellite attitude control.

The invention relates to a polarization azimuth angle determination method based on a six-channel photoelectric sensor, which comprises the steps of acquiring polarization light intensity measurement information of each channel, realizing logarithm processing of the measurement information, judging with a logarithm processing result to obtain a polarization detection direction (a nearest polarization detection direction) with a minimum included angle with a polarization direction, obtaining a polarization azimuth angle distribution interval based on the nearest polarization detection direction, selecting a polarization azimuth angle calculation formula according to the polarization azimuth angle distribution interval, and realizing polarization azimuth angle calculation of the whole definition interval. The method has the advantages of high precision, good stability and the like, and can be used for determining a polarization azimuth angle of a polarization navigation system based on photoelectric measurement.

The invention discloses a robust digital audio watermark embedding and detection method based on polar harmonic transform. Advantages of great frequency domain localization features, multi-scale, redundancy and translation invariance, the features of non-stationary of greatly describing signals and maintaining the shape of the signals and the same length of audio frequency of each sub-band after decomposition with that of the original audio frequency of nonsubsampled wavelet transform are utilized; then great numerical stability of polar harmonic transform is also utilized, and watermarks are embedded in stable torque values to resist the normal signal attack; and then the synchronization code technology is combined. The experimental results indicate that normal signal processing can be resisted and the desynchronization attack can also be effectively resisted so that the method has great imperceptibility and robustness. Besides, the method also has advantages of being simple in design and easy to realize.

The invention relates to a device for MR imaging of a body (7) placed in an examination volume, the device (1) comprising means (2) for establishing a substantially homogeneous main magnetic field in the examination volume, means (3, 4, 5) for generating switched magnetic field gradients superimposed upon the main magnetic field, means (6) for radiating RF pulses towards the body (7), control means (12) for controlling the generation of the magnetic field gradients and the RF pulses, means (10) for receiving and sampling MR signals, and reconstruction means (14) for forming MR images from the signal samples. According to the invention, the device is arranged to a) generate a sequence of MR echo signals by subjecting at least a portion of the body (7) to a single RF pulse and a plurality of switched magnetic field gradients, the switched magnetic field gradients being controlled to produce at least two subsequences of MR echo signals, wherein each sub-sequence traverses a different trajectory in k-space with subsampling in the phase encoding direction (ky); b) acquire and sample the MR echo signals; c) reconstruct an MR image from the signal samples and from phase / amplitude correction maps associated with the sub-sequences of MR echo signals.

The invention discloses an implicit-projection-based method for simulating the stability of an active power distribution system. According to an active power distribution system stability simulation model with the rigidity characteristics, based on system simulation parameters and load flow calculation results, the implicit-projection-based method includes the steps that firstly, a plurality of steps of small-step-length integral calculation are carried out through an internal integrator, wherein the step length is h, and any explicit integral algorithm with the accuracy higher than the second order can be adopted; secondly, a step of large-step-length integral calculation is carried out with the step length Mh through an external integrator based on an implicit prediction-correction method according to the calculation result of the internal integrator. By means of the implicit-projection-based method, simulating calculation of system faults can be achieved, the implicit-projection-based method is a second-order accuracy algorithm and has the good numerical stability, a numerical stability domain of the implicit-projection-based method is hardly changed along with changes of the multiple of the step length of the external integrator, the performance of the algorithm is better than that of the explicit projection integral algorithm and that of a traditional implicit trapezoidal method, the implicit-projection-based method is suitable for rapidly achieving the aim of simulating the stability of the active power distribution system with the multi-time scale characteristics, and a foundation is laid for efficiently and reliably developing an active power distribution system simulation program.

The invention discloses a topologic partition based multi-section joint parameter estimation method. A multi-section joint parameter estimation algorithm is utilized for parameter estimation, so that the estimation measurement redundancy of power grid parameters is increased, the influence of error measurement on the power grid parameters is reduced, and the parameter estimation precision is improved. According to the method, in view of the problem of high calculated amount of the multi-section joint parameter estimation algorithm, a power grid is first partitioned according to a topologic connection relation, and a partition based parameter estimation model is established, so that the parameter estimation calculation scale is reduced. According to the method, maintenance parameters of a dispatching system is estimated and calculated, and theoretical estimation values of error parameters in the system are pointed out, so that the operation and maintenance workload is greatly reduced and the management level of the power grid parameters is improved.

The invention provides a calculation method for predicting the ship resistance based on CFD, and the method comprises the steps: S1, employing a two-phase incompressible RANS as a control equation, which comprises a continuity equation and a momentum equation; S2, processing a free surface through employing a single-phase level set method; S3, enabling a computational domain to be discretized into a series of small units through employing a finite volume method, calculating flow field information, and storing the flow field information at the gravity center of a grid unit; S4, obtaining values of unit surfaces according to the interpolation of the gravity center of the units; S5, solving the sum of the values of the unit surfaces, and obtaining the volume integral of a unit body; S6, carrying out the iterative solving of a pressure speed coupling equation, obtained after discretization, through employing a PISO implicit separation algorithm, wherein the calculation of each time step comprises momentum estimation, pressure solving and speed correction; and finally obtaining a convergent numerical solution. The method employs CFD to calculate and obtain a total resistance coefficient of a ship at a certain operating speed, and calculates and obtains the total resistance of the ship through a simple formula. The method is high in efficiency, is accurate, and is very strong in engineering practicality.

An electromechanical transient simulation modeling method of a direct-drive wind generating set is provided. A model consists of eight modules which are relatively independent in order to facilitate modular programming. The feedback quantity of each module uses a value at a last moment so that respective modules can be programmed according to sequential structure. In a simulation timing sequence process, two current converter modules are subjected to the dq axis fully decoupled assumption so that the d axis and q axis can be independently modeled. In addition, in order to correctly reflect the fault characteristics of a wind driven generator, a low voltage ride through (LVRT) control strategy is used in the corresponding module. In the simulation timing sequence process, a simulation technique combining large and small steps is used so that the rapid dynamic inside the wind driven generator can be accurately reflected. The method solves the problem that an electromechanical transient model of the wind driven generator cannot completely and accurately reflect the transient process of the wind driven generator.

The invention relates to a quick correction decoupling power system state estimating method considering zero injection constraint, belonging to the technical fields of power system scheduling automation and power system simulation. The quick correction decoupling power system state estimating method disclosed by the invention comprises the following steps of: establishing a least square state estimation model, carrying out iteration solution on the state estimation model according to regular quick decoupling estimation, correcting a node voltage amplitude and a phase angle of a nonzero injection node according to a correction quantity of the voltage amplitude and the phase angle figured out by a quick decoupling method in each iteration, and obtaining the node voltage amplitude and the phase angle of the zero injection node according to the relation between a zero injection node state variable and a nonzero injection node state variable determined according to a zero injection equality constraint, but not according to the calculation result of the quick decoupling estimation. According to the quick correction decoupling power system state estimating method considering zero injection constraint, disclosed by the invention, the whole calculation process is very similar to a traditional state estimation calculation procedure, is very convenient to realize; simultaneously, injection power of the zero injection node can be ensured to strictly be zero, and a state estimation result strictly meets a power flow equation.

The invention provides a background grid adaptive segmenting method in a DC resistivity no-unit method. The method comprises the following steps of determining distribution condition of medium, abnormal member, landform, electrode and the like in a two-dimensional ground electric model, establishing a DC resistivity no-unit method calculating domain, and utilizing an irregularly distributed node discrete ground electric model; covering the calculating domain by means of a small number of rough and simple initial quadrangular grids, setting a control value which guides adaptive segmentation, and performing adaptive segmentation by the background grid according to the control value and a node distribution condition; arranging ng Gaussian integration points xg in each background grid, and obtaining a no-unit method equation set of the region; solving the equation set for obtaining a node electric field value, and calculating the vision resistivity parameter of a viewing point. The methodcan be based on any node distribution discrete model. High adaptability for any complicated ground electric model is realized. The background grid adaptive segmenting method improves value stability and computing efficiency in routine DC resistivity no-unit method forward calculation.

The invention relates to a navigation data processing method and system. The method comprises the following steps: S1, an input intermediate frequency signal and a carrier signal are subjected to carrier stripping by a mixer; S2, a lead correlation value, an instant correlation value and a lag correlation value are output after a navigation signal and a local pseudo code pass through a correlator; S3, lead and lag navigation data signals enter a code loop phase discriminator, are filtered by a code loop filter and then enter a local pseudo-code generator to make thus generated pseudo code same as that of the intermediate frequency signal in term of phase; S4, an instant road navigation data signal enters a carrier loop phase discriminator, enters a carrier digital control oscillator via the filter, wherein the phase of the carrier generated by the instant road navigation data signal is the same as that of the carrier generated by the intermediate frequency signal. The system comprises a signal input module, a correlator processing module, a code loop processing module and a carrier processing module. The method tracks the motion state of the carrier, improves the tracking accuracy, and obtains an accurate observation value.

The invention relates to a self-contained navigation method for measurement of an earth ultraviolet sensor, which comprises the following steps of: initializing: utilizing satellite injection information to supply a state initial value and a covariance initial value outlier of a satellite at a starting moment, accumulating geocentric vector information and earth apparent radius information obtained by the ultraviolet sensor for a specified period of time, and then utilizing an outlier eliminating algorithm to eliminate the outlier in the information; batch processing: performing a least square method on the geocentric vector information and the earth apparent radius information after the outlier is eliminated, and calculating a state estimation Xk and a covariance estimation Pk of the satellite at an ending moment of observation; unscented transformation: utilizing the unscented transformation to realize the time updating of the state and the covariance, obtaining a state forecast X(k+1) and covariance forecast P(k+1) of the satellite at the next ending moment of observation; and recursion: continuously accumulating the geocentric vector information and the earth apparent radius information for a period of time, and repeating the steps and performing continuous recursion and calculation, thereby continuously obtaining the estimation of the state of the satellite. According to the method, the precision and the stability of a navigation system are increased.