Method and apparatus for calculating ionospheric electron density and electron content

Abstract

The application discloses a method and device for calculating ionospheric electron density and electron content, wherein the method for calculating ionospheric electron density comprises the following steps: obtaining an electron content observation value of an ionospheric piercing point and an ionospheric electron density background value of a three-dimensional regular network; performing data assimilation on the electron content observation value and the ionospheric electron density background value to obtain an expression of an ionospheric electron density analysis value; constructing an observation error analysis function according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value; taking minimization of the observation error analysis function as an objective function to obtain a target position variance factor; and calculating a corrected ionospheric electron density analysis value according to the target position variance factor. The application can calibrate the calculation result of the ionospheric electron density, can more accurately describe the distribution of electrons in space, and thus improves the prediction accuracy of the model.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of GNSS atmospheric monitoring, and in particular to a method and device for calculating ionospheric electron density and electron content. BACKGROUND

[0002] The ionosphere is an important part of the space environment, and monitoring and researching various phenomena in the ionosphere can reveal the spatiotemporal variation and physical mechanism of the ionosphere. The ionospheric electron density (IED) distribution is particularly important, and plays an important role in radio and satellite communication and satellite positioning.

[0003] In the calculation of ionospheric electron density, it is important to have prior information of global empirical model of IED, such as IRI and NeQuick global empirical model. Global empirical models are usually based on simplified assumptions, which may not be accurate in describing how electrons are distributed in the actual system. The prediction accuracy of the model is not high, resulting in inaccurate calculation of ionospheric electron density. SUMMARY

[0004] The present application provides a method and device for calculating ionospheric electron density and electron content to solve the technical problem of inaccurate calculation of ionospheric electron density and electron content caused by low prediction accuracy of global empirical model.

[0005] To solve the above technical problem, the present application provides a method for calculating ionospheric electron density, comprising:

[0006] Obtaining an electron content observation value of an ionospheric piercing point and an ionospheric electron density background value of a three-dimensional regular network; wherein the three-dimensional regular network is provided by a global empirical model;

[0007] According to the electron content observation value and the ionospheric electron density background value, data assimilation is performed to obtain an expression of ionospheric electron density analysis value; wherein the expression is an expression of ionospheric electron density with respect to position variance factor;

[0008] According to the expression of ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value, an observation error analysis function is constructed;

[0009] Taking the minimization of the observation error analysis function as the objective function, the target position variance factor is obtained by solving;

[0010] According to the target position variance factor, the corrected ionospheric electron density analysis value is calculated by the expression of ionospheric electron density analysis value.

[0011] As a preferred scheme, before obtaining the electron content observation value of the ionospheric piercing point, it further comprises:

[0012] acquiring carrier phase observations of the ionospheric pierce point by a dual-frequency GNSS receiver;

[0013] calculating electron content observations of the ionospheric pierce point according to the carrier phase observations;

[0014] wherein the electron content observation calculation formula is:

[0015] ;

[0016] wherein, represents the electron content observation; represents the carrier phase observation; and are signal frequencies used by the dual-frequency receiver; is a pseudo-range hardware delay; is a satellite dual-frequency code bias; is a dual-frequency code bias of the dual-frequency receiver.

[0017] As a preferred solution, the data assimilation according to the electron content observations and the ionospheric electron density background value comprises:

[0018] assimilating the electron content observations and the ionospheric electron density background value with the longitude and latitude position of the ionospheric pierce point as a reference position to obtain an expression of ionospheric electron density analysis value as follows:

[0019] ;

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] ;

[0025] wherein, represents the longitude of a grid point with an index of in the longitude direction and an index of in the latitude direction in a three-dimensional regular network; represents the latitude of a grid point with an index of in the longitude direction and an index of in the latitude direction in a three-dimensional regular network; represents the height of a grid point with an index of The height of the grid points; Indicates position Analysis of electron density in the ionosphere; Indicates position Background value of ionospheric electron density; This indicates the total number of grid cells along the longitude direction in a 3D grid. This represents the total number of grid cells in all dimensional directions of a 3D mesh. This represents the total number of grid cells in the height direction of the 3D mesh. This represents the assimilation weight matrix; Longitude indicating the reference position; The dimension representing the reference position; Represents the observation submatrix; Represents the coefficient matrix of the observed values; Represents the covariance matrix of the observations; Represents the observation weight matrix; Indicates random error; Indicates the location variance factor; It is a unit array.

[0026] As a preferred embodiment, the expression for the observation error analysis function is:

[0027] ;

[0028] In the formula, This represents the observation error analysis function.

[0029] As a preferred embodiment, the step of minimizing the observation error analysis function as the objective function to obtain the target position variance factor includes:

[0030] Under the condition that the location variance factor is greater than 0, the target location variance factor is obtained by minimizing the observation error analysis function.

[0031] The formula for solving the target location variance factor is as follows:

[0032] .

[0033] As a preferred embodiment, the three-dimensional rule network has a longitude resolution of 0.5°, a dimensional resolution of 0.5°, a height resolution of 50 kilometers, and a height range of 100 kilometers to 2000 kilometers above sea level.

[0034] This invention also provides a method for calculating electron content, comprising:

[0035] obtaining corrected ionospheric electron density analysis values of grid points corresponding to a grid where the ionospheric piercing point is located and all height layers overlapping with the grid where the ionospheric piercing point is located in a horizontal plane; wherein the grid is a grid in a three-dimensional regular network provided by a global empirical model; the grid point is a grid point in the three-dimensional regular network provided by the global empirical model; and the corrected ionospheric electron density analysis values are calculated according to the electron content calculation method as described in the above embodiment of the application;

[0036] calculating the electron content of the ionospheric piercing point according to all the corrected ionospheric electron density analysis values.

[0037] As a preferred solution, the step of calculating the electron content of the ionospheric piercing point according to all the corrected ionospheric electron density analysis values comprises:

[0038] calculating a weighted average value of the corrected ionospheric electron density analysis value corresponding to each height layer;

[0039] summing up the weighted average values corresponding to all height layers to obtain the electron content of the ionospheric piercing point.

[0040] wherein the calculation formula of the electron content of the ionospheric piercing point is:

[0041] ;

[0042] wherein, represents the electron content of the ionospheric piercing point; represents the longitude of the grid point in the three-dimensional regular network with the longitude index of and the dimension index of ; represents the dimension of the grid point in the three-dimensional regular network with the longitude index of and the dimension index of ; represents the height of the grid point in the three-dimensional regular network with the height index of ; represents the ionospheric electron density analysis value at the position ; represents the weight value of the th corrected ionospheric electron density analysis value corresponding to the th height layer; represents the total number of height layers; represents the total number of corrected ionospheric electron density analysis values corresponding to each height layer.

[0043] On the basis of the above-mentioned embodiments, another embodiment of the present application provides an ionospheric electron density calculation device, comprising: a first data acquisition module, a data assimilation module and a correction module.

[0044] The first data acquisition module is configured to acquire an electron content observation value of an ionospheric pierce point and an ionospheric electron density background value of a three-dimensional regular network; wherein the three-dimensional regular network is provided by a global empirical model.

[0045] The data assimilation module is configured to perform data assimilation according to the electron content observation value and the ionospheric electron density background value, so as to obtain an expression of an ionospheric electron density analysis value; wherein the expression is an expression of the ionospheric electron density about a position variance factor.

[0046] The correction module is configured to construct an observation error analysis function according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value; to take minimization of the observation error analysis function as an objective function, so as to obtain a target position variance factor; and to calculate a corrected ionospheric electron density analysis value through the expression of the ionospheric electron density analysis value according to the target position variance factor.

[0047] On the basis of the above-mentioned embodiments, another embodiment of the present application provides an electron content calculation device, wherein the electron content calculation device comprises: a second data acquisition module and an electron content calculation module.

[0048] The second data acquisition module is configured to acquire a grid where an ionospheric pierce point to be solved is located and a corrected ionospheric electron density analysis value of a grid point corresponding to a grid on all height layers overlapping with the grid where the ionospheric pierce point is located in a horizontal plane; wherein the grid is a grid in a three-dimensional regular network provided by a global empirical model; the grid point is a grid point in the three-dimensional regular network provided by the global empirical model; and the corrected ionospheric electron density analysis value is calculated according to the electron content calculation method as described in the above-mentioned embodiments of the present application.

[0049] The electron content calculation module is configured to calculate the electron content of the ionospheric pierce point according to all the corrected ionospheric electron density analysis values.

[0050] On the basis of the above-mentioned embodiments, still another embodiment of the present application provides a terminal device, comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the electron content calculation method as described in the above-mentioned embodiments of the present application when executing the computer program.

[0051] On the basis of the above-mentioned embodiments, a storage medium is further provided in another embodiment of the present application, which comprises a stored computer program, wherein the computer program controls a device where the storage medium is located to execute the electronic content calculation method in the above-mentioned embodiments of the present application when the computer program is running.

[0052] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0053] The present application obtains the electron content observation value of the ionospheric piercing point and the ionospheric electron density background value of the three-dimensional regular network; performs data assimilation on the electron content observation value and the ionospheric electron density background value to obtain an expression of the ionospheric electron density analysis value; constructs an observation error analysis function according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value; takes the minimization of the observation error analysis function as an objective function to obtain a target position variance factor; and calibrates the ionospheric electron density through the expression of the ionospheric electron density analysis value according to the target position variance factor to obtain a calculated corrected ionospheric electron density analysis value. The present application calibrates the calculation result of the ionospheric electron density, which can more accurately describe the distribution of electrons in space, thereby improving the prediction accuracy of the model. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a flowchart of an ionospheric electron density calculation method provided by an embodiment of the present application;

[0055] Figure 2 is a flowchart of an electronic content calculation method provided by an embodiment of the present application;

[0056] Figure 3 is a structural diagram of an ionospheric electron density calculation device provided by an embodiment of the present application;

[0057] Figure 4 is a structural diagram of an electronic content calculation device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0059] Embodiment One

[0060] Please refer to Figure 1A flowchart of an ionospheric electron density calculation method provided by an embodiment of the present application includes:

[0061] In step S101, an electron content observation value of an ionospheric piercing point is obtained, and ionospheric electron density background values of a three-dimensional regular network are obtained, wherein the three-dimensional regular network is provided by a global empirical model.

[0062] In step S101, an ionospheric piercing point is selected, and an electron content observation value of the ionospheric piercing point is obtained. The three-dimensional regular network provided by the global empirical model contains ionospheric electron density background values of each grid point, and ionospheric electron density background values of all grid points of the three-dimensional regular network are obtained.

[0063] In a preferred embodiment, before the electron content observation value of the ionospheric piercing point is obtained, the following steps are further included:

[0064] A carrier phase observation value of the ionospheric piercing point is obtained by a dual-frequency GNSS receiver;

[0065] An electron content observation value of the ionospheric piercing point is calculated according to the carrier phase observation value;

[0066] The electron content observation value calculation formula is as follows:

[0067]

[0068] In the formula, N is the electron content observation value, φ is the carrier phase observation value, f1 and f2 are signal frequencies used by the dual-frequency receiver, c is the speed of light, T is the pseudo-range hardware delay, B1 and B2 are dual-frequency code biases of the satellite, and B1' and B2' are dual-frequency code biases of the dual-frequency receiver. The electron content observation value is represented by N; The carrier phase observation value is represented by φ; f1 and f2 are signal frequencies used by the dual-frequency receiver; T is the pseudo-range hardware delay; B1 and B2 are dual-frequency code biases of the satellite; B1' and B2' are dual-frequency code biases of the dual-frequency receiver. In the embodiment, the carrier phase observation value of the ionospheric piercing point is obtained by the dual-frequency GNSS receiver, and the electron content observation value at the ionospheric piercing point can be calculated.

[0069] In a preferred embodiment, the longitude resolution of the three-dimensional regular network is 0.5°, the latitude resolution is 0.5°, the height resolution is 50 kilometers, and the height range is from 100 kilometers above sea level to 2000 kilometers above sea level.

[0070]

[0071] ​​In the embodiment, the three-dimensional regular network obtained from the global empirical model is an equidistant regular spherical network, which is a three-dimensional regular network of ionospheric electron density. The longitude and latitude rates of the network are 0.5°×0.5°, and the network is composed of 39 height layers from an altitude of 100 km to an altitude of 2000 km with a fixed step of 50 km.

[0072] S102, according to the electron content observation value and the ionospheric electron density background value, data assimilation is carried out to obtain the expression of the ionospheric electron density analysis value; wherein the expression is the expression of the ionospheric electron density about the position variance factor.

[0073] It should be noted that the modeling time of the global empirical model is divided into 10-minute subintervals. In the middle of each subinterval, the three-dimensional regular network of ionospheric electron density is received from the global empirical model online service. In each one-hour interval, there are 6 subintervals. The electron content observation value of each subinterval is assimilated into the background ionospheric electron density grid in the middle of the subinterval, i.e. the three-dimensional regular network.

[0074] In a preferred embodiment, the data assimilation according to the electron content observation value and the ionospheric electron density background value comprises:

[0075] The electron content observation value and the ionospheric electron density background value are assimilated with the longitude and latitude positions of the ionospheric piercing point as the reference position to obtain the following expression of the ionospheric electron density analysis value:

[0076] ;

[0077] ;

[0078] ;

[0079] ;

[0080] ;

[0081] ;

[0082] In the formula, represents the longitude of the grid point in the three-dimensional regular network with an index of in the longitude direction and an index of in the latitude direction; represents the latitude of the grid point in the three-dimensional regular network with an index of in the longitude direction and an index of in the latitude direction; represents the height of the grid point in the three-dimensional regular network with an index of height of the grid point; representing position ionospheric electron density analysis value at the position representing position ionospheric electron density background value at the position representing all grid numbers in longitude direction in the three-dimensional grid; representing all grid numbers in latitude direction in the three-dimensional grid; representing all grid numbers in height direction in the three-dimensional grid; representing assimilation weight matrix; representing longitude of the reference position; representing latitude of the reference position; representing observation sub-matrix; representing observation coefficient matrix; representing observation covariance matrix; representing observation weight matrix; representing random error; representing position variance factor; is an identity matrix.

[0083] It should be noted that the optimal interpolation method is used in the embodiment to map the ionospheric electron density background value on the equidistant regular spherical grid to the electron content observation value at the ionospheric piercing point, and the data assimilation is performed for calibration. The random error is assigned according to experience.

[0084] In the embodiment, the observation covariance matrix and the observation coefficient matrix need to be constructed when the data assimilation is performed. representing observation coefficient matrix. In each sub-interval, the observation covariance matrix can be obtained by inversion of the observation weight matrix. When the data assimilation is performed, the relationship between the background and the observation variance needs to be established, which requires the position variance factor. Finally, the expression of the ionospheric electron density analysis value is constructed through the data assimilation, and the expression is about the position variance factor.

[0085] S103, constructing an observation error analysis function according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value.

[0086] In step S103, in order to solve the optimization problem of finding the optimal position variance factor, the observation error analysis function needs to be constructed according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value.

[0087] In a preferred embodiment, the expression of the observation error analysis function is:

[0088] ;

[0089] wherein, represents an observation error analysis function.

[0090] S104, solving a target position variance factor with the observation error analysis function minimized as an objective function.

[0091] In step S104, the position variance factor that makes the observation error analysis function minimum is the target position variance factor to be found.

[0092] In a preferred embodiment, the solving of the target position variance factor with the observation error analysis function minimized as an objective function comprises:

[0093] Solving the target position variance factor with the observation error analysis function minimized as an objective function under the condition that the position variance factor is greater than 0;

[0094] Wherein, the solving formula of the target position variance factor is:

[0095] .

[0096] In this embodiment, the point-in-method is used to solve the optimization problem, and the basis of this method is to add the constraint as a function to the objective function, and use the quasi-Newton method to minimize the newly obtained objective function.

[0097] S105, calculating the corrected ionospheric electron density analysis value according to the expression of the ionospheric electron density analysis value and the target position variance factor.

[0098] In this embodiment, the target position variance is substituted into the ionospheric electron density expression to calculate the corrected ionospheric electron density analysis value.

[0099] Embodiment two

[0100] Please refer to Figure 2 A flowchart of an electronic content calculation method provided by an embodiment of the present application, the electronic content calculation method comprising:

[0101] S201, obtaining the corrected ionospheric electron density analysis value of the grid point corresponding to the grid where the ionospheric piercing point is located and all height layers overlapping the grid in the horizontal plane; wherein the grid is a grid in the three-dimensional regular network provided by the global empirical model; the grid point is a grid point in the three-dimensional regular network provided by the global empirical model; and the corrected ionospheric electron density analysis value is calculated according to the electronic content calculation method as described in the above embodiment.

[0102] It should be noted that when calculating the electron content of the ionospheric piercing point, the electron content at each height layer is affected by the ionospheric electron density of the four grid points of the grid where the ionospheric piercing point is located. Each observation value projected vertically to the ground direction of each ionospheric piercing point may be affected by the prismatic electron density.

[0103] In step S201, the grid where the ionospheric piercing point to be calculated vertically to the ground direction of all height layers is determined, including the grid where the ionospheric piercing point itself is located and the grid of other height layers overlapping with it in the horizontal plane. Then the corrected ionospheric electron density analysis values of the grid points corresponding to the grid are obtained. The grid points corresponding to the grid are the four vertices of the grid.

[0104] S202, according to all the corrected ionospheric electron density analysis values, the electron content of the ionospheric piercing point is calculated.

[0105] In a preferred embodiment, the electron content of the ionospheric piercing point is calculated according to all the corrected ionospheric electron density analysis values, including:

[0106] For each height layer, the weighted average value of the corrected ionospheric electron density analysis value corresponding to the height layer is calculated;

[0107] The weighted average values corresponding to all height layers are summed to obtain the electron content of the ionospheric piercing point;

[0108] The calculation formula of the electron content of the ionospheric piercing point is:

[0109] ;

[0110] In the formula, represents the electron content of the ionospheric piercing point; represents the longitude of the grid point in the three-dimensional regular network with longitude index and dimension index ; represents the dimension of the grid point in the three-dimensional regular network with longitude index and dimension index ; represents the height of the grid point in the three-dimensional regular network with height index ; represents the ionospheric electron density analysis value at position ; represents the weight value of the th corrected ionospheric electron density analysis value corresponding to the th height layer; denotes the total number of height layers; denotes the total number of the corrected ionospheric electron density analysis values corresponding to each height layer.

[0111] In the embodiment, the layer electron density of each height layer is first calculated, that is, the weighted average value of the corrected ionospheric electron density analysis value corresponding to each height layer is calculated; then the layer electron densities of all height layers are summed up, and the obtained is the electron content of the ionospheric piercing point to be solved.

[0112] Embodiment three

[0113] Please refer to Figure 3 A structural schematic diagram of an ionospheric electron density calculation device provided by an embodiment of the present application, comprising: a first data acquisition module, a data assimilation module and a correction module;

[0114] The first data acquisition module is configured to acquire the electron content observation value of the ionospheric piercing point and the ionospheric electron density background value of a three-dimensional regular network; wherein the three-dimensional regular network is provided by a global empirical model.

[0115] The data assimilation module is configured to perform data assimilation according to the electron content observation value and the ionospheric electron density background value, and obtain an expression of the ionospheric electron density analysis value; wherein the expression is an expression of the ionospheric electron density about a position variance factor.

[0116] The correction module is configured to construct an observation error analysis function according to the expression of the ionospheric electron density analysis value, the electron content observation value and the ionospheric electron density background value; take the minimization of the observation error analysis function as an objective function, and solve to obtain a target position variance factor; and calculate the corrected ionospheric electron density analysis value through the expression of the ionospheric electron density analysis value according to the target position variance factor.

[0117] Embodiment four

[0118] Please refer to Figure 4 A structural schematic diagram of an electron content calculation device provided by an embodiment of the present application, comprising: a second data acquisition module and an electron content calculation module.

[0119] The second data acquisition module is configured to acquire corrected ionospheric electron density analysis values of grid points corresponding to a grid where an ionospheric piercing point to be solved is located and all height layers overlapping with the grid where the ionospheric piercing point is located in a horizontal plane; wherein the grid is a grid in a three-dimensional regular network provided by a global empirical model; the grid point is a grid point in the three-dimensional regular network provided by the global empirical model; and the corrected ionospheric electron density analysis values are calculated according to the electronic content calculation method as described in the above embodiment.

[0120] The electronic content calculation module is configured to calculate the electronic content of the ionospheric piercing point according to all the corrected ionospheric electron density analysis values.

[0121] It should be noted that the apparatus embodiments described above are merely illustrative, and the units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e., they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment according to actual needs. In addition, the connection relationship between the modules in the apparatus embodiment provided by the present application indicates that there is a communication connection between them, which can be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement it without creative labor.

[0122] Those skilled in the art can clearly understand that, for the convenience and brevity, the specific working process of the apparatus described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0123] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only for specific embodiments of the present application and is not intended to limit the protection scope of the present application. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0124] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0125] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

Claims

1. A method for calculating ionospheric electron density, characterized in that, include: The observed electron content at the ionospheric puncture point and the background electron density of the ionosphere from a three-dimensional regular network are obtained; wherein, the three-dimensional regular network is provided by a global empirical model. Based on the observed electron content and the background ionospheric electron density, data assimilation is performed to obtain an expression for the ionospheric electron density analysis value; wherein, the expression is an expression for the ionospheric electron density with respect to the position variance factor; An observation error analysis function is constructed based on the expression of the ionospheric electron density analysis value, the observed electron content value, and the background value of the ionospheric electron density; The target position variance factor is obtained by minimizing the observation error analysis function. Based on the target location variance factor, the corrected ionospheric electron density analysis value is calculated using the expression for the ionospheric electron density analysis value. The data assimilation based on the observed electron content and the background ionospheric electron density includes: Using the latitude and longitude of the ionospheric puncture point as a reference position, the observed electron content and the background ionospheric electron density are assimilated to obtain the following expression for the ionospheric electron density analysis value: ； ； ； ； ； ； In the formula, The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The longitude of the grid points; The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The dimensions of the grid points; The exponent in the height direction of a 3D regular network is... The height of the grid points; Indicates position Analysis of electron density in the ionosphere; Indicates position Background value of ionospheric electron density; This indicates the total number of grid cells along the longitude direction in a 3D grid. This represents the total number of grid cells in all dimensional directions of a 3D mesh. This represents the total number of grid cells in the height direction of the 3D mesh. This represents the assimilation weight matrix; Longitude indicating the reference position; The dimension representing the reference position; Represents the observation submatrix; Represents the coefficient matrix of the observed values; Represents the covariance matrix of the observations; Represents the observation weight matrix; Indicates random error; Indicates the location variance factor; For unit array; The expression for the observation error analysis function is: ； In the formula, Represents the observation error analysis function; The objective function for minimizing the observation error analysis function is to obtain the target position variance factor, which includes: Under the condition that the location variance factor is greater than 0, the target location variance factor is obtained by minimizing the observation error analysis function. The formula for solving the target location variance factor is as follows: 。 2. The method for calculating ionospheric electron density as described in claim 1, characterized in that, Before obtaining the electron content observation values ​​at the ionospheric puncture site, the following steps are also included: The carrier phase observation value of the ionospheric puncture point was obtained by using a dual-frequency GNSS receiver; Calculate the observed electron content at the ionospheric puncture point based on the carrier phase observations. The formula for calculating the observed electron content is as follows: ； In the formula, This represents the observed value of electron content; Represents the carrier phase observation value; and The signal frequency used by the dual-frequency receiver; For pseudorange hardware delay; This refers to the dual-frequency code offset of the satellite; This represents the dual-frequency code deviation of a dual-frequency receiver.

3. The method for calculating ionospheric electron density as described in claim 1, characterized in that, The three-dimensional rule network has a longitude resolution of 0.5°, a dimensional resolution of 0.5°, an altitude resolution of 50 kilometers, and an altitude range from 100 kilometers to 2000 kilometers above sea level.

4. A method for calculating electron content, characterized in that, include: Obtain the corrected ionospheric electron density analysis values ​​of grid points near the ionospheric puncture point to be solved; wherein, the grid points near the ionospheric puncture point refer to the grid points corresponding to the grid where the ionospheric puncture point is located and the grid points corresponding to all grid points on all height layers overlapping the grid where the ionospheric puncture point is located on the horizontal plane; the grid is a grid in the three-dimensional regular network provided by the global empirical model; the grid points are grid points in the three-dimensional regular network provided by the global empirical model; the corrected ionospheric electron density analysis values ​​are calculated according to any one of the claims 1 to 3; The electron content at the ionospheric puncture site is calculated based on all the corrected ionospheric electron density analysis values.

5. The method for calculating electron content as described in claim 4, characterized in that, The step of calculating the electron content at the ionospheric puncture point based on all the corrected ionospheric electron density analysis values ​​includes: For each altitude layer, calculate the weighted average of the corrected ionospheric electron density analysis values ​​corresponding to that altitude layer; The electron content at the ionospheric puncture point is obtained by summing the weighted average values ​​corresponding to all height layers. The formula for calculating the electron content at the ionospheric puncture point is as follows: ； In the formula, Indicates the electron content at the ionospheric puncture site; The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The longitude of the grid points; The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The dimensions of the grid points; The exponent in the height direction of a 3D regular network is... The height of the grid points; Indicates position Analysis of electron density in the ionosphere; Indicates the first The height level corresponds to the first The weight values ​​of the corrected ionospheric electron density analysis values; Indicates the total number of height levels; This represents the total number of corrected ionospheric electron density analysis values ​​corresponding to each altitude layer.

6. An ionospheric electron density calculation device, characterized in that, include: The module consists of a first data acquisition module, a data assimilation module, and a correction module. The first data acquisition module is used to acquire the observed electron content at the ionospheric puncture point and the background electron density of the ionospheric region from the three-dimensional regular network; wherein the three-dimensional regular network is provided by a global empirical model. The data assimilation module is used to assimilate data based on the observed electron content and the background ionospheric electron density to obtain an expression for the ionospheric electron density analysis value; wherein, the expression is an expression for the ionospheric electron density with respect to the position variance factor; The correction module is used to construct an observation error analysis function based on the expression of the ionospheric electron density analysis value, the observed electron content value, and the background value of the ionospheric electron density; to obtain the target position variance factor by minimizing the observation error analysis function as the objective function; and to calculate the corrected ionospheric electron density analysis value based on the target position variance factor and the expression of the ionospheric electron density analysis value. The data assimilation based on the observed electron content and the background ionospheric electron density includes: Using the latitude and longitude of the ionospheric puncture point as a reference position, the observed electron content and the background ionospheric electron density are assimilated to obtain the following expression for the ionospheric electron density analysis value: ； ； ； ； ； ； In the formula, The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The longitude of the grid points; The exponent in the longitude direction of a three-dimensional regular network is... The exponent in the dimensional direction is The dimensions of the grid points; The exponent in the height direction of a 3D regular network is... The height of the grid points; Indicates position Analysis of electron density in the ionosphere; Indicates position Background value of ionospheric electron density; This indicates the total number of grid cells along the longitude direction in a 3D grid. This represents the total number of grid cells in all dimensional directions of a 3D mesh. This represents the total number of grid cells in the height direction of the 3D mesh. This represents the assimilation weight matrix; Longitude indicating the reference position; The dimension representing the reference position; Represents the observation submatrix; Represents the coefficient matrix of the observed values; Represents the covariance matrix of the observations; Represents the observation weight matrix; Indicates random error; Indicates the location variance factor; For unit array; The expression for the observation error analysis function is: ； In the formula, Represents the observation error analysis function; The objective function for minimizing the observation error analysis function is to obtain the target position variance factor, which includes: Under the condition that the location variance factor is greater than 0, the target location variance factor is obtained by minimizing the observation error analysis function. The formula for solving the target location variance factor is as follows: 。 7. An electron content calculation device, characterized in that, include: The second data acquisition module and the electron content calculation module; The second data acquisition module is used to acquire the corrected ionospheric electron density analysis values ​​of the grid points corresponding to the grids at all height layers that overlap with the grid points at the ionospheric puncture point on the horizontal plane; wherein, the grid is a grid in a three-dimensional regular network provided by a global empirical model; the grid points are grid points in a three-dimensional regular network provided by the global empirical model; and the corrected ionospheric electron density analysis values ​​are calculated according to any one of claims 1 to 3. The electron content calculation module is used to calculate the electron content of the ionospheric puncture point based on all the corrected ionospheric electron density analysis values.

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