Ionosphere inversion precision evaluation method, device and equipment and storage medium

Abstract

The application discloses an ionosphere inversion precision evaluation method and device, equipment and a storage medium, and relates to the technical field of ionosphere detection. The method comprises the following steps: acquiring observation data of an ionosphere inversion area by using a space-borne synthetic aperture radar, and extracting ionosphere electron content in the observation data; inputting the observation data into a preset ionosphere electron content calculation model to obtain target ionosphere electron content of the ionosphere inversion area; and performing precision evaluation on the ionosphere electron content based on the target ionosphere electron content. The application can evaluate the precision of the ionosphere inversion by the space-borne synthetic aperture radar by using high-precision ionosphere results obtained by global navigation satellite system technology, so that the precision of the ionosphere inversion by the space-borne synthetic aperture radar can be more accurately evaluated.

Description

Technical Field

[0001] This application relates to the field of ionospheric detection technology, and in particular to a method, apparatus, equipment, and storage medium for evaluating the accuracy of ionospheric inversion. Background Technology

[0002] In recent years, ionospheric inversion based on SAR (Synthetic Aperture Radar) technology has brought new ideas to ionospheric detection. This technology extracts ionospheric information through methods such as electromagnetic wave Faraday rotation estimation and spectrum separation, yielding a more refined total electron content of the ionosphere. Evaluating the accuracy of SAR-derived ionospheric inversion is essential, as the evaluation results determine the accuracy of the inversion. Existing techniques for evaluating the accuracy of SAR-derived ionospheric inversion use SAR ionospheric inversion results to correct ionospheric errors in InSAR (Interferometric Synthetic Aperture Radar) interferometry, evaluating the effectiveness of SAR ionospheric inversion based on the improvement in measurement accuracy. However, this evaluation method is indirect and the accuracy of the results is not high.

[0003] Therefore, improving the accuracy of ionospheric inversion assessment is a problem that urgently needs to be solved.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this application is to provide a method, apparatus, device, and storage medium for evaluating the accuracy of ionospheric inversion, aiming to solve the technical problem of how to improve the accuracy of ionospheric inversion evaluation.

[0006] To achieve the above objectives, this application proposes a method for evaluating the accuracy of ionospheric inversion, the method comprising:

[0007] Observational data of the ionospheric inversion region were acquired using a spaceborne synthetic aperture radar, and the ionospheric electron content in the observational data was extracted.

[0008] The observation data is input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region.

[0009] The accuracy of the ionospheric electron content is evaluated based on the target ionospheric electron content.

[0010] In one embodiment, the observation data includes at least ground images;

[0011] The observed data is input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content, including:

[0012] Determine the latitude and longitude coordinates of the target pixels in the ground image;

[0013] The latitude and longitude coordinates are transformed to obtain the coordinates of the ionospheric puncture point, which is the intersection of the spaceborne synthetic aperture radar and the target pixel on the thin layer of the ionosphere.

[0014] The coordinates of the ionospheric puncture point are input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

[0015] In one embodiment, the step of transforming the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point includes:

[0016] Extract the discrete point coordinates of the synthetic aperture radar's orbit from the observation data;

[0017] The target trajectory is obtained by fitting the trajectory based on the coordinates of the discrete points.

[0018] Based on the latitude and longitude coordinates and the orbital coordinates at the corresponding time on the target orbit, the pixel satellite elevation angle and azimuth angle of the synthetic aperture radar are calculated;

[0019] The coordinates of the ionospheric puncture point are calculated based on the latitude and longitude coordinates, the altitude angle, and the azimuth angle.

[0020] In one embodiment, before performing trajectory fitting based on the discrete point coordinates to obtain the target trajectory, the method further includes:

[0021] Interpolation is performed on the discrete point coordinates to obtain the target discrete point coordinates, wherein the number of target discrete point coordinates is greater than the number of discrete point coordinates;

[0022] Accordingly, the step of fitting the trajectory based on the discrete point coordinates to obtain the target trajectory includes:

[0023] The target trajectory is obtained by fitting the trajectory based on the coordinates of the target discrete points.

[0024] In one embodiment, before the step of inputting the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content, the following steps are included:

[0025] Acquire observation data samples from the Global Navigation Satellite System;

[0026] Based on the observed data sample, the ionospheric electron content sample was calculated;

[0027] Based on the observed data sample and the ionospheric electron content sample, a preset ionospheric electron content calculation model is established.

[0028] In one embodiment, calculating the ionospheric electron content sample based on the observed data sample includes:

[0029] The observation data sample is smoothed to obtain the target observation data sample;

[0030] Based on the target observation data sample, the ionospheric electron content sample is calculated.

[0031] In one embodiment, the step of accurately assessing the ionospheric electron content based on the target ionospheric electron content includes:

[0032] The content difference of the ionosphere at each puncture point is determined based on the ionospheric electron content and the target ionospheric electron content.

[0033] Calculate the mean and / or root mean square error among the differences in content;

[0034] The accuracy of the ionospheric electron content is assessed based on the mean and / or the root mean square error.

[0035] Furthermore, to achieve the above objectives, this application also proposes an ionospheric inversion accuracy evaluation device, which includes:

[0036] The acquisition module is used to acquire observational data of the ionospheric inversion region through a spaceborne synthetic aperture radar and extract the ionospheric electron content from the observational data.

[0037] The calculation module is used to input the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region;

[0038] An evaluation module is used to perform an accuracy evaluation of the ionospheric electron content based on the target ionospheric electron content.

[0039] In addition, to achieve the above objectives, this application also proposes an ionospheric inversion accuracy assessment device, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the ionospheric inversion accuracy assessment method as described above.

[0040] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the ionospheric inversion accuracy evaluation method described above.

[0041] This application provides a method for evaluating the accuracy of ionospheric inversion. First, observational data of the ionospheric inversion region is acquired using a spaceborne synthetic aperture radar, and the ionospheric electron content is extracted from the observational data. The observational data is then input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region. Based on the target ionospheric electron content, the accuracy of the ionospheric electron content is evaluated.

[0042] In summary, this application transforms the pixel coordinates of the synthetic aperture radar into ionospheric thin-layer coordinates, and compares the ionospheric inversion results of the spaceborne synthetic aperture radar with the ionospheric results of the global satellite navigation system within the same coordinate framework. This enables a direct and effective assessment of the ionospheric inversion accuracy of the spaceborne synthetic aperture radar, and improves the accuracy of ionospheric inversion accuracy assessment compared with existing indirect assessment techniques. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating the first embodiment of the ionospheric inversion accuracy assessment method of this application;

[0046] Figure 2 This is a flowchart illustrating the second embodiment of the ionospheric inversion accuracy assessment method of this application;

[0047] Figure 3 This is a flowchart illustrating the third embodiment of the ionospheric inversion accuracy evaluation method of this application;

[0048] Figure 4 This is a schematic diagram of the module structure of the ionospheric inversion accuracy evaluation method apparatus according to an embodiment of this application;

[0049] Figure 5 This is a schematic diagram of the equipment structure of the hardware operating environment involved in the ionospheric inversion accuracy evaluation method in the embodiments of this application.

[0050] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0051] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0052] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0053] The main solution of this application embodiment is: to acquire observation data of the ionospheric inversion region through spaceborne synthetic aperture radar and extract the ionospheric electron content from the observation data; to input the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region; and to evaluate the accuracy of the ionospheric electron content based on the target ionospheric electron content.

[0054] Existing techniques for assessing the accuracy of SAR ionospheric inversion utilize SAR ionospheric inversion results to correct ionospheric errors in InSAR interferometry, evaluating the effectiveness of SAR ionospheric inversion based on the improvement in measurement accuracy. However, this assessment method is indirect and the accuracy of the results is not high.

[0055] This application transforms the pixel coordinates of synthetic aperture radar into ionospheric thin-layer coordinates, and compares the ionospheric inversion results of spaceborne synthetic aperture radar with the ionospheric results of global satellite navigation system within the same coordinate frame. This enables an effective assessment of the inversion accuracy of the ionosphere by spaceborne synthetic aperture radar, and improves the accuracy of SAR ionospheric inversion accuracy assessment compared with existing indirect assessment techniques.

[0056] Based on this, embodiments of this application provide a method for evaluating the accuracy of ionospheric inversion, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the ionospheric inversion accuracy assessment method of this application.

[0057] In this embodiment, the ionosphere inversion accuracy evaluation method includes steps S10 to S30:

[0058] Step S10: Obtain observation data of the ionospheric inversion region through spaceborne synthetic aperture radar, and extract the ionospheric electron content from the observation data.

[0059] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an ionospheric inversion accuracy evaluation device capable of performing the above functions. The following description uses an ionospheric inversion accuracy evaluation device as an example to illustrate this embodiment and the subsequent embodiments.

[0060] It should be noted that SAR (Synthetic Aperture Radar) is a modern, all-weather, all-time high-resolution microwave imaging radar. The ionosphere is a region of Earth's atmosphere, located at an altitude of approximately 60 to 1000 kilometers above the ground. It is primarily formed by the ionization of molecules and atoms in Earth's upper atmosphere under the influence of ultraviolet radiation, X-rays, and high-energy particles from the sun. This region is filled with free electrons and positive and negative ions, forming a plasma region that has a significant impact on radio communication, navigation, and radar detection. Ionospheric inversion refers to the process of deducing the physical parameters and structural characteristics of the ionosphere from various observational data using observational and data processing methods. Observational data includes SAR image scattering signals, sensor orbit files, and imaging geometry information.

[0061] Understandably, the sensor orbit file in the observation data includes the SAR sensor frequency, the SAR image scattering signal includes the radio wave vector, and the imaging geometry information includes the angle of the Earth's magnetic field and the total magnetic field strength of the Earth at an altitude of 350 km. In practical applications, the formula for calculating the ionospheric electron content can be obtained from the observation data using the Faraday rotation method.

[0062]

[0063] Where TEC is the ionospheric electron content, f0 is the SAR sensor frequency, B is the total magnetic field strength of the Earth at an altitude of 350 km, Ψ is the angle between the radio wave vector and the Earth's magnetic field, and Ω is the ionospheric electron content. T The FR (Faraday Rotation) value is a unidirectional transmission value. The ionospheric electron content in the observation data can be extracted using the formula for calculating the ionospheric electron content.

[0064] Step S20: Input the observation data into the preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region.

[0065] It should be noted that the ionospheric inversion region refers to the area where the SAR signal penetrates the thin ionospheric layer. This thin ionospheric layer is used to simplify the model, defining a single thin layer at an altitude of 250 to 450 km to represent the entire ionosphere. The preset ionospheric electron content calculation model can be established using GNSS (Global Navigation Satellite System) observation data to obtain the electron content. The target ionospheric electron content is a more accurate electron content obtained through the preset ionospheric electron content calculation model.

[0066] Step S30: Accuracy assessment of the ionospheric electron content based on the target ionospheric electron content.

[0067] It should be noted that the target ionospheric electron content is a more accurate value than the ionospheric electron content. The accuracy of the ionospheric electron content can be obtained through the target ionospheric electron content, and the precision of the ionospheric electron content can be evaluated.

[0068] In one feasible approach, step S30 includes:

[0069] The content difference of the ionosphere at each puncture point is determined based on the ionospheric electron content and the target ionospheric electron content.

[0070] Calculate the mean and / or root mean square error among the differences in content;

[0071] The accuracy of the ionospheric electron content is assessed based on the mean and / or the root mean square error.

[0072] Understandably, the target ionospheric electron content obtained by substituting the coordinates of the puncture point into the model is a more accurate value. The content difference at each puncture point can be obtained by comparing the actual observed ionospheric electron content with the target ionospheric electron content.

[0073] It's important to note that the mean is the sum of all values ​​in a set of data divided by the number of data points. The root mean square error (RMSE) is a commonly used metric to measure the difference between a model's predicted values ​​and the actual values. It is calculated by averaging the squares of the prediction errors and then taking the square root. A smaller RMSE indicates better predictive performance, meaning a smaller difference between the predicted and actual values. For example, if the differences in three content values ​​are a, b, and c, then the mean is (a+b+c) / 3, and the RMSE is...

[0074] Based on the mean and / or the root mean square error, the difference between the observed and predicted values ​​of ionospheric electron content can be obtained, and this difference can be used to assess the accuracy. The smaller the difference, the more accurate the observed value of ionospheric electron content.

[0075] In this embodiment, the ionospheric electron content obtained through SAR ionospheric inversion is obtained from observation data, and the target ionospheric electron content with higher accuracy is obtained through a preset ionospheric electron content calculation model. By using the target ionospheric electron content to evaluate the accuracy of the ionospheric electron content, the accuracy of the obtained ionospheric inversion accuracy evaluation result is higher.

[0076] Based on the first embodiment described above, a second embodiment of this application is proposed. In this embodiment, content that is the same as or similar to that in the first embodiment can be referred to the above description, and will not be repeated hereafter. Figure 2 Step S20 may include steps S201 to 203:

[0077] Step S201: Determine the latitude and longitude coordinates of the target pixel in the ground image.

[0078] It should be noted that ground images are compiled from different image information acquired by SAR at multiple times. Target pixels are the basic building blocks of ground images. The location of a target pixel can be determined by its row and column number. For example, the target pixel in the i-th row and j-th column is located at position G. ij Then the target pixel G ij The latitude and longitude coordinates are (B ij L ij ).

[0079] Step S202: Perform coordinate transformation on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point.

[0080] It should be noted that the ionospheric puncture point is the intersection point between the spaceborne synthetic aperture radar and the target pixel on the thin ionospheric layer. Transforming the latitude and longitude coordinates yields the coordinates of the ionospheric puncture point corresponding to the pixel.

[0081] In one feasible approach, the step of performing coordinate transformation on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point includes:

[0082] Extract the discrete point coordinates of the synthetic aperture radar's orbit from the observation data;

[0083] The target trajectory is obtained by fitting the trajectory based on the coordinates of the discrete points.

[0084] Based on the latitude and longitude coordinates and the orbital coordinates at the corresponding time on the target orbit, the pixel satellite elevation angle and azimuth angle of the synthetic aperture radar are calculated;

[0085] The coordinates of the ionospheric puncture point are calculated based on the latitude and longitude coordinates, the altitude angle, and the azimuth angle.

[0086] It should be noted that the observation data includes SAR orbit information, from which the coordinates of some discrete points can be obtained. These discrete point coordinates are the coordinates of the SAR at different times. Since the SAR's motion trajectory is a continuous trajectory, it is necessary to fit the SAR orbit using these discrete point coordinates to obtain the SAR orbit coordinates corresponding to the pixel acquisition time.

[0087] Understandably, interpolation methods can be used to process the coordinates of discrete points, resulting in an excessive number of orbital coordinates. For example, Hermite interpolation can be used. For instance, given the discrete point: a ≤ x0... <x1<...<x n ≤b,y j =f(x) j ), m j =f'(x j Given 2n+2 conditions (j = 0, 1, 2, ..., n), a polynomial of degree no more than 2n+1 can be uniquely determined and rewritten in the form of interpolation basis functions:

[0088]

[0089] in,

[0090]

[0091] Let the imaging times corresponding to the first row of the SAR image from the last row be t = [t1, t2, ..., t3]. n After orbital interpolation, the corresponding orbital positions S are as follows:

[0092]

[0093] It should be noted that the azimuth angle is the horizontal angle between the north-pointing line at a certain point and the target direction line in a clockwise direction. The elevation angle is the angle between the direction line from a point to the observed target and the horizontal plane.

[0094] The latitude and longitude coordinates of the puncture point can be obtained from the pixel's latitude and longitude coordinates, elevation angle, azimuth angle, and the geographic latitude and longitude formula of the puncture point:

[0095]

[0096] That is, the target pixel G nm The latitude and longitude coordinates of the corresponding puncture point.

[0097] The formula for the geographical latitude and longitude of the ionospheric puncture point can be obtained from the relationship of spherical triangles:

[0098]

[0099] Among them, (φ u , λ u Let χ be the latitude and longitude coordinates of the target pixel, χ be the geocentric subtended angle, and A be the azimuth angle of the target pixel. The formula for the geocentric subtended angle is:

[0100]

[0101] Where R is the Earth's radius, H is the height of the ionosphere, and E is the elevation angle of the target pixel. The elevation angle formula is:

[0102]

[0103] The formula for azimuth is:

[0104]

[0105] Among them, [X RS Y RS Z RS [This refers to the satellite's geocentric coordinates. Specifically, the satellite's geocentric coordinates are:]

[0106]

[0107] Where [X] R Y R Z R [BL] represents the spatial coordinates of the receiver, and [BL] represents the latitude and longitude coordinates of the receiver.

[0108] Step S203: Input the coordinates of the ionospheric puncture point into the preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

[0109] It should be noted that the variables in the preset ionospheric electron content calculation model are latitude and longitude coordinates. By inputting the latitude and longitude coordinates of the ionospheric puncture point into the model, the target ionospheric electron content can be obtained with higher accuracy.

[0110] In this embodiment, the pixel coordinates of SAR are transformed to obtain the coordinates of the ionospheric thin layer puncture point corresponding to the pixel. Then, the coordinates of the puncture point are input into the preset ionospheric electron content calculation model, which can obtain the target ionospheric electron content with higher accuracy.

[0111] Based on the second embodiment described above, a third embodiment of this application is proposed. In this embodiment, content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Figure 3 Before step S20, steps S01 to S03 may be included:

[0112] Step S01: Obtain observation data samples from the Global Navigation Satellite System.

[0113] It should be noted that GNSS (Global Navigation Satellite System) includes, but is not limited to, the Global Positioning System (GPS), GLONASS, BeiDou Navigation Satellite System (BDS), and Galileo. GNSS systems support multi-frequency observations, utilizing combinations of signals from different frequencies to eliminate or weaken the ionosphere's influence on positioning, significantly improving the accuracy of extracted ionospheric electron content. Furthermore, GNSS systems have global coverage capabilities, providing ionospheric observation data worldwide. This extensive coverage provides a rich data foundation for ionospheric inversion, helping to construct more accurate ionospheric models; therefore, relatively accurate ionospheric electron content can be obtained from GNSS systems. Observational data samples can include raw GNSS observation data, ephemeris files, differential code bias (DCB) files, etc.

[0114] Step S02: Based on the observed data sample, calculate the ionospheric electron content sample.

[0115] It should be noted that the process of calculating the ionospheric electron content sample based on the observed data sample involves calculating a portion of the data in the observed data sample using a formula, thereby obtaining the ionospheric electron content sample.

[0116] In one feasible approach, calculating the ionospheric electron content sample based on the observed data sample includes:

[0117] The observation data sample is smoothed to obtain the target observation data sample;

[0118] Based on the target observation data sample, the ionospheric electron content sample is calculated.

[0119] It should be noted that the smoothing process for the observed data samples mainly involves smoothing the pseudorange observations using phase observations. The purpose is to remove some useless data and obtain more accurate target observation data samples. The ionospheric electron content sample is a more accurate electron content obtained from GNSS observation data.

[0120] Understandably, the raw observation data in the target observation data sample includes different carrier signal frequencies, dual-frequency code combined ionospheric observation value P4, and differential code bias (DCB) files including satellite and receiver differential code bias DCBs. i With DCB j The formula for calculating the GNSS electron content can be obtained as follows:

[0121]

[0122] Where c is the speed of light in a vacuum, f1 and f2 are different carrier signal frequencies, P4 is the dual-frequency code combined ionospheric observation value, and DCB i With DCB j These represent the differential code offsets for the satellite and receiver, respectively. The ionospheric electron content sample can be obtained using the GNSS electron content calculation formula.

[0123] Step S03: Based on the observed data sample and the ionospheric electron content sample, establish a preset ionospheric electron content calculation model.

[0124] Understandably, the original observation data in the observation data sample includes the geographic latitude of the puncture point, the diurnal longitude of the puncture point, the geographic longitude of the puncture point, and the solar geographic longitude. A pre-defined ionospheric electron content calculation model can be constructed using spherical harmonic functions based on the ionospheric electron content sample and the aforementioned observation data sample.

[0125]

[0126] Where β is the geographic latitude of the puncture point, s is the solar longitude of the puncture point, s=λ-λ0, λ is the geographic longitude of the puncture point, λ0 is the solar longitude, and a nm and b nm The coefficients of the ionospheric model can be obtained from ionospheric electron content samples. nm and b nm , Let n denote the orthogonalized association Legendre function. max This represents the maximum order of the spherical harmonic function.

[0127] This embodiment calculates ionospheric electron content samples using GNSS observation data samples and constructs a preset ionospheric electron content calculation model. By inputting the latitude and longitude coordinates of any puncture point into this model, an accurate ionospheric content value can be obtained. Comparing the actual measured ionospheric content value with the accurate ionospheric content value obtained from the model can effectively evaluate the ionospheric inversion accuracy and improve the accuracy of SAR ionospheric inversion accuracy assessment.

[0128] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the ionospheric inversion accuracy evaluation method of this application. Any simple transformations based on this technical concept are within the protection scope of this application.

[0129] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of the workflow to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here.

[0130] In addition, for technical details not described in detail in this embodiment, please refer to the business system architecture diagram generation method provided in any embodiment of the present invention, which will not be repeated here.

[0131] Furthermore, it should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0132] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0133] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0134] This application also provides an ionospheric inversion accuracy evaluation device, please refer to... Figure 4 The ionospheric inversion accuracy evaluation device includes:

[0135] The acquisition module 10 is used to acquire observation data of the ionospheric inversion region through spaceborne synthetic aperture radar and extract the ionospheric electron content from the observation data.

[0136] The calculation module 20 is used to input the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region.

[0137] The evaluation module 30 is used to perform an accuracy evaluation of the ionospheric electron content based on the target ionospheric electron content.

[0138] In one embodiment, the calculation module 20 is further configured to determine the latitude and longitude coordinates of the target pixel in the ground image; perform coordinate transformation on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point, wherein the ionospheric puncture point is the intersection point between the spaceborne synthetic aperture radar and the target pixel on the thin layer of the ionosphere; and input the coordinates of the ionospheric puncture point into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

[0139] In one embodiment, the calculation module 20 is further configured to extract discrete point coordinates of the synthetic aperture radar's orbit from the observation data; perform orbit fitting based on the discrete point coordinates to obtain the target orbit; calculate the pixel satellite elevation angle and azimuth angle of the synthetic aperture radar according to the latitude and longitude coordinates and the orbit coordinates at the corresponding time on the target orbit; and calculate the coordinates of the ionospheric puncture point according to the latitude and longitude coordinates, the elevation angle, and the azimuth angle.

[0140] In one embodiment, the calculation module 20 is further configured to perform interpolation processing on the discrete point coordinates to obtain target discrete point coordinates, wherein the number of target discrete point coordinates is greater than the number of discrete point coordinates; correspondingly, the step of performing orbit fitting based on the discrete point coordinates to obtain the target orbit includes: performing orbit fitting based on the target discrete point coordinates to obtain the target orbit.

[0141] In one embodiment, the calculation module 30 is further configured to determine the content difference of each puncture point of the ionosphere based on the ionospheric electron content and the target ionospheric electron content; calculate the mean and / or root mean square error between each content difference; and perform an accuracy assessment of the ionospheric electron content based on the mean and / or the root mean square error.

[0142] In one embodiment, the ionospheric inversion accuracy assessment device further includes a modeling module 40, used to acquire observation data samples from a global navigation satellite system; calculate an ionospheric electron content sample based on the observation data samples; and establish a preset ionospheric electron content calculation model based on the observation data samples and the ionospheric electron content sample.

[0143] In one embodiment, the modeling module 40 is used to smooth the observation data sample to obtain a target observation data sample; and to calculate an ionospheric electron content sample based on the target observation data sample.

[0144] In this embodiment, the ionospheric electron content obtained through SAR ionospheric inversion is obtained from observation data, and the target ionospheric electron content with higher accuracy is obtained through a preset ionospheric electron content calculation model. By using the target ionospheric electron content to evaluate the accuracy of the ionospheric electron content, the accuracy of the obtained ionospheric inversion accuracy evaluation result is higher.

[0145] The ionospheric inversion accuracy assessment device provided in this application, employing the ionospheric inversion accuracy assessment method described in the above embodiments, can solve the technical problem of low accuracy in SAR ionospheric inversion accuracy assessment. Compared with the prior art, the beneficial effects of the ionospheric inversion accuracy assessment device provided in this application are the same as those of the ionospheric inversion accuracy assessment method provided in the above embodiments, and other technical features in the ionospheric inversion accuracy assessment device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0146] This application provides an ionospheric inversion accuracy evaluation device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the ionospheric inversion accuracy evaluation method in Embodiment 1 above.

[0147] The following is for reference. Figure 5 This document illustrates a structural schematic diagram of an ionospheric inversion accuracy assessment device suitable for implementing embodiments of this application. The ionospheric inversion accuracy assessment device in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 5 The ionospheric inversion accuracy assessment device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0148] like Figure 5As shown, the ionospheric inversion accuracy assessment device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the ionospheric inversion accuracy assessment device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the ionospheric inversion accuracy assessment equipment to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows an ionospheric inversion accuracy assessment equipment with various systems, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems can be implemented alternatively.

[0149] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0150] The ionospheric inversion accuracy assessment device provided in this application, employing the ionospheric inversion accuracy assessment method described in the above embodiments, can solve the technical problem of low accuracy in ionospheric inversion accuracy assessment. Compared with the prior art, the beneficial effects of the ionospheric inversion accuracy assessment device provided in this application are the same as those of the ionospheric inversion accuracy assessment method provided in the above embodiments, and other technical features in this ionospheric inversion accuracy assessment device are the same as those disclosed in the method of the previous embodiment, and will not be repeated here.

[0151] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0152] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0153] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the ionospheric inversion accuracy evaluation method in the above embodiments.

[0154] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0155] The aforementioned computer-readable storage medium may be included in the ionospheric inversion accuracy assessment device; or it may exist independently and not be assembled into the ionospheric inversion accuracy assessment device.

[0156] The aforementioned computer-readable storage medium carries one or more programs. When these programs are executed by the ionospheric inversion accuracy assessment device, the ionospheric inversion accuracy assessment device: acquires observation data of the ionospheric inversion region through a spaceborne synthetic aperture radar and extracts the ionospheric electron content from the observation data; inputs the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region; and performs an accuracy assessment of the ionospheric electron content based on the target ionospheric electron content.

[0157] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0158] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0159] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0160] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described ionospheric inversion accuracy assessment method, thereby solving the technical problem of low accuracy in ionospheric inversion accuracy assessment. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the ionospheric inversion accuracy assessment method provided in the above embodiments, and will not be repeated here.

[0161] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the ionospheric inversion accuracy evaluation method described above.

[0162] The computer program product provided in this application can solve the technical problem of low accuracy in ionospheric inversion accuracy assessment. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the ionospheric inversion accuracy assessment method provided in the above embodiments, and will not be repeated here.

[0163] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for evaluating the accuracy of ionospheric inversion, characterized in that, The method includes: Observational data of the ionospheric inversion region were acquired using a spaceborne synthetic aperture radar, and the ionospheric electron content in the observational data was extracted. The observation data is input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region. The accuracy of the ionospheric electron content is evaluated based on the target ionospheric electron content. The observation data includes at least ground images; The observed data is input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content, including: Determine the latitude and longitude coordinates of the target pixels in the ground image; The latitude and longitude coordinates are transformed to obtain the coordinates of the ionospheric puncture point, which is the intersection of the spaceborne synthetic aperture radar and the target pixel on the thin layer of the ionosphere. The coordinates of the ionospheric puncture point are input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

2. The method as described in claim 1, characterized in that, The step of performing coordinate transformation on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point includes: Extract the discrete point coordinates of the synthetic aperture radar's orbit from the observation data; The target trajectory is obtained by fitting the trajectory based on the coordinates of the discrete points. Based on the latitude and longitude coordinates and the orbital coordinates at the corresponding time on the target orbit, the pixel satellite elevation angle and azimuth angle of the synthetic aperture radar are calculated; The coordinates of the ionospheric puncture point are calculated based on the latitude and longitude coordinates, the altitude angle, and the azimuth angle.

3. The method as described in claim 2, characterized in that, Before performing trajectory fitting based on the discrete point coordinates to obtain the target trajectory, the process further includes: Interpolation is performed on the discrete point coordinates to obtain the target discrete point coordinates, wherein the number of target discrete point coordinates is greater than the number of discrete point coordinates. Accordingly, the step of fitting the target orbit based on the discrete point coordinates includes: The target trajectory is obtained by fitting the trajectory based on the coordinates of the target discrete points.

4. The method as described in claim 1, characterized in that, Before the step of inputting the observed data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content, the following steps are included: Acquire observation data samples from the Global Navigation Satellite System; Based on the observed data sample, the ionospheric electron content sample was calculated; Based on the observed data samples and the ionospheric electron content samples, a preset ionospheric electron content calculation model is established.

5. The method as described in claim 4, characterized in that, The calculation of the ionospheric electron content sample based on the observed data sample includes: The observation data sample is smoothed to obtain the target observation data sample; Based on the target observation data sample, the ionospheric electron content sample is calculated.

6. The method as described in claim 1, characterized in that, The step of accurately assessing the ionospheric electron content based on the target ionospheric electron content includes: The content difference of the ionosphere at each puncture point is determined based on the ionospheric electron content and the target ionospheric electron content. Calculate the mean and / or root mean square error among the differences in content; The accuracy of the ionospheric electron content is assessed based on the mean and / or the root mean square error.

7. An ionospheric inversion accuracy evaluation device, characterized in that, The ionosphere inversion accuracy evaluation device includes: The acquisition module is used to acquire observational data of the ionospheric inversion region through a spaceborne synthetic aperture radar and extract the ionospheric electron content from the observational data. The calculation module is used to input the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion region; The evaluation module is used to perform an accuracy evaluation of the ionospheric electron content based on the target ionospheric electron content; The observation data includes at least ground images; The observed data is input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content, including: Determine the latitude and longitude coordinates of the target pixels in the ground image; The latitude and longitude coordinates are transformed to obtain the coordinates of the ionospheric puncture point, which is the intersection of the spaceborne synthetic aperture radar and the target pixel on the thin layer of the ionosphere. The coordinates of the ionospheric puncture point are input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

8. An ionospheric inversion accuracy assessment device, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the ionospheric inversion accuracy assessment method as described in any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the ionospheric inversion accuracy evaluation method as described in any one of claims 1 to 6.

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