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

Abstract

The invention discloses an ionosphere inversion precision evaluation method, device and equipment and a storage medium, and relates to the technical field of ionosphere detection, and the method comprises the steps: obtaining observation data of an ionosphere inversion region through a spaceborne synthetic aperture radar, and extracting the ionosphere electron content in the observation data; inputting the observation data into a preset ionosphere electron content calculation model to obtain a target ionosphere electron content of the ionosphere inversion region; and carrying out precision evaluation on the ionized layer electron content based on the target ionized layer electron content. According to the invention, the precision of the satellite-borne synthetic aperture radar inversion ionized layer is evaluated through a high-precision ionized layer result obtained through inversion of a global navigation satellite system technology; and the precision of inversion of the ionosphere by the spaceborne synthetic aperture radar can be evaluated more accurately.

Description

Technical Field

[0001] The present application relates to the field of ionospheric detection technology, and in particular to an ionospheric inversion accuracy assessment method, device, equipment and storage medium. Background Art

[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, and can obtain more precise total electron content in the ionosphere. The evaluation of the accuracy of SAR inversion of the ionosphere is also indispensable, and the accuracy of the ionospheric inversion results can be judged by the evaluation results. The existing technology for evaluating the accuracy of SAR inversion of the ionosphere is to use the SAR ionospheric inversion results to correct the ionospheric errors in InSAR (Interferometric Synthetic Aperture Radar) interferometric measurement, and evaluate the effectiveness of SAR ionospheric inversion by measuring the accuracy. However, this evaluation method is an indirect evaluation, and the accuracy of the evaluation results is not high.

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

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of this application is to provide an ionospheric inversion accuracy assessment method, device, equipment and storage medium, aiming to solve the technical problem of how to improve the accuracy of ionospheric inversion accuracy assessment.

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

[0007] Acquiring observation data of the ionospheric inversion region through a spaceborne synthetic aperture radar, and extracting the ionospheric electron content in the observation data;

[0008] Inputting the observed data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content in the ionospheric inversion region;

[0009] An accuracy assessment is performed on the ionospheric electron content based on the target ionospheric electron content.

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

[0011] Inputting the observed data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content includes:

[0012] Determining the latitude and longitude coordinates of the target pixel in the ground image;

[0013] The latitude and longitude coordinates are converted to obtain the coordinates of the ionospheric puncture point, where the ionospheric puncture point is the intersection between the spaceborne synthetic aperture radar and the target pixel on the ionospheric thin layer;

[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 performing coordinate conversion on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point includes:

[0016] Extracting the coordinates of discrete points of the synthetic aperture radar track in the observation data;

[0017] Perform orbit fitting based on the discrete point coordinates to obtain a target orbit;

[0018] Calculating the satellite pixel altitude angle and azimuth angle of the synthetic aperture radar according to the latitude and longitude coordinates and the orbital coordinates of the target orbit at the corresponding time;

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

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

[0021] Performing interpolation processing on the discrete point coordinates to obtain target discrete point coordinates, wherein the number of the target discrete point coordinates is greater than the number of the discrete point coordinates;

[0022] Accordingly, performing orbit fitting based on the discrete point coordinates to obtain a target orbit includes:

[0023] The target orbit is obtained by performing orbit fitting 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 a target ionospheric electron content, the step includes:

[0025] Obtaining samples of observation data from global navigation satellite systems;

[0026] Based on the observation data sample, an ionospheric electron content sample is calculated;

[0027] A preset ionospheric electron content calculation model is established based on the observation data samples and the ionospheric electron content samples.

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

[0029] Performing smoothing on the observed data samples to obtain target observed data samples;

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

[0031] In one embodiment, the step of performing accuracy assessment on the ionospheric electron content based on the target ionospheric electron content comprises:

[0032] Determining the content difference of each ionospheric puncture point according to the ionospheric electron content and the target ionospheric electron content;

[0033] Calculate the mean and / or root mean square error between each content difference;

[0034] The accuracy of the ionospheric electron content is evaluated according to the mean value and / or the root mean square error.

[0035] In addition, to achieve the above purpose, the present application also proposes an ionospheric inversion accuracy assessment device, the ionospheric inversion accuracy assessment device comprising:

[0036] An acquisition module, used to acquire observation data of the ionospheric inversion area through a spaceborne synthetic aperture radar, and extract the ionospheric electron content in the observation data;

[0037] A calculation module, used for inputting the observation data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content in the ionospheric inversion region;

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

[0039] In addition, to achieve the above-mentioned purpose, the present application also proposes an ionospheric inversion accuracy assessment device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the ionospheric inversion accuracy assessment method as described above.

[0040] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which 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, the steps of the ionospheric inversion accuracy assessment method as described above are implemented.

[0041] The present application provides an ionospheric inversion accuracy assessment method. The present application first obtains observation data of an ionospheric inversion region through a spaceborne synthetic aperture radar, and extracts the ionospheric electron content in the observation data; inputs the observation data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content in the ionospheric inversion region; and performs an accuracy assessment of the ionospheric electron content based on the target ionospheric electron content.

[0042] In summary, the present application converts the pixel coordinates of the synthetic aperture radar into the ionospheric thin layer coordinates, places the ionospheric inversion results of the spaceborne synthetic aperture radar and the ionospheric results of the global satellite navigation system in the same coordinate frame for comparison, and can directly realize the effective evaluation of the inversion accuracy of the spaceborne synthetic aperture radar ionosphere. Compared with the existing indirect evaluation technology, the accuracy of the ionospheric inversion accuracy evaluation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0045] Figure 1 This is a flow chart of the first embodiment of the ionospheric inversion accuracy assessment method of the present application;

[0046] Figure 2 This is a flow chart of the second embodiment of the ionospheric inversion accuracy assessment method of the present application;

[0047] Figure 3 This is a flow chart of the third embodiment of the ionospheric inversion accuracy assessment method of the present application;

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

[0049] Figure 5 Schematic diagram of the device structure of the hardware operating environment involved in the ionospheric inversion accuracy assessment method in the embodiment of the present application.

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

[0051] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0052] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0053] The main solution of the embodiment of the present application is: obtaining observation data of the ionospheric inversion area through a space-borne synthetic aperture radar, and extracting the ionospheric electron content in the observation data; inputting the observation data into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content of the ionospheric inversion area; and performing accuracy assessment of the ionospheric electron content based on the target ionospheric electron content.

[0054] The existing technology for evaluating the accuracy of SAR inversion of the ionosphere is to use the SAR ionosphere inversion results to correct the ionosphere error in InSAR interferometry, and evaluate the effectiveness of SAR ionosphere inversion by measuring the improvement effect of accuracy. However, this evaluation method is an indirect evaluation, and the accuracy of the evaluation results is not high.

[0055] The present application converts the pixel coordinates of synthetic aperture radar into ionospheric thin layer coordinates, places the ionospheric inversion results of spaceborne synthetic aperture radar and the ionospheric results of global satellite navigation system in the same coordinate frame for comparison, and can realize effective evaluation of the inversion accuracy of spaceborne synthetic aperture radar ionosphere. Compared with the existing indirect evaluation technology, the accuracy of SAR ionospheric inversion accuracy evaluation is improved.

[0056] Based on this, the present application embodiment provides an ionospheric inversion accuracy assessment method, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the ionospheric inversion accuracy assessment method of the present application.

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

[0058] Step S10: obtaining observation data of the ionospheric inversion region through a spaceborne synthetic aperture radar, and extracting the ionospheric electron content in the observation data.

[0059] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an ionospheric inversion accuracy assessment device capable of realizing the above functions, etc. The following takes the ionospheric inversion accuracy assessment device as an example to illustrate this embodiment and the following embodiments.

[0060] It should be noted that SAR (Synthetic Aperture Radar) is a modern high-resolution microwave imaging radar that is available all day and all night. The ionosphere is a region of the Earth's atmosphere, located in an altitude range of about 60 to 1,000 kilometers from the ground. It is mainly formed by the ionization of molecules and atoms in the Earth's upper atmosphere under the action of ultraviolet rays, X-rays and high-energy particles from the sun. This region is full of free electrons and positive and negative ions, forming a plasma region, which has an important impact on radio communications, navigation, and radar detection. Ionospheric inversion refers to the process of inferring the physical parameters and structural characteristics of the ionosphere from various observation data of the ionosphere through observation and data processing. Observation data include SAR image scattering signals, sensor orbit files, imaging geometry information, etc.

[0061] It can be understood that the sensor orbit file in the observation data includes the SAR sensor frequency, the SAR image scattering signal includes the radio wave vector, 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 kilometers. In practical applications, the ionospheric electron content calculation formula can be obtained by the Faraday rotation method through the observation data:

[0062]

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

[0064] Step S20: inputting the observed data into a 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 puncture area of ​​the SAR signal on the thin layer of the ionosphere, and the thin layer of the ionosphere is to simplify the model, and a single thin layer is defined at an altitude of 250 to 450 km from the ground to replace the entire ionosphere. The preset ionospheric electron content calculation model can be a model established through GNSS (Global Navigation Satellite System) observation data to obtain the electron content. The target ionospheric electron content is a more accurate electron content obtained by the preset ionospheric electron content calculation model.

[0066] Step S30: performing accuracy assessment on 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 content, and the accuracy of the ionospheric electron content can be evaluated.

[0068] In a feasible manner, step S30 includes:

[0069] Determining the content difference of each ionospheric puncture point according to the ionospheric electron content and the target ionospheric electron content;

[0070] Calculate the mean and / or root mean square error between each content difference;

[0071] The accuracy of the ionospheric electron content is evaluated according to the mean value and / or the root mean square error.

[0072] It can be understood that the target ionospheric electron content obtained by substituting the coordinates of the puncture point into the model is a more accurate value, and the content difference at each puncture point can be obtained by the actually observed ionospheric electron content and the target ionospheric electron content.

[0073] It should be noted that the mean is the sum of all the values ​​in a set of data divided by the number (or number) of data in this set. The root mean square error is a common indicator to measure the difference between the model prediction value and the true value. It is obtained by averaging the squares of the prediction errors and then taking the square root. The smaller the root mean square error, the better the prediction performance of the model, that is, the smaller the difference between the predicted value and the actual value. For example, if the three content differences are a, b, and c, the mean is (a+b+c) / 3, and the root mean square error is

[0074] Based on the mean value and / or the root mean square error result, the difference between the observed value and the predicted value of the ionospheric electron content can be obtained to perform accuracy assessment. The smaller the difference, the more accurate the observed value of the ionospheric electron content is.

[0075] In this embodiment, the ionospheric electron content of SAR ionospheric inversion is obtained by observation data, and the target ionospheric electron content with higher accuracy is obtained by presetting the ionospheric electron content calculation model. The accuracy of the ionospheric electron content is evaluated by the target ionospheric electron content, and the accuracy of the ionospheric inversion accuracy evaluation result is higher.

[0076] Based on the above first embodiment, a second embodiment of the present application is proposed. In this embodiment, the same or similar contents as those of the above first embodiment can be referred to the above introduction, and will not be repeated later. Figure 2 , the step S20 may include steps S201 to S203:

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

[0078] It should be noted that the ground image is a collection of different image information collected by SAR at multiple times. The target pixel is the basic component unit of the ground image. The position of the target pixel can be determined by the row and column number of the target pixel. For example, the position of the target pixel in the i-th row and j-th column is G ij , then the target pixel G ij The longitude and latitude coordinates are (B ij , L ij ).

[0079] Step S202: performing coordinate conversion 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 ionospheric thin layer. The coordinates of the ionospheric puncture point corresponding to the pixel are obtained by converting the longitude and latitude coordinates.

[0081] In a feasible manner, the converting the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point includes:

[0082] Extracting the coordinates of discrete points of the synthetic aperture radar track in the observation data;

[0083] Perform orbit fitting based on the discrete point coordinates to obtain a target orbit;

[0084] Calculating the satellite pixel altitude angle and azimuth angle of the synthetic aperture radar according to the latitude and longitude coordinates and the orbital coordinates of the target orbit at the corresponding time;

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

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

[0087] It is understandable that the coordinates of the discrete points can be processed using interpolation methods to obtain an excessive number of orbital coordinates, for example, using the Hermite interpolation method, for example: Assume that the discrete point is known: a≤x0 <x1<...<x n ≤ b,y j =f(x j ), m j =f'(x j ), (j = 0, 1, 2..., n), given 2n+2 conditions, a polynomial with a degree not exceeding 2n+1 can be uniquely determined and rewritten as an interpolation basis function:

[0088]

[0089] in,

[0090]

[0091] Assume that the imaging time corresponding to the first row to the last row of the SAR image is t = [t1, t2, ..., t n ], the corresponding orbital positions S after orbital interpolation are:

[0092]

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

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

[0095]

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

[0097] The geographical longitude and latitude formula of the ionospheric piercing point can be obtained based on the spherical triangle relationship:

[0098]

[0099] Among them, (φ u ,λ u ) is the latitude and longitude coordinates of the target pixel, χ is the geocentric angle, A is the azimuth of the target pixel, and the geocentric angle formula is:

[0100]

[0101] Among them, R is the radius of the earth, H is the height of the ionosphere, and E is the altitude angle of the target pixel. The altitude angle formula is:

[0102]

[0103] The azimuth formula is:

[0104]

[0105] Among them, [X RS , Y RS , Z RS ] is the satellite station center coordinates. Specifically, the satellite station center coordinates are:

[0106]

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

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

[0109] It should be noted that the variables of the preset ionospheric electron content calculation model are longitude and latitude coordinates. By inputting the longitude and latitude coordinates of the ionospheric piercing point into the model, a more accurate target ionospheric electron content can be obtained.

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

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

[0112] Step S01: Acquire observation data samples from a 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 Satellite Navigation System (BDS) and Galileo Positioning System (Galileo). The GNSS system supports multi-frequency observation and can use a combination of signals of different frequencies to eliminate or weaken the influence of the ionosphere on positioning, significantly improving the accuracy of the extracted ionospheric electron content. In addition, the GNSS system has the ability to cover the world and can provide ionospheric observation data worldwide. This wide coverage provides a rich data basis for ionospheric inversion and helps to build a more accurate ionospheric model, so a relatively accurate ionospheric electron content can be obtained from the GNSS system. Observation data samples can be GNSS original observation data, ephemeris files, differential code deviation (DCB) files, etc.

[0114] Step S02: Based on the observation data sample, an ionospheric electron content sample is calculated.

[0115] It should be noted that the process of calculating the ionospheric electron content sample based on the observed data sample is to calculate part of the data in the observed data sample through a formula to obtain the ionospheric electron content sample.

[0116] In a feasible manner, the calculating and obtaining the ionospheric electron content sample based on the observation data sample includes:

[0117] Performing smoothing on the observed data samples to obtain target observed data samples;

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

[0119] It should be noted that the smoothing process of the observation data samples is mainly to smooth the pseudo-range observation values ​​through the phase observation values, the purpose of which 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 the GNSS observation data.

[0120] It can be understood that the original observation data in the target observation data sample includes different carrier signal frequencies, dual-frequency code combined ionospheric observation value P4, and differential code deviation (DCB) file including differential code deviation DCB of satellite and receiver i With DCB j , we can get the calculation formula of GNSS electronic content:

[0121]

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

[0123] Step S03: establishing a preset ionospheric electron content calculation model according to the observation data samples and the ionospheric electron content samples.

[0124] It is understandable that the original observation data in the observation data sample includes the geographical latitude of the puncture point, the solar longitude of the puncture point, the geographical longitude of the puncture point and the solar geographical longitude. The ionospheric electron content calculation model can be constructed using spherical harmonics through the ionospheric electron content sample and the observation data sample:

[0125]

[0126] Among them, β is the geographical latitude of the puncture point, s is the solar longitude of the puncture point, s = λ-λ0, λ is the geographical longitude of the puncture point, λ0 is the solar geographical longitude, a nm and b nm is the coefficient of the ionosphere model, which can be obtained by using the ionosphere electron content sample. nm and b nm , represents the orthogonalized associated Legendre function, n max Represents the maximum order of spherical harmonics.

[0127] This embodiment calculates the ionospheric electron content samples through the GNSS observation data samples, constructs a preset ionospheric electron content calculation model, and inputs the latitude and longitude coordinates of any puncture point into this model to obtain an accurate ionospheric content value. The ionospheric content value actually measured is compared with the accurate ionospheric content value obtained by the model, which can effectively evaluate the ionospheric inversion accuracy and improve the accuracy of SAR ionospheric inversion accuracy evaluation.

[0128] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the ionospheric inversion accuracy assessment method of the present application. More forms of simple transformations based on this technical concept are all within the scope of protection of the present application.

[0129] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0130] In addition, for technical details that are not described in detail in this embodiment, reference can be made to the method for generating a business system architecture diagram provided in any embodiment of the present invention, and will not be repeated here.

[0131] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0132] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0133] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an 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, which is stored in a storage medium (such as a read-only memory (ROM) / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0134] This application also provides an ionospheric inversion accuracy assessment device, please refer to Figure 4 , the ionospheric inversion accuracy assessment device comprises:

[0135] The acquisition module 10 is used to acquire the observation data of the ionospheric inversion area through the space-borne synthetic aperture radar, and extract the ionospheric electron content in 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 in the ionospheric inversion area.

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

[0138] In one embodiment, the calculation module 20 is further used to determine the longitude and latitude coordinates of the target pixel in the ground image; perform coordinate conversion on the longitude and latitude coordinates to obtain the coordinates of the ionospheric puncture point, where the ionospheric puncture point is the intersection point between the satellite-borne synthetic aperture radar and the target pixel on the ionospheric thin layer; 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 also used to extract the discrete point coordinates of the orbit of the synthetic aperture radar in the observation data; perform orbit fitting based on the discrete point coordinates to obtain the target orbit; calculate the pixel satellite altitude angle and azimuth angle of the synthetic aperture radar according to the longitude and latitude coordinates and the orbital coordinates at the corresponding time on the target orbit; calculate the coordinates of the ionospheric puncture point according to the longitude and latitude coordinates, the altitude angle and the azimuth angle.

[0140] In one embodiment, the calculation module 20 is also used to perform interpolation processing on the discrete point coordinates to obtain target discrete point coordinates, and the number of the target discrete point coordinates is greater than the number of the discrete point coordinates; accordingly, 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 used to determine the content difference of each ionospheric puncture point 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 accuracy assessment on 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 also includes a modeling module 40, which is used to obtain observation data samples from a global navigation satellite system; based on the observation data samples, calculate the ionospheric electron content samples; and establish a preset ionospheric electron content calculation model based on the observation data samples and the ionospheric electron content samples.

[0143] In one embodiment, the modeling module 40 is used to perform smoothing processing on the observation data samples to obtain target observation data samples; and calculate the ionospheric electron content samples based on the target observation data samples.

[0144] In this embodiment, the ionospheric electron content of SAR ionospheric inversion is obtained by observation data, and the target ionospheric electron content with higher accuracy is obtained by presetting the ionospheric electron content calculation model. The accuracy of the ionospheric electron content is evaluated by the target ionospheric electron content, and the accuracy of the ionospheric inversion accuracy evaluation result is higher.

[0145] The ionospheric inversion accuracy assessment device provided by the present application adopts the ionospheric inversion accuracy assessment method in the above embodiment, which can solve the technical problem that the accuracy of SAR ionospheric inversion accuracy assessment is not high. Compared with the prior art, the beneficial effects of the ionospheric inversion accuracy assessment device provided by the present application are the same as the beneficial effects of the ionospheric inversion accuracy assessment method provided by the above embodiment, and other technical features in the ionospheric inversion accuracy assessment device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0146] The present application provides an ionospheric inversion accuracy assessment 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 so that the at least one processor can execute the ionospheric inversion accuracy assessment method in the above-mentioned embodiment one.

[0147] Reference below Figure 5 , which shows a schematic diagram of the structure of an ionospheric inversion accuracy assessment device suitable for implementing the embodiment of the present application. The ionospheric inversion accuracy assessment device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 5 The ionospheric inversion accuracy assessment device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0148] like Figure 5As shown, the ionospheric inversion accuracy assessment device may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the ionospheric inversion accuracy assessment device are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems may be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 may allow the ionospheric inversion accuracy assessment device to communicate wirelessly or by wire with other devices to exchange data. Although the figure shows an ionospheric inversion accuracy assessment device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0149] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

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

[0151] It should be understood that the various parts disclosed in this application can be implemented by 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 one or more embodiments or examples in a suitable manner.

[0152] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0153] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the ionospheric inversion accuracy assessment method in the above-mentioned embodiment.

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

[0155] The computer-readable storage medium may be included in the ionospheric inversion accuracy assessment device; or may exist independently without being assembled into the ionospheric inversion accuracy assessment device.

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

[0157] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0158] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0159] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0160] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned ionospheric inversion accuracy assessment method, and can solve the technical problem that the accuracy of ionospheric inversion accuracy assessment is not high. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the ionospheric inversion accuracy assessment method provided in the above-mentioned embodiment, and will not be repeated here.

[0161] The present application also provides a computer program product, including a computer program, which implements the steps of the above-mentioned ionospheric inversion accuracy assessment method when executed by a processor.

[0162] The computer program product provided by the present application can solve the technical problem of low accuracy of ionospheric inversion accuracy assessment. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the ionospheric inversion accuracy assessment method provided by the above embodiment, which will not be described in detail here.

[0163] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for evaluating ionospheric inversion accuracy, characterized in that: The method comprises: Acquiring observation data of the ionospheric inversion region through a spaceborne synthetic aperture radar, and extracting the ionospheric electron content in the observation data; Inputting the observed data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content in the ionospheric inversion region; An accuracy assessment is performed on the ionospheric electron content based on the target ionospheric electron content.

2. The method according to claim 1, characterized in that The observation data at least includes ground images; Inputting the observed data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content includes: Determining the latitude and longitude coordinates of the target pixel in the ground image; The latitude and longitude coordinates are converted to obtain the coordinates of the ionospheric puncture point, where the ionospheric puncture point is the intersection between the spaceborne synthetic aperture radar and the target pixel on the ionospheric thin layer; The coordinates of the ionospheric puncture point are input into a preset ionospheric electron content calculation model to obtain the target ionospheric electron content.

3. The method according to claim 2, characterized in that The step of performing coordinate conversion on the latitude and longitude coordinates to obtain the coordinates of the ionospheric puncture point comprises: Extracting the coordinates of discrete points of the synthetic aperture radar track in the observation data; Perform orbit fitting based on the discrete point coordinates to obtain a target orbit; Calculating the satellite pixel altitude angle and azimuth angle of the synthetic aperture radar according to the latitude and longitude coordinates and the orbital coordinates of the target orbit at the corresponding time; The coordinates of the ionospheric puncture point are calculated according to the latitude and longitude coordinates, the altitude angle and the azimuth angle.

4. The method according to claim 3, characterized in that Before performing orbit fitting based on the discrete point coordinates to obtain the target orbit, the method further includes: Performing interpolation processing on the discrete point coordinates to obtain target discrete point coordinates, wherein the number of the target discrete point coordinates is greater than the number of the discrete point coordinates; Accordingly, performing orbit fitting based on the discrete point coordinates to obtain a target orbit includes: The target orbit is obtained by performing orbit fitting based on the coordinates of the target discrete points.

5. The method according to claim 1, characterized in that Before the step of inputting the observed data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content, the method further comprises: Obtaining samples of observation data from global navigation satellite systems; Based on the observation data sample, an ionospheric electron content sample is calculated; A preset ionospheric electron content calculation model is established based on the observation data samples and the ionospheric electron content samples.

6. The method according to claim 5, characterized in that The step of calculating the ionospheric electron content sample based on the observation data sample comprises: Performing smoothing on the observed data samples to obtain target observed data samples; Based on the target observation data sample, an ionospheric electron content sample is calculated.

7. The method according to claim 1, characterized in that The step of performing accuracy assessment on the ionospheric electron content based on the target ionospheric electron content comprises: Determining the content difference of each ionospheric puncture point according to the ionospheric electron content and the target ionospheric electron content; Calculate the mean and / or root mean square error between each content difference; The accuracy of the ionospheric electron content is evaluated according to the mean value and / or the root mean square error.

8. An ionospheric inversion accuracy assessment device, characterized in that: The ionospheric inversion accuracy assessment device comprises: An acquisition module, used to acquire observation data of the ionospheric inversion area through a spaceborne synthetic aperture radar, and extract the ionospheric electron content in the observation data; A calculation module, used for inputting the observation data into a preset ionospheric electron content calculation model to obtain a target ionospheric electron content in the ionospheric inversion region; An evaluation module is used to perform accuracy evaluation on the ionospheric electron content based on the target ionospheric electron content.

9. An ionospheric inversion accuracy assessment device, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the ionospheric inversion accuracy assessment method according to any one of claims 1 to 7.

10. 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, the steps of the ionospheric inversion accuracy assessment method according to any one of claims 1 to 7 are implemented.

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