Novel GNSS-IR elevation angle deviation correction method and system

Abstract

The invention provides a novel GNSS-IR elevation angle deviation correction method and system, and relates to the technical field of data processing, and the method comprises the steps: building a novel elevation angle deviation correction method taking electron density as a reference through a refraction angle relation; generating an SNR file, wherein the SNR file contains pseudo-random noise codes, azimuth angles, elevation angles and S1C observation value data of about 15000 epochs in one day; acquiring a satellite zenith distance and a position of an ionosphere puncture point by using a Krounberg model, and inputting the satellite zenith distance and the position of the ionosphere puncture point into a Nequick-G model to calculate and obtain electron density; the electron density and the satellite zenith distance are used as input parameters to be input into the novel elevation angle deviation correction method to obtain angle errors, the elevation angle is corrected, and the sea surface height is calculated according to the corrected elevation angle. The precision and reliability of sea surface height measurement are improved.

Description

Technical Field

[0001] The present invention relates to the field of data processing technology, and in particular to a novel GNSS-IR altitude angle deviation correction method and system. Background Art

[0002] With the widespread application of the Global Navigation Satellite System (GNSS), its importance in the fields of marine remote sensing, positioning and navigation has become increasingly prominent. Among them, GNSS interferometric reflection (GNSS-IR) technology, as an emerging technology, can accurately measure surface environmental parameters (such as sea level) by analyzing the characteristics of GNSS signals after being reflected from the surface. However, in actual applications, due to the influence of the ionosphere, GNSS signals will be refracted during propagation, resulting in deviations in the altitude angle, which in turn affects the accurate calculation of the sea level.

[0003] The ionosphere is a region of the atmosphere filled with free electrons and ions. These charged particles will refract the electromagnetic waves (including GNSS signals) passing through. This refraction effect will not only cause the signal propagation path to deviate, but also cause changes in the signal propagation speed, thus significantly affecting the positioning accuracy of GNSS and sea level measurement. The impact of the ionosphere is particularly significant in high latitudes and during the peak of solar activity. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a novel GNSS-IR altitude angle deviation correction method and system, which improves the accuracy and reliability of sea surface height measurement.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] In a first aspect, a novel GNSS-IR altitude angle deviation correction method and system includes:

[0007] A new method of correcting the elevation angle deviation based on the electron density is established through the refraction angle relationship.

[0008] Generate SNR file, which contains pseudo-random noise code, azimuth, altitude, and S1C observation data of about 15,000 epochs per day;

[0009] The satellite zenith distance and position of the ionospheric puncture point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model;

[0010] The electron density and satellite zenith distance are used as input parameters to input into a new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

[0011] Furthermore, a new method for correcting the elevation angle deviation based on the electron density is established through the refraction angle relationship, including:

[0012] Determine the relationship between the refraction angle and the altitude angle deviation, specifically including: based on the propagation theory of electromagnetic waves in the atmosphere, analyze the mathematical relationship between the refraction angle and the altitude angle of the GNSS signal, introduce the electron density as a key parameter into the altitude angle deviation correction model, and establish the quantitative relationship between the electron density and the refraction angle;

[0013] Acquire GNSS observation data containing pseudo-random noise code, azimuth and altitude information;

[0014] Using the Nequick-G model and the puncture point information, the electron density distribution in the ionosphere is calculated;

[0015] Based on the relationship between the refraction angle and the altitude angle and the influence of the electron density, an altitude angle deviation correction model is constructed so that the correction model can output a corrected altitude angle value according to the input electron density and observation data; the calculated electron density data and GNSS observation data are input into the correction model, and the altitude angle value corrected by the refraction angle relationship is obtained through correction model calculation;

[0016] Use known high-precision sea surface height data to verify the corrected altitude angle, and analyze the altitude angle deviation before and after correction to obtain verification results;

[0017] According to the verification results, the parameters in the revised model are adjusted and optimized.

[0018] Furthermore, based on the propagation theory of electromagnetic waves in the atmosphere, the mathematical relationship between the refraction angle and the GNSS signal altitude angle is analyzed, and the electron density is introduced as a key parameter into the altitude angle deviation correction model to establish the quantitative relationship between the electron density and the refraction angle, including:

[0019] Obtain raw observation data from GNSS receivers, including pseudo-random noise code, azimuth, and uncorrected altitude; obtain ionospheric electron density data;

[0020] According to Snell's law, the basic relationship between the refraction angle and the altitude angle is established; according to the basic relationship between the refraction angle and the altitude angle, the mathematical conversion relationship between the refraction angle and the altitude angle is established, that is, the altitude angle is the complementary angle of the refraction angle;

[0021] Based on the electromagnetic wave propagation theory, simulate the refraction of electromagnetic waves under different electron densities; according to the physical characteristics of the ionosphere, establish the mathematical relationship between electron density and refractive index, and calculate the corresponding refractive index based on the mathematical relationship between electron density and refractive index;

[0022] Real-time observation data and electron density data are continuously obtained from GNSS receivers and ionosphere models, and the real-time data are input into a verified and optimized altitude angle deviation correction model so that the deviation correction model can automatically calculate the corrected altitude angle.

[0023] Furthermore, the electron density distribution in the ionosphere is calculated using the Nequick-G model and the puncture point information, including:

[0024] Set the input parameters of the Nequick-G model, including time, geographic location, and solar activity index;

[0025] Using the GNSS receiver's observation data and satellite orbit information, determine the signal propagation path from the satellite to the receiver; the puncture point is the point where the GNSS signal path intersects the ionosphere; through geometric calculations, determine the position and height of the intersection of the signal path and the ionosphere;

[0026] Using the configured Nequick-G model and puncture point information as input, the Nequick-G model will calculate the electron density value at the puncture point based on the input parameters and internal algorithms;

[0027] The calculated electron density values ​​are organized into a data set, and an electron density distribution map is drawn based on the data set.

[0028] Furthermore, the satellite zenith distance and position of the ionospheric piercing point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model, including:

[0029] Extract eight parameters of the Krobucher model from the GNSS broadcast ephemeris; Calculate the vertical component of the ionospheric delay based on the user position and satellite position, as well as the Krobucher model parameters in the broadcast ephemeris;

[0030] The user's position is determined using the observation data of the GNSS receiver, and the position of the satellite is determined based on the satellite's orbital information; the satellite zenith distance is the angle between the vector from the user's position to the satellite's position and the zenith direction at the user's position, and the puncture point is the point where the GNSS signal intersects the ionosphere when it propagates from the satellite to the user;

[0031] The longitude, latitude and altitude of the puncture point are iteratively calculated using the Krobucher model and the satellite zenith distance, combined with the earth shape and ionospheric altitude information;

[0032] The puncture point position and time input data are passed to the Nequick-G model, and the Nequick-G model calculation is performed to obtain the electron density value at the puncture point; the electron density value is obtained from the Nequick-G model.

[0033] Furthermore, the electron density and the satellite zenith distance are used as input parameters to input into a new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle, including:

[0034] Obtain the electron density value at the ionospheric puncture point; Calculate the satellite zenith distance from the observation data of the GNSS receiver;

[0035] The electron density and the satellite zenith distance are passed as input parameters to the altitude angle deviation correction model, and the deviation correction model is executed to obtain the altitude angle deviation caused by the influence of the ionosphere;

[0036] The original elevation angle of the satellite signal is obtained from the observation data of the GNSS receiver, and the calculated angle error is subtracted from the original elevation angle to obtain the corrected elevation angle;

[0037] The corrected altitude angle is passed to the sea surface height calculation model, the sea surface height calculation model is executed, and the estimated value of the sea surface height is obtained by combining the receiver position, satellite position and signal propagation time.

[0038] Second, a new GNSS-IR altitude angle deviation correction system, including:

[0039] Establish a module for establishing a new altitude angle deviation correction method based on electron density through refraction angle relationship;

[0040] The generation module is used to generate SNR files. The SNR files contain pseudo-random noise codes, azimuth, altitude, and S1C observation data for about 15,000 epochs per day.

[0041] A calculation module is used to obtain the satellite zenith distance and position of the ionospheric puncture point using the Krobucher model, and input the Nequick-G model to calculate the electron density;

[0042] The correction module is used to input electron density and satellite zenith distance as input parameters into a new altitude angle deviation correction method to obtain angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

[0043] Thirdly, a new GNSS-IR altitude angle deviation correction device includes:

[0044] one or more processors;

[0045] The storage system is used to store one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the method described.

[0046] In a fourth aspect, a computer-readable storage medium stores a program, and when the program is executed by a processor, the method described is implemented.

[0047] The above solution of the present invention includes at least the following beneficial effects:

[0048] A new altitude angle deviation correction method based on electron density is established through the refraction angle relationship, which can more accurately calculate and correct the altitude angle deviation caused by ionospheric refraction. Experimental data show that the sea surface height measurement accuracy corresponding to the altitude angle corrected by this method has been significantly improved, which is of great significance for applications such as ocean mapping and sea surface height monitoring.

[0049] The present invention provides a rich data source for altitude deviation correction by generating an SNR file containing a large amount of epoch observation data. These observation data include pseudo-random noise code, azimuth, altitude, etc., which can fully reflect the various changes of GNSS signals during the propagation process, thereby improving the reliability and stability of the correction results.

[0050] The present invention combines the Krobucher model and the Nequick-G model to achieve accurate calculation of the electron density at the ionospheric puncture point. Using the electron density and the satellite zenith distance as input parameters makes the correction process of the altitude angle deviation more scientific and reasonable, and easy to realize automatic processing, greatly improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a flow chart of a novel GNSS-IR altitude angle deviation correction method provided by an embodiment of the present invention.

[0052] Figure 2 It is a schematic diagram of a novel GNSS-IR altitude angle deviation correction system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0054] like Figure 1 As shown, an embodiment of the present invention proposes a novel GNSS-IR altitude angle deviation correction method, the method comprising the following steps:

[0055] A new method of correcting the elevation angle deviation based on the electron density is established through the refraction angle relationship.

[0056] Generate SNR file, which contains pseudo-random noise code, azimuth, altitude, and S1C observation data of about 15,000 epochs per day;

[0057] The satellite zenith distance and position of the ionospheric puncture point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model;

[0058] The electron density and satellite zenith distance are used as input parameters to input into a new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

[0059] In an embodiment of the present invention, a new method for correcting the elevation angle deviation with electron density as a reference is established through the refraction angle relationship, which can more accurately calculate and correct the elevation angle deviation caused by ionospheric refraction. Experimental data show that the sea level measurement accuracy corresponding to the elevation angle corrected by this method has been significantly improved, which is of great significance for applications such as marine mapping and sea level monitoring. The present invention provides a rich data source for the correction of elevation angle deviation by generating an SNR file containing a large number of epoch observation data. These observation data include pseudo-random noise codes, azimuths, elevation angles, etc., which can fully reflect the various changes of GNSS signals during the propagation process, thereby improving the reliability and stability of the correction results. The present invention combines the Krobucher model and the Nequick-G model to achieve accurate calculation of the electron density of the ionospheric puncture point. Using electron density and satellite zenith distance as input parameters makes the correction process of elevation angle deviation more scientific and reasonable, and easy to realize automatic processing, greatly improving work efficiency.

[0060] Furthermore, a new method for correcting the elevation angle deviation based on the electron density is established through the refraction angle relationship, including:

[0061] Determine the relationship between the refraction angle and the altitude angle deviation, specifically including: based on the propagation theory of electromagnetic waves in the atmosphere, analyze the mathematical relationship between the refraction angle and the altitude angle of the GNSS signal, introduce the electron density as a key parameter into the altitude angle deviation correction model, and establish the quantitative relationship between the electron density and the refraction angle;

[0062] Acquire GNSS observation data containing pseudo-random noise code, azimuth and altitude information;

[0063] Using the Nequick-G model and the puncture point information, the electron density distribution in the ionosphere is calculated;

[0064] Based on the relationship between the refraction angle and the altitude angle and the influence of the electron density, an altitude angle deviation correction model is constructed so that the correction model outputs the corrected altitude angle value according to the input electron density and observation data; the calculated electron density data and GNSS observation data are input into the correction model, and the altitude angle value corrected by the refraction angle relationship is obtained through the correction model operation, which specifically includes:

[0065] According to the propagation theory of electromagnetic waves in the atmosphere, the mathematical relationship between the refraction angle and the GNSS signal altitude angle is derived. The electron density is taken as the key factor affecting refraction. It is assumed that the GNSS signal is refracted during propagation and the incident angle is θ. i , the refraction angle is θ r According to the law of refraction (Snell's law), the relationship between the angle of refraction and the angle of incidence is: sin(θ i )=nsin(θ r );

[0066] Using the ionosphere model (such as the Nequick-G model), a correction model that can reflect the effect of electron density on the altitude angle deviation is constructed; in the model, it is ensured that the electron density data and GNSS observation data (including pseudo-random noise code, azimuth, original altitude angle, etc.) can be input. The core of the correction model is to correct the relationship between the altitude angle H and the refraction angle θr according to the electron density. The correction model can be expressed as:

[0067]

[0068] Where ΔH is the deviation of the altitude angle (i.e., the change caused by the refraction effect); H0 is the original altitude angle; H r is the elevation angle after refraction correction; ΔN(e) is the change in electron density on the signal propagation path; N(e) is the electron density.

[0069] Acquire GNSS observation data, including pseudo-random noise code, azimuth and original altitude information, calculate the electron density distribution data in the ionosphere using the Nequick-G model and puncture point information, organize and preprocess the calculated electron density data and GNSS observation data in the format required by the correction model, and input the organized data into the correction model as the input condition for model operation; in the correction model, perform correction calculation of altitude deviation based on the input electron density data and observation data using the previously established mathematical relationship, solve the corrected altitude value through iteration or analytical method to ensure the accuracy and stability of the calculation results, output the altitude value calculated by the correction model after correction by the refraction angle relationship to the specified file or data structure, and visualize the comparison of altitude angles before and after correction to further analyze and verify the correction effect.

[0070] Using known high-precision sea surface height data, the corrected altitude angle is verified, and the altitude angle deviation before and after correction is analyzed to obtain the verification results; according to the verification results, the parameters in the correction model are adjusted and optimized, including:

[0071] Collect high-precision sea surface height data corresponding to GNSS observation data, which can be obtained through other independent measurement methods (such as tide gauges, satellite altimetry missions, etc.); convert the corrected altitude angle data into corresponding sea surface height values, which involves calculating using the GNSS signal reflection principle; compare these calculated sea surface height values ​​with the known high-precision sea surface height data, and calculate the difference between them; perform statistical processing on the results of comparative analysis, such as calculating statistical indicators such as mean deviation, standard deviation, and root mean square error, to evaluate the degree of agreement between the sea surface height corresponding to the corrected altitude angle and the true sea surface height, so as to verify the effectiveness of the correction method; present the results of comparative analysis in the form of graphs, such as scatter plots, line graphs, error distribution graphs, etc., which helps to intuitively understand the altitude angle deviation before and after correction and the spatial and temporal distribution of the correction effect.

[0072] Analyze the influence of each parameter in the correction model on the correction result and determine the key parameters. This can be done by changing the parameter value and observing the change of the correction result. According to the statistical evaluation of the verification results, formulate the strategy and goal of parameter adjustment. For example, if the verification results show that the corrected elevation angle is overall low, then it may be necessary to adjust the parameters related to the refraction angle or electron density in the model; use the optimization algorithm (such as the least squares method) to adjust the key parameters, use the statistical indicators of the verification results as the optimization objective function, find the optimal parameter combination through iterative calculation, re-run the correction model with the optimized parameters, obtain the new corrected elevation angle data, and use the known high-precision sea surface height data to verify the new correction results again and evaluate the optimization effect. If the optimization effect is not significant or does not achieve the expected goal, repeat the above steps of parameter sensitivity analysis, strategy formulation, optimization implementation and effect verification, and gradually approach the optimal correction model parameter configuration through multiple iterations and adjustments.

[0073] In an embodiment of the present invention, the method establishes the precise mathematical relationship between the refraction angle and the GNSS signal elevation angle by deeply analyzing the propagation theory of electromagnetic waves in the atmosphere, and introduces the electron density as a key parameter into the correction model. This processing method can more accurately reflect the influence of the ionosphere on the propagation path of the GNSS signal, thereby significantly improving the correction accuracy of the elevation angle deviation. Since the method takes into account the quantitative relationship between the electron density and the refraction angle, the correction model can be adaptively adjusted according to the changes in the electron density under different ionospheric conditions. This characteristic enables the method to maintain a high correction effect in various environments, greatly enhancing the applicability of the model. By integrating the Nequick-G model and the puncture point information to calculate the electron density distribution in the ionosphere, and combining the GNSS observation data to correct the elevation angle deviation, the method realizes an efficient and automated data processing process. This process not only improves work efficiency, but also reduces the errors introduced by human operation, and further ensures the accuracy of the correction results. The method uses known high-precision sea surface height data to verify the corrected elevation angle, and adjusts and optimizes the parameters in the correction model according to the verification results. This verification and feedback mechanism can ensure the continuous improvement and optimization of the correction method in practical applications, and continuously enhance its performance.

[0074] Furthermore, based on the propagation theory of electromagnetic waves in the atmosphere, the mathematical relationship between the refraction angle and the GNSS signal altitude angle is analyzed, and the electron density is introduced as a key parameter into the altitude angle deviation correction model to establish the quantitative relationship between the electron density and the refraction angle, including:

[0075] Obtain the original observation data from the GNSS receiver, including pseudo-random noise code, azimuth, and uncorrected altitude angle; obtain the electron density data of the ionosphere; establish the basic relationship between the refraction angle and the altitude angle according to Snell's law; and establish the mathematical conversion relationship between the refraction angle and the altitude angle according to the basic relationship between the refraction angle and the altitude angle, that is, the altitude angle is the complementary angle of the refraction angle, including:

[0076] Establish a communication connection with the GNSS receiver and use a communication protocol (such as NMEA, RTCM, etc.) to establish a connection with the GNSS receiver; receive raw observation data containing pseudo-random noise code (PRN), azimuth, uncorrected elevation angle, etc. from the GNSS receiver, use the corresponding data parsing algorithm to extract the required observation values, store the parsed observation data in a local database or data structure, implement data quality checks, and remove abnormal or invalid data; select a suitable ionospheric model (such as IRI model, Nequick-G model, etc.) according to application requirements and ionospheric conditions; calculate the geographical location and time of the puncture point (IPP) according to the propagation path of the GNSS signal, pass the puncture point information as input parameters to the ionospheric model, use the ionospheric model to calculate the electron density value at the puncture point, and ensure that the model parameters are set correctly to obtain accurate electron density data; store the calculated electron density data in a local database or data structure, corresponding to the observation data, for subsequent processing and analysis.

[0077] According to Snell's Law, the refraction phenomenon of electromagnetic waves in the atmosphere is analyzed, and the basic relationship between the refraction angle (Refraction Angle) and the incident angle (Incident Angle, that is, the uncorrected altitude angle) is established. Based on the basic relationship of Snell's Law, the mathematical conversion relationship between the refraction angle and the altitude angle is derived. The altitude angle is the complementary angle of the refraction angle, that is, the sum of the two is 90 degrees.

[0078] Based on the electromagnetic wave propagation theory, the refraction of electromagnetic waves under different electron densities is simulated; according to the physical characteristics of the ionosphere, the mathematical relationship between the electron density and the refractive index is established, and the corresponding refractive index is calculated according to the mathematical relationship between the electron density and the refractive index, including:

[0079] Use electromagnetic wave propagation simulation software or a custom simulation environment to set up scenarios with different electron densities, consider the multi-layer structure of the Earth's atmosphere, especially the impact of the ionosphere on electromagnetic waves; define parameters such as the frequency and emission angle (i.e., uncorrected altitude angle) of electromagnetic waves, which should match the characteristics of actual GNSS signals. In different electron density scenarios, simulate the propagation and refraction process of electromagnetic waves, record the changes in the refraction angle of electromagnetic waves under different electron densities, analyze the simulation data, observe the impact of changes in electron density on the refraction angle of electromagnetic waves, and establish a trend graph between electron density and refraction angle. Understand the composition, structure, and physical properties of the ionosphere, especially the relationship between electron density and refractive index, refer to relevant literature and research materials, and obtain a mathematical model of electron density and refractive index in the ionosphere; based on the physical properties of the ionosphere and existing research, determine the mathematical relationship between electron density and refractive index, which is:

[0080]

[0081] Among them, N(e) is the electron density (unit: number of electrons / cubic meter); f is the electromagnetic wave frequency (unit: Hertz); and n is the refractive index.

[0082] Continuously obtain real-time observation data and electron density data from GNSS receivers and ionosphere models, and input the real-time data into the verified and optimized altitude angle deviation correction model so that the deviation correction model can automatically calculate the corrected altitude angle, including:

[0083] Establish continuous data communication with the GNSS receiver to receive observation data in real time, including uncorrected altitude angle. At the same time, obtain real-time electron density data from the ionosphere model; perform necessary preprocessing on the received observation data and electron density data, such as format conversion, outlier removal, etc.; deploy the verified and optimized altitude angle deviation correction model into the real-time processing environment, which can receive real-time observation data and electron density data as input; input the preprocessed real-time data into the altitude angle deviation correction model, and the model automatically calculates the corrected altitude angle based on the input electron density data and observation data, using the previously established mathematical relationship between electron density and refractive index, and outputs the corrected altitude angle data to the specified interface or storage medium, and can choose to store the correction results together with the original observation data for subsequent analysis and comparison.

[0084] In an embodiment of the present invention, by establishing a quantitative relationship between electron density and refraction angle, and correcting the altitude angle accordingly, the positioning error caused by atmospheric refraction can be significantly reduced. Since the influence of ionospheric electron density on electromagnetic wave refraction is taken into account, the model can provide more accurate correction effects under different atmospheric conditions. This means that whether it is day or night, whether the ionospheric activity is strong or calm, the model can maintain a high correction accuracy. By continuously acquiring real-time observation data and electron density data from GNSS receivers and ionospheric models, the model can correct the altitude angle in real time. The introduction of electron density as a key parameter makes the model more robust in the face of complex ionospheric changes. Even in the case of abnormal fluctuations in the ionosphere, the model can adapt to these changes by adjusting parameters, thereby maintaining the stability of the correction effect.

[0085] Furthermore, the electron density distribution in the ionosphere is calculated using the Nequick-G model and the puncture point information, including:

[0086] Set the input parameters of the Nequick-G model, including time, geographic location, and solar activity index;

[0087] Using the GNSS receiver's observation data and satellite orbit information, determine the signal propagation path from the satellite to the receiver; the puncture point is the point where the GNSS signal path intersects the ionosphere; through geometric calculations, determine the position and height of the intersection of the signal path and the ionosphere;

[0088] Using the configured Nequick-G model and puncture point information as input, the Nequick-G model will calculate the electron density value at the puncture point based on the input parameters and internal algorithms;

[0089] The calculated electron density values ​​are organized into a data set, and an electron density distribution map is drawn based on the data set.

[0090] In an embodiment of the present invention, it is ensured that the model can run accurately under specific time and space conditions, and accurate background information is provided for subsequent electron density calculations. Accurately grasping the signal propagation path helps to accurately locate the puncture point, thereby improving the accuracy of the electron density calculation. The accurate determination of the puncture point is the key to the electron density calculation, and the accuracy of this step directly affects the reliability of the final electron density distribution. With the help of a professional ionospheric model, the electron density can be calculated scientifically and accurately, providing a solid foundation for subsequent electron density distribution analysis. The intuitive display of the electron density distribution in the ionosphere in a visual way helps scientific researchers to better understand the state of the ionosphere and provide strong support for research and application in related fields. At the same time, it also provides a data basis for further analysis and prediction of ionospheric changes.

[0091] The specific implementation process of each of the above steps is as follows:

[0092] Set the input parameters of the Nequick-G model, including:

[0093] Get the current time information, including year, month, day, hour, minute, and second; determine the geographic location of the receiver, usually expressed by longitude and latitude, which can be obtained from a GNSS receiver or other positioning equipment; get the solar activity index, such as F10.7 solar radio flux, which is an important parameter to characterize the strength of solar activity and can be obtained through professional space environment monitoring agencies or databases. Configure the above parameters according to the input format requirements of the Nequick-G model and save them as files or data structures that can be read by the model.

[0094] Determine the GNSS signal propagation path and puncture points, including:

[0095] The original observation data is obtained from the GNSS receiver, including the satellite's pseudorange, carrier phase and other information, combined with the satellite's orbital information, usually obtained through satellite ephemeris files (such as SP3 files), and the precise position of the satellite at the time of signal transmission is calculated. The position of the receiver and the position of the satellite are used to determine the signal propagation path through geometric algorithms (such as the least squares method), that is, the straight or curved trajectory of the signal from the satellite to the receiver. The determination of the puncture point needs to take into account the shape and thickness of the ionosphere. Usually, a simplified ionosphere model (such as a single-layer model) can be used to approximate the position and height of the puncture point. The intersection of the signal path and the ionosphere model is found through iterative calculation or analytical methods, which is the puncture point.

[0096] The electron density values ​​are calculated using the Nequick-G model, including:

[0097] Load the configured input parameter file or data structure into the Nequick-G model, and use the calculated puncture point information (position and height) as the model input; run the Nequick-G model, and the model will calculate based on the input parameters and internal algorithms (such as ionospheric physics model, etc.), and the model outputs the electron density value at the puncture point, usually in electrons / cubic meter (el / m 3 ) as the unit, and save the calculated electron density value for subsequent analysis and processing.

[0098] The calculated electron density values ​​at each puncture point are organized into a data set, which can be organized by time, geographic location or other dimensions. The data set is loaded using data analysis software or programming languages ​​(such as the matplotlib library in Python). According to the characteristics of the data set, appropriate chart types are selected, such as scatter plots, contour plots, or three-dimensional surface plots, to visually display the distribution of electron density at different positions and heights. Elements such as the chart title, axis labels, and legends are configured to ensure that the chart is clear and easy to read. The drawn electron density distribution map is saved and exported for subsequent analysis, reporting, or presentation.

[0099] Furthermore, the satellite zenith distance and position of the ionospheric piercing point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model, including:

[0100] Extract eight parameters of the Krobucher model from the GNSS broadcast ephemeris; Calculate the vertical component of the ionospheric delay based on the user position and satellite position, as well as the Krobucher model parameters in the broadcast ephemeris;

[0101] The user's position is determined using the observation data of the GNSS receiver, and the position of the satellite is determined based on the satellite's orbital information; the satellite zenith distance is the angle between the vector from the user's position to the satellite's position and the zenith direction at the user's position, and the puncture point is the point where the GNSS signal intersects the ionosphere when it propagates from the satellite to the user;

[0102] The longitude, latitude and altitude of the puncture point are iteratively calculated using the Krobucher model and the satellite zenith distance, combined with the earth shape and ionospheric altitude information;

[0103] The puncture point position and time input data are passed to the Nequick-G model, and the Nequick-G model calculation is performed to obtain the electron density value at the puncture point; the electron density value is obtained from the Nequick-G model.

[0104] In an embodiment of the present invention, the Krobucher model can more accurately describe the delay effect of the ionosphere on the GNSS signal, especially in the calculation of the vertical component. The puncture point information obtained by this model is more accurate, thereby improving the correction accuracy of the ionospheric delay, which helps to improve the accuracy of GNSS positioning. Combining the Krobucher model, the satellite zenith distance, the earth shape and the ionosphere height information, a more accurate puncture point position (longitude, latitude and altitude) can be iteratively calculated. This optimized positioning calculation method not only improves the positioning accuracy of the puncture point, but also provides more reliable input data for subsequent electron density calculations. By inputting the precise puncture point position and time information into the Nequick-G model, a more accurate electron density calculation can be performed. The Nequick-G model itself has a high calculation accuracy, and the accurate input data further guarantees the reliability of its output results. Therefore, this scheme can significantly enhance the accuracy of electron density calculation. The accurate electron density value obtained by the above steps can be applied to various scenarios of GNSS, such as positioning, navigation, timing, etc. Accurate electron density information helps reduce the impact of the ionosphere on GNSS signals, thereby improving the overall performance of GNSS applications.

[0105] The specific implementation process of each of the above steps is as follows:

[0106] The eight parameters of the Krobucher model are extracted from the GNSS broadcast ephemeris. The specific implementation process is as follows:

[0107] Read data from GNSS broadcast ephemeris files, which are usually provided by satellite navigation systems and contain satellite orbit and clock information; parse the broadcast ephemeris to find the parameter segments related to the Krobucher model, which usually include coefficients describing the influence of the ionosphere, and extract the eight key parameters of the Krobucher model, which are used for subsequent ionospheric delay calculations.

[0108] The specific implementation process of calculating the vertical component of ionospheric delay is as follows:

[0109] According to the position of the user's receiver and the position of the satellite, the geometric relationship between the two is calculated. Using the Krobucher model formula, the eight extracted parameters and the geometric relationship between the user and the satellite are substituted to calculate the delay caused by the ionosphere to the signal. The vertical component is separated from the total delay, which is the main factor affecting positioning accuracy. The calculated vertical component of ionospheric delay is recorded and saved.

[0110] Using the observation data received by the GNSS receiver, the user's precise position on the earth is determined through pseudorange measurement and other methods; based on the satellite's orbital information, the satellite's position at a specific time is determined by parsing the satellite ephemeris file or using other orbital prediction models to ensure the accuracy of the user and satellite positions, as this is the basis for the subsequent calculation of the puncture point and zenith distance.

[0111] The specific process of calculating the satellite zenith distance and determining the puncture point is as follows:

[0112] Based on the user position and satellite position, the vector between the two is calculated to determine the zenith direction at the user position, that is, the direction perpendicular to the ground, and the satellite zenith distance, that is, the angle between the vector from the user to the satellite and the user zenith direction, is calculated. Combined with the shape of the earth, ionospheric height information and the Krobucher model, the longitude, latitude and altitude of the puncture point where the GNSS signal intersects the ionosphere are determined through an iterative calculation method.

[0113] The specific implementation process of calculating the electron density value using the Nequick-G model is as follows:

[0114] Convert the longitude, latitude, and altitude information of the puncture point into a format acceptable to the Nequick-G model. This usually involves converting geographic coordinates into the coordinate system required by the model (such as the Earth-centered Earth-fixed coordinate system); obtain the time information corresponding to the puncture point, including year, month, day, hour, minute, and second, and ensure that the time format matches the input requirements of the Nequick-G model; create an input file containing the puncture point location and time information according to the input specifications of the Nequick-G model. This file is a text file with a specific structure and format to ensure that the data in the input file is accurate and arranged in the order and format required by the model.

[0115] Open the command line interface or the corresponding software environment, prepare to call the Nequick-G model, enter the call command, specify the path and name of the input file, and other possible operating parameters (such as the output file path, model configuration options, etc.); run the Nequick-G model, and the model will read the puncture point location and time information in the input file; the model will start calculating the electron density value at the puncture point based on this information, combined with its built-in ionospheric physics model and mathematical algorithm; once the Nequick-G model completes the calculation, it will generate an output file containing the electron density value, open the output file, check the data in it to ensure that the calculation is successful, and extract the required electron density value.

[0116] The electron density values ​​obtained from the Nequick-G model are saved in an appropriate data storage system for subsequent analysis and application. The electron density values ​​can be further processed using data analysis tools or programming languages, such as drawing distribution maps, calculating statistical indicators, etc., to better understand the state and changes of the ionosphere.

[0117] Furthermore, the electron density and the satellite zenith distance are used as input parameters to input into a new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle, including:

[0118] Obtain the electron density value at the ionospheric puncture point; Calculate the satellite zenith distance from the observation data of the GNSS receiver;

[0119] The electron density and the satellite zenith distance are passed as input parameters to the altitude angle deviation correction model, and the deviation correction model is executed to obtain the altitude angle deviation caused by the influence of the ionosphere;

[0120] The original elevation angle of the satellite signal is obtained from the observation data of the GNSS receiver, and the calculated angle error is subtracted from the original elevation angle to obtain the corrected elevation angle;

[0121] The corrected altitude angle is passed to the sea surface height calculation model, the sea surface height calculation model is executed, and the estimated value of the sea surface height is obtained by combining the receiver position, satellite position and signal propagation time.

[0122] In an embodiment of the present invention, by introducing electron density and satellite zenith distance as input parameters, the new altitude angle deviation correction method can more accurately estimate and correct the altitude angle deviation caused by the influence of the ionosphere. This significantly improves the measurement accuracy of the altitude angle of satellite signals in the GNSS receiver. Using the corrected altitude angle for sea surface height calculation can greatly reduce the error caused by ionospheric interference, thereby obtaining a more reliable and accurate sea surface height estimate. By reducing the impact of the ionosphere on altitude angle measurement, the scheme improves the robustness and reliability of GNSS applications in various complex environments. Whether in active periods of the ionosphere or under other challenging conditions, high positioning accuracy and stability can be maintained. With the improvement of altitude angle measurement accuracy and the optimization of sea surface height estimation, the application field of GNSS systems will be further expanded. For example, in marine resource exploration, ship navigation, remote sensing and other aspects, this technology can be used to improve the effectiveness of existing methods.

[0123] The specific implementation process of each of the above steps is as follows:

[0124] Use the ionospheric piercing point location information previously calculated by the Krobucher model and the Nequick-G model to ensure that these piercing point location information are accurate and up-to-date, because the electron density of the ionosphere varies with time and space; directly obtain or read previously saved electron density values ​​from the output of the Nequick-G model, which correspond to specific piercing point locations and times.

[0125] Obtain the original observation data from the GNSS receiver, which usually includes information such as the satellite's pseudorange, carrier phase, and Doppler frequency shift. Analyze the observation data, extract the direction vector from the user's position to each visible satellite, and calculate the zenith direction vector at the user's position, that is, the upward direction perpendicular to the ground. For each satellite, calculate the angle between its direction vector and the user's zenith direction vector. This angle is the satellite zenith distance.

[0126] Prepare the altitude deviation correction model and ensure that the model has been verified and is applicable to the current environment and conditions; pass the obtained electron density value and the calculated satellite zenith distance as input parameters to the model; run the model and calculate the altitude deviation caused by the influence of the ionosphere according to the internal algorithms and formulas, and check the output of the model to ensure that the obtained altitude deviation value is reasonable and accurate.

[0127] The original altitude angle information of the satellite signal is obtained from the observation data of the GNSS receiver; the calculated altitude angle deviation value is subtracted from the original altitude angle to perform deviation correction to ensure that the corrected altitude angle is within a reasonable range and closer to the true value, and the corrected altitude angle data is saved for use in subsequent steps.

[0128] Prepare the sea surface height calculation model to ensure that the model is suitable for the current application scenario and accuracy requirements. Pass the corrected altitude angle data as input parameters to the sea surface height calculation model. At the same time, pass the GNSS receiver's position, satellite's position, and signal propagation time as input parameters to the model. Run the model and calculate the estimated value of the sea surface height based on the internal algorithm and formula combined with all the input parameters. Check the output of the model to ensure that the estimated value of the sea surface height is accurate and reliable. If necessary, the model can be tuned to improve the calculation accuracy.

[0129] Second, a new GNSS-IR altitude angle deviation correction system, including:

[0130] Establish a module for establishing a new altitude angle deviation correction method based on electron density through refraction angle relationship;

[0131] The generation module is used to generate SNR files. The SNR files contain pseudo-random noise codes, azimuth, altitude, and S1C observation data for about 15,000 epochs per day.

[0132] A calculation module is used to obtain the satellite zenith distance and position of the ionospheric puncture point using the Krobucher model, and input the Nequick-G model to calculate the electron density;

[0133] The correction module is used to input electron density and satellite zenith distance as input parameters into a new altitude angle deviation correction method to obtain angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

[0134] The embodiment of the present invention also provides a computer-readable storage medium storing instructions, which, when executed on a computer, enable the computer to execute the method described above. All implementations in the above method embodiment are applicable to this embodiment and can achieve the same technical effect.

[0135] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A novel GNSS-IR altitude angle deviation correction method, characterized in that: The method comprises: A new method of correcting the elevation angle deviation based on the electron density is established through the refraction angle relationship. Generate SNR file, which contains pseudo-random noise code, azimuth, altitude, and S1C observation data of about 15,000 epochs per day; The satellite zenith distance and position of the ionospheric puncture point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model; The electron density and satellite zenith distance are used as input parameters to input into a new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

2. The novel GNSS-IR altitude angle deviation correction method according to claim 1 is characterized in that: A new method for correcting the height angle deviation based on the electron density is established through the refraction angle relationship, including: Determine the relationship between the refraction angle and the altitude angle deviation, specifically including: based on the propagation theory of electromagnetic waves in the atmosphere, analyze the mathematical relationship between the refraction angle and the altitude angle of the GNSS signal, introduce the electron density as a key parameter into the altitude angle deviation correction model, and establish the quantitative relationship between the electron density and the refraction angle; Acquire GNSS observation data containing pseudo-random noise code, azimuth and altitude information; Using the Nequick-G model and the puncture point information, the electron density distribution in the ionosphere is calculated; Based on the relationship between the refraction angle and the altitude angle and the influence of the electron density, an altitude angle deviation correction model is constructed so that the correction model can output a corrected altitude angle value according to the input electron density and observation data; the calculated electron density data and GNSS observation data are input into the correction model, and the altitude angle value corrected by the refraction angle relationship is obtained through correction model calculation; Use known high-precision sea surface height data to verify the corrected altitude angle, and analyze the altitude angle deviation before and after correction to obtain verification results; According to the verification results, the parameters in the revised model are adjusted and optimized.

3. The novel GNSS-IR altitude angle deviation correction method according to claim 2 is characterized in that: Based on the propagation theory of electromagnetic waves in the atmosphere, the mathematical relationship between the refraction angle and the GNSS signal altitude angle is analyzed, and the electron density is introduced as a key parameter into the altitude angle deviation correction model to establish the quantitative relationship between the electron density and the refraction angle, including: Obtain raw observation data from GNSS receivers, including pseudo-random noise code, azimuth, and uncorrected altitude; obtain ionospheric electron density data; According to Snell's law, the basic relationship between the refraction angle and the altitude angle is established; according to the basic relationship between the refraction angle and the altitude angle, the mathematical conversion relationship between the refraction angle and the altitude angle is established, that is, the altitude angle is the complementary angle of the refraction angle; Based on the electromagnetic wave propagation theory, simulate the refraction of electromagnetic waves under different electron densities; according to the physical characteristics of the ionosphere, establish the mathematical relationship between electron density and refractive index, and calculate the corresponding refractive index based on the mathematical relationship between electron density and refractive index; Real-time observation data and electron density data are continuously obtained from GNSS receivers and ionosphere models, and the real-time data are input into a verified and optimized altitude angle deviation correction model so that the deviation correction model can automatically calculate the corrected altitude angle.

4. The novel GNSS-IR altitude angle deviation correction method according to claim 3 is characterized in that: Using the Nequick-G model and puncture point information, the electron density distribution in the ionosphere is calculated, including: Set the input parameters of the Nequick-G model, including time, geographic location, and solar activity index; Using the GNSS receiver's observation data and satellite orbit information, determine the signal propagation path from the satellite to the receiver; the puncture point is the point where the GNSS signal path intersects the ionosphere; through geometric calculations, determine the position and height of the intersection of the signal path and the ionosphere; Using the configured Nequick-G model and puncture point information as input, the Nequick-G model will calculate the electron density value at the puncture point based on the input parameters and internal algorithms; The calculated electron density values ​​are organized into a data set, and an electron density distribution map is drawn based on the data set.

5. The novel GNSS-IR altitude angle deviation correction method according to claim 4 is characterized in that: The satellite zenith distance and position of the ionospheric puncture point are obtained by using the Krobucher model, and the electron density is calculated by inputting the Nequick-G model, including: Extract eight parameters of the Krobucher model from the GNSS broadcast ephemeris; Calculate the vertical component of the ionospheric delay based on the user position and satellite position, as well as the Krobucher model parameters in the broadcast ephemeris; The user's position is determined using the observation data of the GNSS receiver, and the position of the satellite is determined based on the satellite's orbital information; the satellite zenith distance is the angle between the vector from the user's position to the satellite's position and the zenith direction at the user's position, and the puncture point is the point where the GNSS signal intersects the ionosphere when it propagates from the satellite to the user; The longitude, latitude and altitude of the puncture point are iteratively calculated using the Krobucher model and the satellite zenith distance, combined with the earth shape and ionospheric altitude information; The puncture point position and time input data are passed to the Nequick-G model, and the Nequick-G model calculation is performed to obtain the electron density value at the puncture point; the electron density value is obtained from the Nequick-G model.

6. The novel GNSS-IR altitude angle deviation correction method according to claim 5 is characterized in that: The electron density and satellite zenith distance are used as input parameters to input into the new altitude angle deviation correction method to obtain the angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle, including: Obtain the electron density value at the ionospheric puncture point; Calculate the satellite zenith distance from the observation data of the GNSS receiver; The electron density and the satellite zenith distance are passed as input parameters to the altitude angle deviation correction model, and the deviation correction model is executed to obtain the altitude angle deviation caused by the influence of the ionosphere; The original elevation angle of the satellite signal is obtained from the observation data of the GNSS receiver, and the calculated angle error is subtracted from the original elevation angle to obtain the corrected elevation angle; The corrected altitude angle is passed to the sea surface height calculation model, the sea surface height calculation model is executed, and the estimated value of the sea surface height is obtained by combining the receiver position, satellite position and signal propagation time.

7. A new GNSS-IR altitude angle deviation correction system, characterized in that: include: Establish a module for establishing a new altitude angle deviation correction method based on electron density through refraction angle relationship; The generation module is used to generate SNR files. The SNR files contain pseudo-random noise codes, azimuth, altitude, and S1C observation data for about 15,000 epochs per day. A calculation module is used to obtain the satellite zenith distance and position of the ionospheric puncture point using the Krobucher model, and input the Nequick-G model to calculate the electron density; The correction module is used to input electron density and satellite zenith distance as input parameters into a new altitude angle deviation correction method to obtain angle error, correct the altitude angle, and calculate the sea surface height with the corrected altitude angle.

8. A new GNSS-IR altitude angle deviation correction device, characterized in that: include: one or more processors; A storage system for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program, which, when executed by a processor, implements the method according to any one of claims 1 to 6.

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