Multi-path effect correction method and system based on regular hexagon grid, electronic equipment and storage medium

Abstract

The embodiment of the invention provides a multi-path effect correction method and system based on a regular hexagon grid, electronic equipment and a storage medium, and belongs to the technical field of satellite navigation and positioning. According to the scheme, data calculation is carried out on an observation value file and a broadcast ephemeris file to obtain a satellite residual error sequence and a corresponding elevation angle and an azimuth angle; dividing and coding the hemisphere grid based on the regular hexagon units to obtain a regular hexagon grid; mapping the satellite residual error sequence into a regular hexagon grid according to the elevation angle and the azimuth angle corresponding to the satellite residual error sequence to obtain a unit residual error sequence of each regular hexagon unit; performing statistical analysis on the residual sequence of each unit to obtain a multi-path correction value corresponding to the regular hexagonal unit; and performing error correction on the current observation value according to the multi-path correction value. According to the method, the data precision of space field modeling can be improved, accurate correction of a multi-path effect is realized, and thus the precision and reliability of satellite positioning in a shielding environment are improved.

Description

Technical Field

[0001] The present application relates to the technical field of satellite navigation and positioning, and particularly relates to a multipath effect correction method, system, electronic device and storage medium based on a regular hexagon grid. Background Art

[0002] High-precision positioning of Beidou / Global Navigation Satellite System (GNSS) is an important technical means in application fields such as geodetic surveying and navigation, civil engineering safety monitoring, and geological disaster monitoring. However, in practical applications, GNSS receiving devices are usually placed in occluded environments such as trees, buildings, and slopes, resulting in poor quality of GNSS observation data and large multipath effect errors, thereby reducing the accuracy and reliability of positioning.

[0003] When the relative position relationship between the occluder and the GNSS antenna is relatively fixed, domestic and foreign scholars have proposed methods such as sidereal day filtering and half-sky model to achieve multipath effect correction. However, the sidereal day filtering method requires calculating the precise satellite orbit repetition time of each satellite and storing a large amount of correction data; while the half-sky model stores correction numbers by dividing the observation environment into grids with altitude angle and azimuth angle as longitude and latitude lines, without calculating the satellite orbit time, so it has been widely used.

[0004] However, the current half-sky model is usually divided into 1°×1° quadrilateral grids according to altitude angle and azimuth angle. Although the regular quadrilateral is suitable for computer processing, storage, and calculation through an array structure, the quadrilateral has two different neighborhood relationships, namely the edge neighborhood and the diagonal neighborhood, making it have differences in model expression in two directions as a grid unit. At the same time, when dividing the half-sky grid with altitude angle and azimuth angle as longitude and latitude lines, the grid sizes of different longitudes are different, which is not conducive to the statistics and analysis of sampling points. Summary of the Invention

[0005] The main purpose of the embodiments of the present application is to propose a multipath effect correction method, system, electronic device and storage medium based on a regular hexagon grid, aiming to make the grid have consistent adjacency, improve the data accuracy of spatial field modeling, achieve precise correction of the multipath effect, and thus improve the accuracy and reliability of satellite positioning in occluded environments.

[0006] To achieve the above object, on the one hand, the embodiments of the present application propose a multipath effect correction method based on a regular hexagon grid, and the method includes:

[0007] Perform data calculation on the observation value file and the broadcast ephemeris file to obtain a satellite residual sequence and the corresponding altitude angle and azimuth angle;

[0008] Divide and code the hemispherical grid based on regular hexagonal cells to obtain a regular hexagonal grid;

[0009] According to the altitude angle and the azimuth angle corresponding to the satellite residual sequence, map the satellite residual sequence into the regular hexagonal grid to obtain the unit residual sequence of each regular hexagonal cell;

[0010] Perform statistical analysis on each unit residual sequence to obtain the multipath correction value corresponding to the regular hexagonal cell;

[0011] Perform error correction on the current observation value according to the multipath correction value.

[0012] In some embodiments, the dividing and coding the hemispherical grid based on regular hexagonal cells to obtain a regular hexagonal grid includes the following steps:

[0013] Divide the hemispherical grid into a plurality of regular hexagonal cells;

[0014] Taking the regular hexagonal cell at the center as a base point, perform multi-level coding on each regular hexagonal cell in a layer, vertex, and edge manner to obtain a grid code;

[0015] According to all the regular hexagonal cells and the corresponding grid codes, obtain a regular hexagonal grid.

[0016] In some embodiments, the taking the regular hexagonal cell at the center as a base point, performing multi-level coding on each regular hexagonal cell in a layer, vertex, and edge manner to obtain a grid code includes the following steps:

[0017] Taking the regular hexagonal cell at the center as a base point, perform layer coding on each regular hexagonal cell to obtain a layer code;

[0018] Taking the regular hexagonal cell at the center as a base point, perform vertex coding on each regular hexagonal cell to obtain a vertex code;

[0019] Taking the regular hexagonal cell at the center as a base point, perform edge coding on each regular hexagonal cell to obtain an edge code;

[0020] Perform coding conversion according to the layer code, the vertex code, and the edge code to obtain a grid code.

[0021] In some embodiments, the according to the altitude angle and the azimuth angle corresponding to the satellite residual sequence, mapping the satellite residual sequence into the regular hexagonal grid to obtain the unit residual sequence of each regular hexagonal cell includes the following steps:

[0022] Perform coordinate transformation based on the elevation angle and the azimuth angle corresponding to the satellite residual sequence to obtain the rectangular coordinates of each residual point;

[0023] Perform vector operation processing based on the rectangular coordinates and the regular hexagon grid to determine the regular hexagon unit where the residual point is located;

[0024] Based on all the residual points within each regular hexagon unit, obtain the corresponding unit residual sequence.

[0025] In some embodiments, the performing vector operation processing based on the rectangular coordinates and the regular hexagon grid to determine the regular hexagon unit where the residual point is located includes the following steps:

[0026] Obtain a point vector and a side vector based on the rectangular coordinates and the vertex coordinates of each regular hexagon unit, where the point vector represents the vector from the residual point to the vertex, and the side vector represents the vector from the vertex to the adjacent vertex;

[0027] Perform a vector product operation based on the point vector and the side vector to obtain a calculation result;

[0028] Determine the regular hexagon unit where the residual point is located based on the calculation result.

[0029] In some embodiments, the performing statistical analysis on each unit residual sequence to obtain the multipath correction value corresponding to the regular hexagon unit includes the following steps:

[0030] Perform a mean calculation process on the unit residual sequence to obtain a sequence mean;

[0031] Perform a standard deviation calculation process based on the sequence mean and the unit residual sequence to obtain a sequence standard deviation;

[0032] Perform an outlier rejection process on the unit residual sequence based on the sequence mean and the sequence standard deviation to obtain an error correction sequence;

[0033] Perform a mean calculation process on the error correction sequence to obtain an error correction mean;

[0034] Use the error correction mean as the multipath correction value corresponding to the regular hexagon unit.

[0035] In some embodiments, the performing an outlier rejection process on the unit residual sequence based on the sequence mean and the sequence standard deviation to obtain an error correction sequence includes the following steps:

[0036] Determine an outlier recognition threshold based on the sequence standard deviation;

[0037] Based on the abnormality identification threshold, judging whether the residual value is an abnormal value according to the absolute value of the difference between each residual value in the unit residual sequence and the sequence mean;

[0038] When the residual value is an outlier, a joint hypothesis test is performed on the outlier to obtain a test result, wherein the test result represents the degree of influence of the outlier on interval statistics;

[0039] The abnormal values in the unit residual sequence are eliminated according to the test results to obtain an error correction sequence.

[0040] To achieve the above object, another aspect of the embodiment of the present application provides a multipath correction system based on a regular hexagonal grid, the system comprising:

[0041] The first module is used to perform data analysis on the observation value file and the broadcast ephemeris file to obtain the satellite residual sequence and the corresponding altitude angle and azimuth angle;

[0042] The second module is used to divide and encode the semi-celestial grid based on regular hexagonal units to obtain a regular hexagonal grid;

[0043] A third module is used to map the satellite residual sequence to the regular hexagonal grid according to the altitude angle and the azimuth angle corresponding to the satellite residual sequence, so as to obtain a unit residual sequence of each regular hexagonal unit;

[0044] The fourth module is used to perform statistical analysis on each of the unit residual sequences to obtain a multipath correction value corresponding to the regular hexagonal unit;

[0045] The fifth module is used to perform error correction on the current observation value according to the multipath correction value.

[0046] To achieve the above objective, another aspect of an embodiment of the present application provides an electronic device, the electronic device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the above method when executing the computer program.

[0047] To achieve the above objective, another aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program implements the above method when executed by a processor.

[0048] The embodiments of the present application at least include the following beneficial effects: The present application provides a multipath effect correction method, system, electronic device and storage medium based on a regular hexagon grid. This solution performs data calculation on the observation value file and the broadcast ephemeris file to obtain the satellite residual sequence and the corresponding elevation angle and azimuth angle; divides and encodes the half-sky grid based on regular hexagon units to obtain a regular hexagon grid; maps the satellite residual sequence into the regular hexagon grid according to the elevation angle and azimuth angle corresponding to the satellite residual sequence to obtain the unit residual sequence of each regular hexagon unit; performs statistical analysis on each unit residual sequence to obtain the multipath correction value corresponding to the regular hexagon unit; corrects the error of the current observation value according to the multipath correction value. The present application can improve the data accuracy of spatial field modeling, achieve accurate correction of the multipath effect, and thus improve the accuracy and reliability of satellite positioning in an occluded environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a flowchart of the multipath effect correction method based on a regular hexagon grid provided by the embodiments of the present application;

[0050] Figure 2 is a half-sky grid diagram based on regular hexagon units provided by the embodiments of the present application;

[0051] Figure 3 is a coding schematic diagram of the regular hexagon grid provided by the embodiments of the present application;

[0052] Figure 4 is a schematic diagram of determining the relationship between the residual point and the grid position by the vector product method provided by the embodiments of the present application;

[0053] Figure 5 is a flowchart of the multipath effect correction method based on a regular hexagon grid provided by another embodiment of the present application;

[0054] Figure 6 is a schematic diagram of the multipath effect correction model of the half-sky grid based on regular hexagon units provided by the embodiments of the present application;

[0055] Figure 7 is a schematic diagram of the structure of the multipath effect correction system based on a regular hexagon grid provided by the embodiments of the present application;

[0056] Figure 8 is a schematic diagram of the hardware structure of the electronic device provided by the embodiments of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] In order to make the objectives, technical solutions, and advantages of this application clearer, the following further elaborates on this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. When the following description involves the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the embodiments of this application. They are merely examples of devices and methods that are consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0058] It can be understood that the terms "first", "second", etc. used in this application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, the first information may also be referred to as the second information. Similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" used herein may be interpreted as "when...", "while...", or "in response to determining".

[0059] The terms "at least one", "multiple", "each", "any one", etc. used in this application, at least one includes one, two, or more than two, multiple includes two or more than two, each refers to each of the corresponding multiple, and any one refers to any one of the multiple.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0061] Before specifically introducing the technical solutions of the embodiments of this application, first introduce the technical background or the context of the technical evolution based on which the embodiments of this application are developed.

[0062] In an occluded environment, GNSS signals will undergo effects such as reflection and diffraction, causing significant multipath effect errors, which reduce the accuracy and reliability of navigation and positioning. In the face of the characteristic that the positional relationship between the GNSS antenna and surrounding occluding objects is relatively fixed in application scenarios such as deformation monitoring, the embodiments of the present application provide a multipath effect correction method, system, electronic device, and storage medium based on a regular hexagonal grid. By performing data calculation on the observation value file and broadcast ephemeris file, a satellite residual sequence and corresponding elevation angle and azimuth angle are obtained; the half-sky grid is divided and encoded based on regular hexagonal cells to obtain a regular hexagonal grid; according to the elevation angle and azimuth angle corresponding to the satellite residual sequence, the satellite residual sequence is mapped into the regular hexagonal grid to obtain the cell residual sequence of each regular hexagonal cell; statistical analysis is performed on each cell residual sequence to obtain the multipath correction value corresponding to the regular hexagonal cell; the current observation value is corrected for error according to the multipath correction value, realizing precise correction of the multipath effect error and solving the problems of low GNSS positioning accuracy and insufficient reliability in an occluded environment.

[0063] The multipath effect correction method based on a regular hexagonal grid provided by the embodiments of the present application relates to the technical field of satellite navigation and positioning. The multipath effect correction method based on a regular hexagonal grid provided by the embodiments of the present application can be applied to a terminal, can also be applied to a server, or can be software running on a terminal or a server. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, a vehicle-mounted terminal, etc., but is not limited thereto; the server side can be configured as an independent physical server, can also be configured as a server cluster or distributed system composed of multiple physical servers, or can be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application that implements the multipath effect correction method based on a regular hexagonal grid, etc., but is not limited to the above forms.

[0064] This application can be used in numerous general or specific computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. This application can also be practiced in a distributed computing environment where tasks are executed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0065] Figure 1 is an optional flowchart of the multipath effect correction method based on a regular hexagonal grid provided by an embodiment of this application. Figure 1 The method in may include but is not limited to steps S101 to S105.

[0066] Step S101: Perform data solution on the observation value file and the broadcast ephemeris file to obtain the satellite residual sequence and the corresponding elevation angle and azimuth angle.

[0067] Step S102: Divide and encode the half-sky grid based on regular hexagonal cells to obtain a regular hexagonal grid.

[0068] Step S103: Map the satellite residual sequence into the regular hexagonal grid according to the elevation angle and azimuth angle corresponding to the satellite residual sequence to obtain the cell residual sequence of each regular hexagonal cell.

[0069] Step S104: Perform statistical analysis on each cell residual sequence to obtain the multipath correction value corresponding to the regular hexagonal cell.

[0070] Step S105: Correct the error of the current observation value according to the multipath correction value.

[0071] In this embodiment, for the observation data in an occluded environment, first, the satellite residual sequence and the corresponding elevation angle and azimuth angle are obtained through data solution.

[0072] Specifically, for the Beidou / GNSS of the reference station and the monitoring station in the actual positioning application scenario, select the observation value file and the broadcast ephemeris file for 10 consecutive days, and then use the post-processing double-difference relative positioning algorithm to solve the data and output the double-difference residual sequence, elevation angle, and azimuth angle of each satellite.

[0073] The post-hoc double-difference relative positioning algorithm is as follows: for the carrier phase and pseudo-range observation values of the reference station p and the monitoring station q, the double-difference observation equation is listed:

[0074]

[0075] in, is a double difference operator, the superscript i represents the satellite number, the subscript m represents the frequency number, P is the original pseudorange observation value, is the carrier phase observation value, in cycles; λ m is the wavelength of the carrier phase observation value of the mth frequency, ρ represents the geometric distance from the satellite to the receiver; N is the original carrier phase integer ambiguity parameter, in cycles; ε and ξ are the pseudorange and carrier phase observation value noise including multipath effect information, respectively.

[0076] The ambiguity of a continuous satellite arc is estimated as a parameter. Since the observation data is affected by noise and interference in the system, the estimation process of the system state can be regarded as a filtering process. Therefore, the Kalman filtering method can be used for parameter estimation. After parameter estimation, the floating point ambiguity solution of each ambiguity parameter is obtained. and its standard deviation σ N .

[0077] For example, formula (1) is written in matrix form for ease of calculation:

[0078] L k =A k X k +V k (2);

[0079] Where k is the current epoch, L k is the observation vector, namely the pseudorange and carrier phase observations, A k is the design matrix, X k is the state vector, including position parameters and ambiguity parameters, V k is the residual vector.

[0080] Furthermore, by combining equation (2) with the state transfer equation, we get the standard Kalman filter equation. The state transfer equation is expressed as:

[0081] X k+1 =Φ k+1,k X k +W k (3);

[0082] Among them, Φ k+1,k Represents the coefficient matrix of the state transfer equation, W k is zero-mean and its covariance matrix is Q Kof white Gaussian noise.

[0083] According to the obtained floating-point ambiguity solution and its standard deviation σ N calculate the success rate of ambiguity fixing, then sort them from largest to smallest success rate, and successively substitute the integer criteria for ambiguity fixing. If the criterion is satisfied, the ambiguity is fixed. Among them, the calculation formula for the success rate of ambiguity fixing is:

[0084]

[0085] The expression of the ambiguity fixing criterion is:

[0086]

[0087] Among them, n is the integer closest to the floating-point ambiguity solution α represents an empirical value, generally set to 0.1, that is, when the criterion exceeds 99.9%, it is considered that the ambiguity is reliably fixed. After the ambiguity is fixed, the fixed ambiguity will be substituted back into the Kalman filter equation for updated calculation to obtain the monitoring station position parameters (X, Y, Z) after ambiguity fixing and output the double-difference residual sequence, signal-to-noise ratio sequence, satellite elevation angle and azimuth angle sequence for each satellite and each epoch.

[0088]

[0089] Then divide the half-sky grid into grids with regular hexagons as units, and start from the regular hexagon unit at the center of the circle. Code each layer of regular hexagons in the order of layer, vertex, and edge. After coding, save the center point coordinates, vertex coordinates, etc. of each regular hexagon unit to obtain the regular hexagon grid. By adopting the regular hexagon grid division form, the grid has more consistent adjacency, and the hexagon is more isotropic, with higher data accuracy in spatial field modeling.

[0090] Map the satellite residual sequence obtained from data solution to the corresponding regular hexagon grid according to its elevation angle and azimuth angle to obtain the unit residual sequence of each regular hexagon unit, and then perform statistical calculations on the unit residual sequences within each regular hexagon unit to obtain the multipath correction value.

[0091] Exemplarily, for GPS, take the residual sequence for 1 consecutive day and its elevation angle and azimuth angle, for BDS, take the residual sequence for 7 consecutive days and its elevation angle and azimuth angle, and for Galileo, take the residual sequence for 10 consecutive days and its elevation angle and azimuth angle.

[0092] ​The coordinates of the residual points in the regular hexagon grid are solved using the altitude and azimuth angles of the residuals. All the residuals in the sequence are projected into the regular hexagon unit grids in the regular hexagon grid. According to all the residuals in the same regular hexagon unit grid, a unit residual sequence is formed. This sequence is a set of residuals in the same spatial direction and reflects the multipath error characteristics in the same spatial direction.

[0093] For each regular hexagon unit, statistical calculations are performed based on its corresponding unit residual sequence. The mean value of the sequence is calculated as the multipath correction value for this regular hexagon unit. By calculating the standard deviation of the sequence, the stability of the error is evaluated to assist in quality control.

[0094] A correction model is established based on the codes of all regular hexagon units and the multipath correction values corresponding to each regular hexagon unit for subsequent multipath effect correction of real-time observation values.

[0095] Specifically, during actual positioning, when the satellite moves into the occlusion area during its movement, based on the altitude and azimuth angles of the current observation values, the regular hexagon unit where the residual is located is determined, the code of this regular hexagon unit is obtained, and the code is input into the pre-stored correction model to query the multipath correction value of this regular hexagon unit to correct the current observation value, and positioning calculation is performed based on the corrected observation value.

[0096] In some embodiments, step S102 may include but is not limited to steps S201 to S203.

[0097] Step S201: Divide the hemisphere grid into several regular hexagon units.

[0098] Step S202: Taking the regular hexagon unit at the center as the base point, perform multi-level coding processing on each regular hexagon unit in the ways of layer, vertex, and edge respectively to obtain the grid code.

[0099] Step S203: Based on all regular hexagon units and their corresponding grid codes, obtain the regular hexagon grid.

[0100] In this embodiment, referring to Figure 2 , the hemisphere grid is divided into several regular hexagon units. Taking the regular hexagon unit at the center as the base point, six regular hexagon units surround the base point regular hexagon unit to form the second layer. After that, for each layer outwards, the number of hexagon units increases by six to form the next layer, and so on, spreading outwards layer by layer until the outermost regular hexagon units are exactly completely within the hemisphere grid. It should be noted that all regular hexagon units are of the same size.

[0101] The layer encoding is used to distinguish regular hexagonal units at different distances from the center of the circle. As the regular hexagonal unit at the center of the circle expands outward by one hexagonal ring, all the regular hexagonal units on the ring are assigned an encoding corresponding to the layer number according to the expanded layer number.

[0102] The vertex encoding is used to distinguish regular hexagonal units with different vertex directions in the same layer. Taking the six regular hexagonal units surrounding the regular hexagonal unit at the center of the circle as vertices, and taking the regular hexagonal unit in the upper left corner of the regular hexagonal unit at the center of the circle as the starting point, the encoding is 1, and the regular hexagonal units in the upper right corner, right side, lower right corner, lower left corner, and left side are encoded 2, 3, 4, 5, and 6 in clockwise order.

[0103] It can be understood that taking the regular hexagonal unit in the upper left corner as the starting point of the vertex encoding and encoding in clockwise direction is only exemplary. In actual applications, the encoding direction and starting vertex of the vertex encoding can be defined according to requirements, as long as the consistency of the vertex encoding requirements of all regular hexagonal units within the same hemisphere grid is ensured.

[0104] The edge encoding is used to further distinguish regular hexagonal units with the same layer and the same vertex direction, ensuring that each unit has a unique identifier. Taking the regular hexagonal units at the vertices of each layer as the starting points of the edge encoding, that is, the encodings of all regular hexagonal units at the vertices are 1. In the transition area between two adjacent vertices in the same layer, the space is further subdivided through the edge encoding. For example, in clockwise direction, the encoding value of the regular hexagonal unit is incremented one by one.

[0105] After the regular hexagonal units are respectively processed through the above three levels, a coding set including layer encoding, vertex encoding, and edge encoding will be obtained, as shown in (d) of Figure 3 According to the coding set after the three-level encoding, a unique grid encoding is determined for each regular hexagonal unit, and finally a regular hexagonal grid is formed, as shown in (e) of Figure 3

[0106] In some embodiments, step S202 may include but is not limited to steps S301 to S304.

[0107] Step S301: Taking the regular hexagonal unit at the center of the circle as the base point, perform layer encoding processing on each regular hexagonal unit to obtain the layer encoding.

[0108] Step S302: Taking the regular hexagonal unit at the center of the circle as the base point, perform vertex encoding processing on each regular hexagonal unit to obtain the vertex encoding.

[0109] Step S303: Taking the regular hexagonal unit at the center of the circle as the base point, perform edge encoding processing on each regular hexagonal unit to obtain the edge encoding. ​

[0110] Step S304: Perform encoding conversion based on the layer encoding, vertex encoding, and edge encoding to obtain the grid encoding.

[0111] In this embodiment, referring to Figure 3 (a) therein, the layer encoding process takes the regular hexagonal unit at the center of the circle as the first layer, with the layer encoding being 1. After each additional layer, the layer encoding of all regular hexagonal units in that layer is incremented by 1.

[0112] Referring to Figure 3 (b) therein, in the vertex encoding process, the vertex encoding of the first layer is 1. After each additional layer, starting from the regular hexagon in the upper left corner of that layer (encoded as 1), the vertices of the quasi - hexagon are sequentially encoded in a clockwise direction. Starting from the third layer, non - vertex edges appear in the quasi - hexagon, and the vertex encoding of the hexagons on the edge is the same as the vertex encoding of the vertex closest to it in the counter - clockwise direction.

[0113] Referring to Figure 3 (c) therein, the edge encoding at each vertex of each layer is 1. Starting from the third layer, non - vertex edges appear. The edges and all the hexagons with the same vertex encoding as them are grouped together, and the layer encoding is performed clockwise starting from the vertex.

[0114] In some embodiments, step S103 may include but is not limited to steps S401 to S403.

[0115] Step S401: Perform coordinate conversion based on the elevation angle and azimuth angle corresponding to the satellite residual sequence to obtain the rectangular coordinates of each residual point.

[0116] Step S402: Perform vector operation processing based on the rectangular coordinates and the regular hexagonal grid to determine the regular hexagonal unit where the residual point is located.

[0117] Step S403: Based on all the residual points within each regular hexagonal unit, obtain the corresponding unit residual sequence.

[0118] In this embodiment, first, the coordinates (elevation angle and azimuth angle) of the residuals are converted to a rectangular coordinate system, and the conversion formula is as follows:

[0119]

[0120] where Az is the azimuth angle, EL is the elevation angle, x Res is the abscissa, and y Res is the ordinate.

[0121] Next, the vector product is calculated using the rectangular coordinates of the residual points and the vertex coordinates of each regular hexagon unit in the regular hexagon grid to determine whether the residual points are within the regular hexagon unit grid. If the result of the vector product of the residual points and the vertices of a regular hexagon unit is positive, it is determined that the residual points are within the regular hexagon unit grid.

[0122] According to the observations corresponding to all the residual points in each regular hexagon unit, arrange them in chronological order or by satellite number to form a unit residual sequence.

[0123] In some embodiments, step S402 may include but is not limited to steps S501 to S503.

[0124] Step S501: Obtain the point vector and the edge vector according to the rectangular coordinates and the vertex coordinates of each regular hexagon unit, where the point vector represents the vector pointing from the residual point to the vertex, and the edge vector represents the vector pointing from the vertex to the adjacent vertex.

[0125] Step S502: Perform vector product operations according to the point vector and the edge vector to obtain the calculation result.

[0126] Step S503: Determine the regular hexagon unit where the residual point is located according to the calculation result.

[0127] In this embodiment, 12 vectors are connected between the residual point and the vertices of the regular hexagon unit grid, including 6 point vectors and 6 edge vectors respectively. The point vector represents the vector pointing from the residual point to the vertex, and the edge vector represents the vector pointing from the vertex to the adjacent vertex in the clockwise direction, as Figure 4 shown.

[0128] After obtaining the point vector and the edge vector according to the rectangular coordinates and the vertex coordinates of the regular hexagon unit, the vector product operations can be performed in sequence:

[0129]

[0130] Among them, is the point vector, representing respectively and is the edge vector, representing respectively and det is the determinant symbol, j i is the result of the i-th calculation.

[0131] Judge according to the calculation result j i If all the calculation results j i are positive, the residual point is within the regular hexagon unit to which the vertex belongs.

[0132] In some embodiments, step S104 may include, but is not limited to, steps S601 to S605.

[0133] Step S601, perform a mean calculation process on the unit residual sequence to obtain a sequence mean.

[0134] Step S602, perform a standard deviation calculation process based on the sequence mean and the unit residual sequence to obtain a sequence standard deviation.

[0135] Step S603, perform an outlier rejection process on the unit residual sequence based on the sequence mean and the sequence standard deviation to obtain an error correction sequence.

[0136] Step S604, perform a mean calculation process on the error correction sequence to obtain an error correction mean.

[0137] Step S605, use the error correction mean as the multipath correction value corresponding to the regular hexagon unit.

[0138] In this embodiment, the unit residual sequences of each regular hexagon unit are respectively statistically analyzed to obtain the corresponding sequence mean and the sequence standard deviation s:

[0139]

[0140] Based on the sequence mean and the sequence standard deviation s, outliers in the unit residual sequence are rejected. After removing all outliers that have a greater impact on the interval statistics, an error correction sequence is obtained.

[0141] When the outlier rejection process ends, the error correction sequence is averaged again, and the obtained error correction mean can be used as the multipath correction value of the regular hexagon unit.

[0142] In some embodiments, step S603 may include, but is not limited to, steps S701 to S704.

[0143] Step S701, determine an outlier recognition threshold based on the sequence standard deviation.

[0144] Step S702, based on the outlier recognition threshold, determine whether a residual value is an outlier according to the absolute value of the difference between each residual value in the unit residual sequence and the sequence mean.

[0145] Step S703, when the residual value is an outlier, perform a joint hypothesis test process on the outlier to obtain a test result, where the test result characterizes the impact degree of the outlier on the interval statistics.

[0146] Step S704, remove the outliers in the unit residual sequence according to the test result to obtain an error correction sequence.

[0147] In this embodiment, the 3σ criterion is adopted to determine the anomaly recognition threshold according to the sequence standard deviation. Assume that the unit residual sequence in the I-th regular hexagon unit is whose sequence mean and standard deviation are respectively and s I . If then it is considered that is an outlier.

[0148] Use the joint hypothesis test (also known as the F-test) to detect the influence of this outlier on the entire interval, that is:

[0149]

[0150] where f I,1 = n I,1 -1 and f I,2 = n I,2 -1 are the degrees of freedom, n I,1 and n I,2 are the numbers of residual points in the set with and without this outlier. If is significantly greater than then it means that this outlier has a greater influence on the interval statistics and should be removed.

[0151] By iterating the above process until all outliers are removed, when the above test process ends, an error correction sequence is obtained according to the remaining residual values.

[0152] Next, in combination with specific application examples, the solution of the embodiment of the present invention will be introduced and described in detail.

[0153] This application belongs to the field of satellite navigation and positioning, and specifically relates to the high-precision navigation and positioning and deformation monitoring applications of GNSS. Refer to Figure 5 . Figure 5 For the multipath effect correction method based on a regular hexagon grid provided in another embodiment of this application, the method may include but is not limited to steps S801 to S805.

[0154] Step S801: Read the observation files and ephemeris files of the reference station and the monitoring station for 10 consecutive days, use the post-double-difference relative positioning algorithm to solve the data, and output the double-difference residual sequences, elevation angles, and azimuth angles of each satellite.

[0155] Step S802: Divide the half-sky grid based on the regular hexagon unit.

[0156] Step S803: Map the residuals and their elevation angles and azimuth angles to the corresponding regular hexagon grid.

[0157] Step S804: Conduct statistical analysis on the residual sequences within each grid and calculate the multipath correction value.

[0158] Step S805: Determine the correction number within the corresponding grid according to the elevation angle and azimuth angle of the current observation value, and perform error correction.

[0159] Specifically, a data acquisition platform is built on the roof. Among them, the reference station (BASE) is built on the first roof, and the monitoring station is located on the second roof. The monitoring station is severely blocked by surrounding buildings and trees, and the baseline length is 103 meters. Both stations are equipped with multi-frequency and multi-mode GNSS receivers and supporting antennas. The receiver is set to receive observation data of the GPS / BDS-2 / BDS-3 / GALILEO satellite systems, the sampling frequency is set to 5s, and each 4 hours is a time period for storage and calculation. In the project, data transmission uses LoRa wireless network transmission, and the GNSS data management software is responsible for receiving and storing.

[0160] The test data adopted in this embodiment are Beidou-2 / Beidou-3 / GPS / Galileo observation data for 10 consecutive days, and the sampling frequency is 5s. First, the residual sequence and the corresponding elevation angle and azimuth angle sequences are obtained through data processing. Then, the hemisphere is divided into grids with regular hexagons as units, and the residual information is statistically calculated according to the grids to construct a multi-path effect correction model for the hemisphere grid based on regular hexagon units, as Figure 6 shown, which can realize multi-path effect error correction and solve the problems of low GNSS positioning accuracy and insufficient reliability in an occluded environment.

[0161] From Figure 6 it can be seen that the model can effectively express the error distribution in the observation environment, estimate the carrier phase residuals, calculate the correction value through data quality control of the residuals within each grid, and different colors represent multi-path correction values in different numerical ranges.

[0162] Finally, use the product of the residual coordinates (elevation angle and azimuth angle) of the current observation value and the grid coordinate vector (Formula 7) to determine the grid I where the residual point is located, and take the model correction number of this grid.

[0163] C(az,el)=grid I (x)(11);

[0164] where az and el respectively represent the azimuth angle and elevation angle of the current observation value.

[0165] It should be noted that the regular hexagon grid provided in the embodiments of the present application can also be applied to diffraction error correction. Although the diffraction error has a different generation mechanism from the multipath effect, its spatio-temporal distribution characteristics are similar to those of the multipath effect, and both can be eliminated by the grid method. Therefore, the diffraction error can be regarded as a kind of multipath effect error, and the diffraction error correction can be carried out by the multipath effect correction method based on the regular hexagon grid provided in the present application.

[0166] In summary, the multipath effect correction method based on the regular hexagon grid provided in the present application uses the GNSS post-double-difference relative positioning algorithm for positioning and calculation. The observations of the entire ambiguity arc segment can be used to fix the ambiguity, which is beneficial to retaining the observation residuals affected by occlusion, and outputting the double-difference residual sequence and the elevation angle and azimuth angle sequence.

[0167] The regular hexagon cell grid has more consistent adjacency, that is, 6 neighboring cells are all adjacent to the central grid by edges and have the same distance from the central grid. This characteristic gives the hexagon certain advantages in dealing with neighborhood processing problems such as the nearest neighbor and moving paths.

[0168] In the case of the same area, the hexagon is closer to a circle, and its grid structure is more compact. Compared with the quadrilateral structure, it has higher data accuracy with the same amount of data. In addition, the hexagon is more isotropic and has more advantages in spatial field modeling.

[0169] Refer to Figure 7 , the embodiments of the present application also provide a multipath effect correction system based on the regular hexagon grid, which can implement the multipath effect correction method based on the regular hexagon grid. The system includes:

[0170] The first module is used to perform data calculation on the observation value file and the broadcast ephemeris file to obtain the satellite residual sequence and the corresponding elevation angle and azimuth angle.

[0171] The second module is used to divide and encode the hemispherical grid based on the regular hexagon cells to obtain the regular hexagon grid.

[0172] The third module is used to map the satellite residual sequence into the regular hexagon grid according to the elevation angle and azimuth angle corresponding to the satellite residual sequence to obtain the unit residual sequence of each regular hexagon cell.

[0173] The fourth module is used to perform statistical analysis on each unit residual sequence to obtain the multipath correction value corresponding to the regular hexagon cell.

[0174] The fifth module is used to correct the current observation value according to the multipath correction value.

[0175] It can be understood that the content in the above method embodiments is applicable to the system embodiments of the present invention. The functions specifically implemented in the system embodiments of the present invention are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those in the above method embodiments.

[0176] An embodiment of the present application further provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the above multi-path effect correction method based on a regular hexagonal grid. The electronic device can be any intelligent terminal including a tablet computer, an in-vehicle computer, etc.

[0177] It can be understood that the content in the above method embodiments is applicable to the device embodiments of the present invention. The functions specifically implemented in the device embodiments of the present invention are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those in the above method embodiments.

[0178] Refer to Figure 8 , Figure 8 FIG. schematically shows the hardware structure of an electronic device according to another embodiment. The electronic device includes:

[0179] A processor 901, which can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided by the embodiments of the present application.

[0180] A memory 902, which can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM), etc. The memory 902 can store an operating system and other application programs. When implementing the technical solutions provided by the embodiments of the present specification through software or firmware, the relevant program codes are stored in the memory 902 and are called by the processor 901 to execute the multi-path effect correction method based on a regular hexagonal grid in the embodiments of the present application.

[0181] An input / output interface 903, which is used to implement information input and output.

[0182] A communication interface 904, which is used to implement communication interaction between the device and other devices, and can implement communication through a wired method (such as USB, network cable, etc.) or through a wireless method (such as a mobile network, WIFI, Bluetooth, etc.).

[0183] The bus 905 transmits information among various components of the device (such as the processor 901, the memory 902, the input / output interface 903, and the communication interface 904).

[0184] Among them, the processor 901, the memory 902, the input / output interface 903, and the communication interface 904 achieve communication connections with each other inside the device through the bus 905.

[0185] The embodiment of the present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the above-mentioned multi-path effect correction method based on a regular hexagonal grid.

[0186] It can be understood that the content in the above method embodiments is applicable to the present storage medium embodiment. The functions specifically implemented by the present storage medium embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0187] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs and non-transitory computer-executable programs. In addition, the memory can include high-speed random access memory, and can also include non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely set relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0188] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0189] Those skilled in the art can understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or combine certain steps, or different steps.

[0190] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0191] Those of ordinary skill in the art will understand that all or some of the steps in the methods disclosed above, and the functional modules / units in systems and devices, can be implemented as software, firmware, hardware, or a suitable combination thereof.

[0192] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of this application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of this application described here can be implemented in an order different from those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0193] The preferred embodiments of the embodiments of this application have been described above with reference to the drawings, and thus do not limit the scope of the rights of the embodiments of this application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of this application shall be within the scope of the rights of the embodiments of this application.

Claims

1. A multi-path effect correction method based on a regular hexagonal grid, characterized in that, The method includes the following steps: Perform data calculation on the observation value file and the broadcast ephemeris file to obtain a satellite residual sequence and the corresponding altitude angle and azimuth angle; Divide and encode the hemispherical grid based on regular hexagonal cells to obtain a regular hexagonal grid; According to the altitude angle and the azimuth angle corresponding to the satellite residual sequence, map the satellite residual sequence into the regular hexagonal grid to obtain a cell residual sequence for each regular hexagonal cell; Perform statistical analysis on each cell residual sequence to obtain the multipath correction value corresponding to the regular hexagonal cell; Perform error correction on the current observation value according to the multipath correction value.

2. The method according to claim 1, wherein The step of dividing and encoding the hemispherical grid based on regular hexagonal cells to obtain a regular hexagonal grid includes the following steps: Divide the hemispherical grid into several regular hexagonal cells; Taking the regular hexagonal cell at the center of the circle as the base point, perform multi-level encoding processing on each regular hexagonal cell in the ways of layer, vertex, and edge respectively to obtain a grid encoding; According to all the regular hexagonal cells and the corresponding grid encodings, obtain a regular hexagonal grid.

3. The method according to claim 2, characterized in that, The step of taking the regular hexagonal cell at the center of the circle as the base point and performing multi-level encoding processing on each regular hexagonal cell in the ways of layer, vertex, and edge respectively to obtain a grid encoding includes the following steps: Taking the regular hexagonal cell at the center of the circle as the base point, perform layer encoding processing on each regular hexagonal cell to obtain a layer encoding; Taking the regular hexagonal cell at the center of the circle as the base point, perform vertex encoding processing on each regular hexagonal cell to obtain a vertex encoding; Taking the regular hexagonal cell at the center of the circle as the base point, perform edge encoding processing on each regular hexagonal cell to obtain an edge encoding; Perform encoding conversion according to the layer encoding, the vertex encoding, and the edge encoding to obtain a grid encoding.

4. The method according to claim 1, characterized in that The step of mapping the satellite residual sequence into the regular hexagonal grid according to the altitude angle and the azimuth angle corresponding to the satellite residual sequence to obtain a cell residual sequence for each regular hexagonal cell includes the following steps: Perform coordinate conversion according to the altitude angle and the azimuth angle corresponding to the satellite residual sequence to obtain the rectangular coordinates of each residual point; Perform vector operation processing according to the rectangular coordinates and the regular hexagonal grid to determine the regular hexagonal cell where the residual point is located; Based on all the residual points in each regular hexagonal cell, obtain the corresponding cell residual sequence.

5. The method according to claim 4, wherein The step of performing vector operation processing according to the rectangular coordinates and the regular hexagonal grid to determine the regular hexagonal cell where the residual point is located includes the following steps: Obtain a point vector and an edge vector according to the rectangular coordinates and the vertex coordinates of each regular hexagonal cell, where the point vector represents the vector from the residual point to the vertex, and the edge vector represents the vector from the vertex to the adjacent vertex; Perform vector product operation according to the point vector and the edge vector to obtain a calculation result; Determine the regular hexagonal cell where the residual point is located according to the calculation result.

6. The method according to claim 1, wherein The step of performing statistical analysis on each cell residual sequence to obtain the multipath correction value corresponding to the regular hexagonal cell includes the following steps: Perform mean calculation processing on the unit residual sequence to obtain the sequence mean; Perform standard deviation calculation processing based on the sequence mean and the unit residual sequence to obtain the sequence standard deviation; Perform outlier rejection processing on the unit residual sequence according to the sequence mean and the sequence standard deviation to obtain the error correction sequence; Perform mean calculation processing on the error correction sequence to obtain the error correction mean; Use the error correction mean as the multipath correction value corresponding to the regular hexagon unit.

7. The method according to claim 6, wherein The performing outlier rejection processing on the unit residual sequence according to the sequence mean and the sequence standard deviation to obtain the error correction sequence includes the following steps: Determine the outlier recognition threshold according to the sequence standard deviation; Based on the outlier recognition threshold, determine whether the residual value is an outlier according to the absolute value of the difference between each residual value in the unit residual sequence and the sequence mean; When the residual value is an outlier, perform joint hypothesis testing processing on the outlier to obtain a test result, where the test result characterizes the influence degree of the outlier on interval statistics; Perform outlier rejection processing on the outlier in the unit residual sequence according to the test result to obtain the error correction sequence.

8. A multipath effect correction system based on a regular hexagon grid, characterized in that The system includes: A first module for performing data solution on the observation value file and the broadcast ephemeris file to obtain the satellite residual sequence and the corresponding elevation angle and azimuth angle; A second module for dividing and coding the hemisphere grid based on the regular hexagon unit to obtain the regular hexagon grid; A third module for mapping the satellite residual sequence into the regular hexagon grid according to the elevation angle and the azimuth angle corresponding to the satellite residual sequence to obtain the unit residual sequence of each regular hexagon unit; A fourth module for performing statistical analysis on each unit residual sequence to obtain the multipath correction value corresponding to the regular hexagon unit; A fifth module for performing error correction on the current observation value according to the multipath correction value.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that, The computer program implements the method according to any one of claims 1 to 7 when executed by the processor.

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