A method for inverse calculation, encryption and release of coordinate conversion parameters of a large-rotation-angle independent coordinate system

Abstract

The present application relates to the field of satellite positioning and navigation technology, in particular to a kind of big rotation angle independent coordinate system's coordinate conversion parameter counter calculation, encryption and release method, the present application is by combining plane four parameters and virtual seven parameters, break through the precision bottleneck of traditional model under high rotation angle, realized millimeter level coordinate conversion precision.Parameter encryption mechanism protects sensitive information in conversion, through user information generates matched virtual parameter to ensure data security.Combined with CORS service system, real-time parameter release is realized through RTCM protocol, and users can conveniently apply coordinates through GNSS equipment, meet the high-precision requirements of airport construction, aviation navigation and other fields, and improve the flexibility and applicability of coordinate conversion.

Description

Technical Field

[0001] This invention relates to the field of satellite positioning and navigation technology, specifically to a method for inverse calculation, encryption, and publication of coordinate transformation parameters in a large rotation angle independent coordinate system. Background Technology

[0002] With the increasing application of satellite positioning technology in airport construction and management, CORS systems have become a crucial support for high-precision positioning. However, core airport operational areas generally employ dedicated airport-independent coordinate systems, which are established based on the runway centerline using the "one point, one orientation" principle. This construction method results in a significant large rotation angle characteristic between CORS and geodetic coordinate systems (such as CGCS2000). Traditional CORS coordinate publishing technology relies on a seven-parameter transformation model, but this model cannot meet the transformation requirements of the RTCM32 protocol under large rotation angle scenarios, leading to a severe loss of transformation accuracy and making it difficult to support the millimeter-level accuracy requirements of airport construction and aircraft navigation.

[0003] Furthermore, the coordinate system transformation parameters themselves involve spatial information of the airport's core infrastructure, which constitutes sensitive and classified data. Current technology lacks a mechanism for protecting these transformation parameters; directly using or transmitting unencrypted parameters would pose significant security risks. Current geographic information data processing workflows lack both reliable transformation methods for large rotation angles and effective technical means to ensure parameter confidentiality.

[0004] Therefore, there is an urgent need for a solution that balances adaptability to large rotation angles and parameter confidentiality: on the one hand, it is necessary to break through the application limitations of the traditional seven-parameter model in large rotation angle scenarios and achieve high-precision coordinate transformation; on the other hand, it is necessary to encrypt the transformation parameters through technical means to ensure the security and controllability of confidential data throughout the entire process of release, transmission and application. Summary of the Invention

[0005] The purpose of this invention is to provide a method for inverse calculation, encryption, and publication of coordinate transformation parameters for a large rotation angle independent coordinate system, which solves the problems of low accuracy and poor confidentiality of existing CORS publication technology in large rotation angle scenarios. This invention provides a technical method for real-time and accurate publication of airport independent coordinate system CORS data to meet the high-precision measurement needs of airport construction, aircraft navigation, and other fields, as well as the problem of encrypting coordinate parameters during the coordinate transformation process of surveying and mapping geographic information data.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A method for inverse calculation, encryption, and publication of coordinate transformation parameters in a large rotation angle independent coordinate system includes the following steps: S1: Obtain the geographic coordinate system results, independent coordinate system results, and approximate projection parameters of the independent coordinate system for the control points with the same name. The approximate projection parameters include, but are not limited to, ellipsoid parameters, projection central meridian, and compensation surface elevation. S2: Based on the geographic coordinate system results and the independent coordinate system results, calculate the approximate four-parameter plane parameters for converting the geographic coordinate system to the independent coordinate system. The approximate four-parameter plane parameters include translation parameters. Rotation parameters and scale parameters ; S3: Approximate the four plane parameters to generate virtual four plane parameters, including: rounding the translation parameter to the kilometer level, rounding the rotation parameter to the minute level, and the scale parameter... Round to the nearest ppm or 1; S4: Using the four parameters of the virtual plane, the independent coordinate system results are inversely calculated into approximate Gaussian projection coordinates; S5: Perform Gaussian inverse calculation on the approximate Gaussian projection coordinates according to the approximate central meridian to obtain approximate geodetic coordinates; S6: Construct virtual seven parameters based on seven random parameters of user information, wherein the virtual seven parameters include spatial rectangular coordinate translation ( ), rotation angle ( and scale parameters , among which | |、| |、| | is a random number less than 300m, | |、| |、| | is a random number less than 3 seconds, and the scale parameter k satisfies: k = 1 + a, |a| < 10 × 10 -6 ; S7: Based on user information, generate and associate a set of paired virtual conversion parameters, which include the virtual plane four parameters generated in step S3 and the virtual seven parameters generated in step S4; the user information includes unit information, registration account, hardware code, software dongle or registration code; S8: Based on the CORS service system, the virtual seven parameters and ellipsoid parameters are broadcast to the user via the RTCM protocol, and the user is guided to enter the paired virtual plane four parameters in the GNSS RTK handheld device; S9: Based on the coordinate transformation system, the user-input coordinates are transformed using paired virtual plane four-parameters and virtual seven-parameters, and the results are output in an independent coordinate system.

[0007] Furthermore, the calculation of the four plane parameters in step S2 includes the following sub-steps: S2.1: Obtain the geodetic coordinates of the corresponding control points. and results of independent coordinate systems B is latitude, L is longitude, a is the north coordinate of the independent coordinate system, b is the east coordinate of the independent coordinate system, and i is the control point number (i=1, 2, 3, ..., n). S2.2: The central meridian of the independent coordinate system is approximated and then processed to obtain the approximate central meridian, which is retained to the minute. S2.3: Results using the geodetic coordinate system of control points According to the general outline and approximate unified central meridian of the independent coordinate system Perform a transposition projection to obtain its Gaussian projection coordinates after the transposition. ; S2.4: Using the Gaussian projection coordinates after the belt change and results of independent coordinate systems Calculate its four plane parameters according to the four-parameter plane model. ,in There are two translation parameters. For rotation parameters, This is the scale parameter.

[0008] Furthermore, the inverse calculation process in step S4 includes the following sub-steps: S4.1: Using the four parameters of a virtual plane Construct a four-parameter transformation model; S4.2: Obtain approximate Gaussian projection coordinates by back-calculating the results of the independent coordinate system using the model described above. .

[0009] Furthermore, the coordinate transformation system in step S9 includes the following sub-steps: S9.1: User input is geodetic coordinates P i (B, L), convert it to spatial rectangular coordinates (X, Y, Z); S9.2: Based on seven random parameters from user information, the spatial rectangular coordinates P i (X, Y, Z) transformed into P i (X1, Y1, Z1); S9.3: Using virtual seven parameters to P i (X1, Y1, Z1) converted to intermediate space rectangular coordinates P i (X2, Y2, Z2); S9.4: P i (X2, Y2, Z2) converted to approximate geodetic coordinates P i (B2, L2); S9.5: Based on the approximate central meridian P i (B2, L2) is projected as Gaussian projection coordinates Pi (x2, y2); S9.6: Using the four parameters of the virtual plane to P i The result of converting (x2, y2) to an independent coordinate system is P. i (a, b).

[0010] Furthermore, when the user inputs Gaussian plane coordinates, they need to be converted back to geodetic coordinates according to the approximate central meridian before executing sub-steps S9.1 to S9.6; wherein, the Gaussian plane coordinates are generated based on the approximate central meridian.

[0011] Furthermore, the CORS service system publishing process in step S8 specifically includes: S8.1 The virtual seven parameters and ellipsoid parameters are broadcast to the user's GNSS equipment in real time via the RTCM protocol message type (such as MSM7 or a custom message type); S8.2 Embed a user identity verification identifier in the broadcast data stream, which is associated with the user information in step S7; S8.3 The user's GNSS RTK handheld device automatically parses the virtual seven parameters in the RTCM data stream and triggers the virtual plane four-parameter input guide interface; S8.4 After the user enters the paired virtual plane four parameters according to the guidance, the handheld device integrates the virtual seven parameters broadcast by the RTCM with the locally entered virtual plane four parameters in real time to achieve real-time dynamic positioning in an independent coordinate system.

[0012] The beneficial effects of this invention are: This invention addresses the scenario of independent coordinate systems with large rotation angles. It generates paired virtual four-parameter parameters (including translation, rotation, and scale parameters) and virtual seven-parameter parameters (including translation and rotation parameters for spatial rectangular coordinates) based on user-related information. This effectively ensures the confidentiality of transformation parameters while significantly enhancing the accuracy of coordinate transformation, achieving a rigorous conversion from geodetic coordinates to an independent coordinate system. By approximating the transformation parameters in large units of measurement, the impact of large rotation angles on the accuracy of independent coordinate system transformations is fully compensated. This enables millimeter-level accuracy in high-precision independent coordinate system transformation and deployment scenarios, such as airport construction and air navigation systems. It overcomes the accuracy bottleneck of traditional seven-parameter models under large rotation angles.

[0013] To address the confidentiality requirements of coordinate transformation parameters as sensitive data, this invention provides an encrypted protection layer for the coordinate transformation process through the random generation and use of virtual parameters. Based on the user's registration information and hardware characteristics, the system generates a unique pair of virtual four-parameters and virtual seven-parameters. These parameters are decrypted and used only on the user's end, ensuring data security during transmission and storage. This effectively avoids the risk of leakage of sensitive coordinate data, especially in scenarios involving critical infrastructure such as airports, ensuring the security and confidentiality of geographic information.

[0014] This invention allows for the random generation of virtual conversion parameters based on specific user information. This gives the system high flexibility and adaptability, enabling adaptive configuration of conversion parameters according to user needs and usage environment. Different users can obtain virtual parameters bound to their information in different hardware environments, which not only improves system security but also increases user convenience and the system's applicability. This system can be quickly deployed and used in various application scenarios without complex reconfiguration.

[0015] This invention integrates with the CORS service system and broadcasts conversion parameters in real time via the RTCM protocol, enabling parameter application without the need for physical media transmission. This simplifies the user's workflow; users only need to input virtual four parameters through a GNSS RTK device to perform precise coordinate transformations. This makes the invention more efficient and convenient in practical use, adaptable to a wide range of high-precision positioning coordinate transformation and CORS-based independent coordinate system publishing needs, including but not limited to airport operation management, aircraft navigation, and other fields involving high-precision geographic information transformation.

[0016] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A map showing the distribution of control points in the CGCS2000 coordinate system; Figure 2 A map showing the distribution of control points in an independent coordinate system; Figure 3 This diagram illustrates the process of converting geodetic coordinate results into results for an independent coordinate system. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 The method for inverse calculation, encryption, and publication of coordinate transformation parameters in a large rotation angle independent coordinate system described in this embodiment includes the following steps: S1: Obtain the geographic coordinate system results, independent coordinate system results, and approximate projection parameters of the independent coordinate system for the control points with the same name. The approximate projection parameters include, but are not limited to, ellipsoid parameters, projection central meridian, and compensation surface elevation. S2: Based on the geographic coordinate system results and the independent coordinate system results, calculate the approximate four-parameter plane parameters for converting the geographic coordinate system to the independent coordinate system. The approximate four-parameter plane parameters include translation parameters. Rotation parameters and scale parameters ; S3: Approximate the four plane parameters to generate virtual four plane parameters, including: rounding the translation parameter to the kilometer level, rounding the rotation parameter to the minute level, and the scale parameter... Round to the nearest ppm or 1; S4: Using the four parameters of the virtual plane, the independent coordinate system results are inversely calculated into approximate Gaussian projection coordinates; S5: Perform Gaussian inverse calculation on the approximate Gaussian projection coordinates according to the approximate central meridian to obtain approximate geodetic coordinates; S6: Construct virtual seven parameters based on seven random parameters of user information, wherein the virtual seven parameters include spatial rectangular coordinate translation ( ), rotation angle ( and scale parameters , among which | |、| |、| |<300m, a random number,| |、| |、| |<3 seconds, scale parameter k=1; Among them | |、| |、| | is a random number less than 300; the scale parameter k satisfies: k = 1 + a, |a| < 10 × 10 -6 ; S7: Based on user information, generate and associate a set of paired virtual conversion parameters, which include the virtual plane four parameters generated in step S3 and the virtual seven parameters generated in step S4; the user information includes unit information, registration account, hardware code, software dongle or registration code; S8: Based on the CORS service system, the virtual seven parameters and ellipsoid parameters are broadcast to the user via the RTCM protocol, and the user is guided to enter the paired virtual plane four parameters in the GNSS RTK handheld device; S9: Based on the coordinate transformation system, the user-input coordinates are transformed using paired virtual plane four-parameters and virtual seven-parameters, and the results are output in an independent coordinate system.

[0021] Example 2 A method for inverse calculation, encryption, and publication of coordinate transformation parameters in a large rotation angle independent coordinate system, the method comprising: S1: Obtain the geographic coordinate system results and independent coordinate system results of the control points with the same name, as well as the approximate projection parameters of the independent coordinate system, such as approximate ellipsoid parameters, projection central meridian and compensation surface elevation, etc.

[0022] S2: Based on the above results, the geographic coordinate system results of the preliminary control points are converted into the four plane parameters of the independent coordinate system results.

[0023] S3: Using the estimated four-parameter plane parameters, construct virtual four-parameter and virtual seven-parameter plane parameters.

[0024] S4: By constructing virtual four-parameter and virtual seven-parameter parameters, geographic coordinate system results are converted into independent coordinate system results, ensuring the consistency of the conversion results.

[0025] S5: Based on the user information, randomly construct virtual four-parameter and virtual seven-parameter according to step 3) above to realize the construction of virtual parameters of the independent coordinate system of the user information.

[0026] S6: Based on the CORS service system, according to user information, using paired transformation parameters, and using RTCM to broadcast ellipsoidal parameters, virtual seven parameters and other information, the user terminal enters virtual four parameters, realizing the CORS large rotation angle independent coordinate system publishing service.

[0027] S7: Based on the coordinate transformation system, coordinate transformation is performed using paired transformation parameters according to user information to obtain the correct independent coordinate system results.

[0028] In this embodiment, the geographic coordinate system results of the preliminary control points are converted into plane four-parameter results in an independent coordinate system. The distribution of control points is as follows: Figure 1 As shown.

[0029] Preliminary calculation of four plane parameters Obtain geodetic coordinates of control points with the same name and results of independent coordinate systems B is latitude, L is longitude, a is the north coordinate of the independent coordinate system, b is the east coordinate of the independent coordinate system, and i is the control point number (i=1, 2, 3, ..., n). Table 1 Geographic coordinates of control points (degrees, minutes, seconds) Table 2 Results of the Independent Coordinate System for Control Points Central meridian of an independent coordinate system =102.5632532 (degrees, minutes, seconds), approximated to obtain the approximate central meridian. =102.56 (rounded to the nearest minute, i.e., 102°56′); Using the geodetic coordinate system results of control points According to the approximate central meridian of the independent coordinate system Perform a transposition projection to obtain its Gaussian projection coordinates after the transposition. ; Table 3 Approximate Projected Coordinates of Control Points Central Meridian Using Gaussian projection coordinates after tape change and results of independent coordinate systems Calculate its four plane parameters according to the four-parameter plane model. ,in There are two translation parameters. For rotation parameters, This is the scale parameter.

[0030] Four parameters for preliminary calculation: (-1327776.5695, -2483018.5077, 51.6036998825275, 1.00032678140634); In this embodiment, constructing the virtual four parameters and the virtual seven parameters includes: Constructing virtual four parameters For the four parameters of the plane Approximate operations can be performed (or constructed by adding random numbers based on user information), such as translation parameters. Round to the nearest kilometer, rotation parameters Take the score, scale parameter Taking values ​​up to ppm or 1, we obtain approximate planar four parameters. ; Approximate four parameters: (-1330000, -2480000, 51.6, 1); Calculate approximate geodetic coordinates The results of the independent coordinate system are used to apply virtual four-parameter plane parameters. And the four-parameter model, the approximate Gaussian projection coordinates corresponding to the results of the inverse calculation of the independent coordinate system. ; Table 4. Inverse calculation of plane coordinates from control point independent coordinate system results Gaussian projection coordinates calculated by inverse method According to the approximate central meridian =102.56, Gaussian inverse calculation to geodetic coordinates ; Table 5. Inverse Plane Coordinates of Control Points Inverse calculation of geodetic coordinates Constructing virtual seven parameters Geodetic coordinates of control points Convert to spatial rectangular coordinates Table 6 Geodetic coordinates of control points Convert to spatial rectangular coordinates geodetic coordinates Convert to spatial rectangular coordinates Table 7 Geodetic coordinates of control points Convert to spatial rectangular coordinates Table 8. Approximate Spatial Rectangular Coordinates of Control Points Using a seven-parameter model, calculate and The seven parameters between ; In this embodiment, a constructed virtual four-parameter parameter is used. and virtual seven parameters , To achieve coordinate transformation; such as Figure 3 As shown; Geodetic coordinate results Results of conversion to independent coordinate system The process is as follows: Convert to spatial rectangular coordinates ; Using seven parameters , converted ; Using seven parameters , converted ; Convert to geodetic coordinates ; According to the approximate central meridian Convert to Gaussian plane coordinates ; Using the four plane parameters Convert to airport ab coordinates. If Pi is in Gaussian projected coordinates, it needs to be converted to geodetic coordinates first.

[0031] In this embodiment, based on user information (including but not limited to unit information, registered account, hardware code, software dongle, registration code, etc.), matching virtual conversion parameters can be randomly generated according to step S3.

[0032] In this embodiment, based on the CORS service system and the aforementioned paired virtual transformation parameters, the coordinates of the independent coordinate system results are published, such as... Figure 3 As shown: Randomly generate paired virtual transformation parameters , and four parameters ; Using CORS RTCM to broadcast seven parameters ; Using a GNSS RTK handheld device, four parameters were entered; In this embodiment, coordinate transformation of independent coordinate system results is achieved based on the coordinate transformation system and the aforementioned paired virtual transformation parameters.

[0033] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for inverse calculation, encryption and release of coordinate conversion parameters of a large-rotation-angle independent coordinate system, characterized in that, Includes the following steps: S1: Obtain the geographic coordinate system results, independent coordinate system results, and approximate projection parameters of the independent coordinate system for the control points with the same name. The approximate projection parameters include, but are not limited to, ellipsoid parameters, projection central meridian, and compensation surface elevation. S2: Based on the geographic coordinate system results and the independent coordinate system results, calculate the approximate four-parameter plane parameters for converting the geographic coordinate system to the independent coordinate system. The approximate four-parameter plane parameters include translation parameters. Rotation parameters and scale parameters ; S3: Approximate the four plane parameters to generate virtual four plane parameters, including: rounding the translation parameter to the kilometer level, rounding the rotation parameter to the minute level, and the scale parameter... Round to the nearest ppm or 1; S4: Using the four parameters of the virtual plane, the independent coordinate system results are inversely calculated into approximate Gaussian projection coordinates; S5: Perform Gaussian inverse calculation on the approximate Gaussian projection coordinates according to the approximate central meridian to obtain approximate geodetic coordinates; S6: Construct virtual seven parameters based on seven random parameters of user information, wherein the virtual seven parameters include spatial rectangular coordinate translation ( ), rotation angle ( and scale parameters , among which | |、| |、| | is a random number less than 300m, | |、| |、| | is a random number less than 3 seconds, and the scale parameter k satisfies: k = 1 + a, |a| < 10 × 10 -6 ; S7: Based on the user information, generate and associate a set of paired virtual conversion parameters, which include the virtual plane four parameters generated in step S3 and the virtual seven parameters generated in step S6; the user information includes unit information, registration account, hardware code, software dongle or registration code; S8: Based on the CORS service system, the virtual seven parameters and ellipsoid parameters are broadcast to the user via the RTCM protocol, and the user is guided to enter the paired virtual plane four parameters in the GNSS RTK handheld device; S9: Based on the coordinate transformation system, the user-input coordinates are transformed using paired virtual plane four-parameters and virtual seven-parameters, and the results are output in an independent coordinate system.

2. The method for inverse calculation, encryption and release of coordinate conversion parameters of large-rotation-angle independent coordinate systems according to claim 1, characterized in that: Step S2, which calculates the approximate four-parameter plane, includes the following sub-steps: S2.1: Obtain the geodetic coordinates of the corresponding control points. and results of independent coordinate systems B is latitude, L is longitude, a is the north coordinate of the independent coordinate system, b is the east coordinate of the independent coordinate system, and i is the control point number (i=1, 2, 3, ..., n). S2.2: Approximate the central meridian of the independent coordinate system by performing an approximate process, and retain it to the minute. S2.3: Geodetic coordinate system results using control points , according to the approximate central meridian and the approximate central meridian of the independent coordinate system , the high-pass projection is obtained after the high-pass projection ; S2.4: Using the Gaussian projection coordinates after the belt change and results of independent coordinate systems Calculate its four plane parameters according to the four-parameter plane model. ,in There are two translation parameters. For rotation parameters, This is the scale parameter.

3. The method for inverse calculation, encryption, and publication of coordinate transformation parameters in a large rotation angle independent coordinate system as described in claim 1, characterized in that: The inverse calculation process in step S4 includes the following sub-steps: S4.1: Using virtual planar four parameters Constructing a four-parameter conversion model; S4.2: approximately Gauss projection coordinates are obtained by inverse calculation of the model from the independent coordinate system results .

4. The method for inverse calculation, encryption and release of coordinate conversion parameters of large-rotation-angle independent coordinate systems according to claim 2, characterized in that: The coordinate transformation system in step S9 includes the following sub-steps: S9.1: The user enters geodetic coordinates P i (B, L) into spatial rectangular coordinates (X, Y, Z); S9.2: The spatial rectangular coordinates P (X, Y, Z) are converted into P (X1, Y1, Z1) according to the seven parameters random with user information i (X, Y, Z) into P (X1, Y1, Z1) i (X1, Y1, Z1); S9.3: Convert P i (X1, Y1, Z1) to intermediate space Cartesian coordinates P i (X2, Y2, Z2) using virtual seven parameters S9.4: Convert P i (X2, Y2, Z2) into approximate geodetic coordinates P i (B2, L2); S9.5: along an approximately central meridian P i (B2, L2) is projected as a Gauss projection coordinate P i (x2, y2); S9.6: Convert P (x2, y2) to independent coordinate system result P (a, b) using virtual plane four parameters i (x2, y2) to independent coordinate system result P (a, b). i (x2, y2) to independent coordinate system result P (a, b).

5. The method for inverse calculation, encryption and release of coordinate conversion parameters of large-rotation-angle independent coordinate systems according to claim 4, characterized in that: When the user inputs Gaussian plane coordinates, they must first be converted to geodetic coordinates according to the approximate central meridian, and then sub-steps S9.1 to S9.6 are executed; wherein, the Gaussian plane coordinates are generated based on the approximate central meridian.

6. The method for inverse calculation, encryption and release of coordinate conversion parameters of large-rotation-angle independent coordinate systems according to claim 1, characterized in that: The CORS service system publishing process in step S8 specifically includes: S8.1 The virtual seven parameters and ellipsoid parameters are broadcast to the user's GNSS equipment in real time via the message type of the RTCM protocol; S8.2 Embed a user identity verification identifier in the broadcast data stream, which is associated with the user information in step S7; S8.3 The user's GNSS RTK handheld device automatically parses the virtual seven parameters in the RTCM data stream and triggers the virtual plane four-parameter input guide interface; S8.4 After the user enters the paired virtual plane four parameters according to the guidance, the handheld device integrates the virtual seven parameters broadcast by the RTCM with the locally entered virtual plane four parameters in real time to achieve real-time dynamic positioning in an independent coordinate system.

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