A coordinate transformation method based on server-side pre-transformation and user-side compensation transformation
By using server-side pre-transformation and user-side compensation transformation, coordinate jumps in RTK broadcast services are decomposed and compensated, solving the problems of coordinate stability and parameter confidentiality in real-time RTK broadcasting, and achieving high-precision and stable coordinate transformation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN UNIV
- Filing Date
- 2026-05-29
- Publication Date
- 2026-06-30
AI Technical Summary
In existing technologies for real-time RTK broadcast services, directly applying complete conversion parameters to the reference station coordinates can easily lead to excessive coordinate changes, affecting stability. Furthermore, providing these parameters directly to the user end is detrimental to parameter confidentiality and compliance requirements.
The method of server-side pre-transformation and user-side compensation transformation is adopted. The pre-transformation is performed through the first parameter set, which decomposes the large coordinate jump caused by the complete transformation parameters into controlled small pre-transformations. The intermediate coordinates are then compensated through the second parameter set, so that the final coordinates of the user end are consistent with the original transformation result or within the preset error range, thus maintaining coordinate accuracy and service stability.
It reduces the impact of abnormal reference station coordinate offsets on the stability of RTK ambiguity fixation, balances final coordinate accuracy and real-time service stability, and meets parameter confidentiality and compliance requirements. It is suitable for high-altitude, large-scale network RTK service areas and areas with elevated projection surfaces.
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Figure CN122307616A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of differential positioning service technology, specifically relating to a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation. Background Technology
[0002] Real-time RTK services typically broadcast reference station coordinates, observation correction information, or differential corrections to the user terminal via physical or virtual reference stations. The user terminal then uses this information to resolve ambiguities and output coordinate results. In practical engineering, it is often necessary to convert source coordinate system coordinates to target coordinate system coordinates to meet the requirements of regional coordinate result output, engineering construction layout, local coordinate measurement, and management.
[0003] Existing publicly available technologies mainly revolve around two approaches: First, the server directly uses complete transformation parameters to perform a comprehensive transformation of the reference station coordinates or virtual reference station coordinates before broadcasting; second, the parameters that can be directly used for coordinate frame transformation, either as a whole or in variant form, are sent to the user terminal, which then completes the coordinate result transformation. The former approach is prone to causing significant deviations in the broadcasted reference station coordinate results in specific regions, while the latter is more likely to violate parameter confidentiality and compliance boundaries.
[0004] Patent application CN107193966A discloses a scheme for real-time conversion of virtual reference station ITRF coordinates to WGS84 or CGCS2000 coordinates on the NtripCaster side before broadcasting. The core technical approach of this scheme is for the server to directly perform a complete frame conversion on the virtual reference station coordinates and output the result. However, in large areas, high-altitude areas, or areas with elevated projection surfaces, if the coordinate changes caused by the complete conversion parameters are significant, the broadcast reference station coordinates will deviate significantly relative to the original reference frame, thus affecting the stability of RTK ambiguity fixation and positioning accuracy at the user end.
[0005] Chinese patent CN103235319A discloses a scheme for real-time acquisition of geocentric coordinates and normal elevation via network RTK by setting up an NtripProxy between the NtripCaster and the rover, introducing an auxiliary coordinate system, and configuring seven parameters. While this scheme considers real-time coordinate transformation, its technical approach still relies on the direct configuration and use of transformation parameters. When the complete parameters directly affect the service link or when parameters that can directly participate in the transformation need to be provided to the terminal side, it is still difficult to simultaneously satisfy the constraints of "controlled change in reference station coordinates" and "complete parameters not being publicly disclosed."
[0006] Existing technologies have proposed organizational structures and coordinate return mechanisms for online coordinate transformation service systems. Their typical application mode involves online transformation of measured coordinates followed by return to the user, making them more suitable for post-measurement coordinate transformation or non-real-time coordinate processing scenarios. However, they do not propose a phased suppression scheme to address the impact of sudden changes in reference station coordinates on ambiguity fixation during real-time RTK broadcasting. On the other hand, a technical approach of providing real-time local coordinate results after modifying reference station coordinates on the server side has been proposed. This approach reduces the processing burden on the user end, but it still relies on the idea of modifying the reference station coordinates entirely on the server side before broadcasting. Under conditions of large coordinate differences between corresponding points, long baselines, large rotation parameters, large scale parameters, significant elevation anomalies, or projected elevation, the overall change in reference station coordinates may still affect the reliability of RTK fixation. Furthermore, while multi-coordinate frame transformation and multi-sensor positioning fusion have been studied, their focus is on coordinate frame unification and navigation solution fusion, without addressing the dual constraint of ensuring complete confidentiality of transformation parameters while avoiding significant shifts in broadcast reference station coordinates during real-time RTK broadcasting services.
[0007] Therefore, existing technologies lack a coordinate transformation scheme that can directly address the real-time RTK broadcast service process, without disclosing the original complete transformation parameters to the user end, and simultaneously ensure parameter confidentiality, broadcast reference station coordinate stability, and the final coordinate accuracy of the user end through phased transformation. Summary of the Invention
[0008] To overcome the problems in existing technologies, where directly applying complete transformation parameters to reference station coordinates on the server side can easily cause excessive changes in reference station coordinates, affecting the stability of real-time RTK, and that directly providing complete transformation parameters to the user side is not conducive to meeting parameter confidentiality and compliance requirements, this invention provides a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation. Pre-transformation is performed using a first parameter set to decompose the large coordinate jumps caused by directly applying complete transformation parameters to reference station coordinates into controlled small-scale pre-transformations. A second parameter set compensates for the intermediate coordinates after the first-stage pre-transformation, ensuring that the final coordinates on the user side are consistent with or within a preset error range of the result directly transformed using the original complete transformation parameters P, thus balancing final coordinate accuracy and real-time service stability. The original complete transformation parameters are always kept in a controlled environment on the server side and are not disclosed to the user side. The user side only obtains the second parameter set B or the compensation data derived from it, satisfying parameter confidentiality and compliance requirements.
[0009] According to one aspect of this specification, a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation is provided, applied to a real-time RTK broadcast service system, comprising:
[0010] The server receives the reference station coordinates in the source coordinate system and saves the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system.
[0011] Based on the control rules for changes in reference station coordinates, the first parameter set is constructed from the original complete transformation parameters;
[0012] The first-stage pre-transformation of the coordinates of all reference stations within the service area is performed using the first parameter set to obtain intermediate broadcast coordinates, and real-time dynamic positioning and broadcasting data is generated based on the intermediate broadcast coordinates.
[0013] Select control points, pre-transform the control points using the first parameter set, and transform them using the original complete transformation parameters. Solve for the second parameter set based on the transformation results of the control points.
[0014] The user terminal receives real-time dynamic positioning broadcast data and performs real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.
[0015] As a further technical solution, the first parameter set is generated by constraints on the original complete transformation parameters, including at least one of rotation parameters, translation parameters, and scale parameters.
[0016] As a further technical solution, the original complete conversion parameters are always retained on the server or in a server-controlled environment.
[0017] As a further technical solution, the reference station coordinate change control rule includes at least one of the following:
[0018] After the first stage of pre-transformation, the displacement of any reference station coordinate does not exceed a preset threshold; the coordinates of all reference stations within the service area are directly transformed using the original complete transformation parameters, and the maximum displacement of the reference station coordinates after the first stage of pre-transformation is less than the maximum displacement of the reference station coordinates after direct transformation; and the total displacement of all reference station coordinates within the service area is minimized after the first stage of pre-transformation.
[0019] As a further technical solution, control points cover the service area and / or the target application area.
[0020] As a further technical solution, the control point can be one or more of the following: geodetic control point, known high-precision benchmark point, engineering control network point, calibration point, or check point.
[0021] As a further technical solution, the process of solving the second parameter set based on the transformation and conversion results of the control points includes:
[0022] The intermediate coordinates of the control point are obtained by pre-transforming the transformation point using the first parameter set, and the target coordinates of the control point are obtained by transforming the control point using the original complete transformation parameters.
[0023] Using the intermediate coordinates of the control points as source data and the target coordinates of the control points as target data, the compensation parameter set that transforms the source data into the target data is calculated in reverse and used as the second parameter set.
[0024] As a further technical solution, the second parameter set is solved by inverse calculation using any one of the following: spatial similarity transformation model, partition compensation model, grid correction model, and polynomial compensation model.
[0025] As a further technical solution, the first parameter set and the second parameter set satisfy:
[0026] For any reference station coordinates to be transformed , and Consistent within a preset error threshold, wherein, This represents the first-stage pretransformation operator defined by the first parameter set A; This represents the second-stage compensation transformation operator defined by the second parameter set B; This represents a direct transformation operator defined by the original complete transformation parameter P.
[0027] According to another aspect of this specification, a coordinate transformation system based on server-side pre-transformation and user-side compensation transformation is provided to implement a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation, comprising:
[0028] The server-side parameter management module is used to receive reference station coordinates in the source coordinate system and save the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system; it is also used to construct a first parameter set from the original complete transformation parameters according to the control rules of the change in reference station coordinates.
[0029] The server-side pre-transformation module is used to perform a first-stage pre-transformation on the coordinates of all reference stations within the service area using the first parameter set to obtain intermediate broadcast coordinates.
[0030] The broadcast module is used to generate real-time dynamic positioning and broadcast data based on intermediate broadcast coordinates;
[0031] The compensation parameter generation module is used to select control points, pre-transform the control points using the first parameter set, and transform them using the original complete transformation parameters. The second parameter set is then solved based on the transformation results of the control points and the transformation results.
[0032] The user-side compensation module is used to receive real-time dynamic positioning broadcast data and perform real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.
[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention uses the first parameter set A to perform pre-transformation on the server side, decomposes the large jump in coordinates caused by the direct application of the complete transformation parameters to the reference station coordinates into a controlled small amount of pre-transformation, thereby reducing the impact of abnormal offset of broadcast reference station coordinates on the fixed stability of RTK ambiguity.
[0034] (2) The present invention compensates the intermediate coordinates after the first stage pre-transformation by the second parameter set B, so that the final coordinates of the user terminal can be consistent with the result of direct transformation of the original complete transformation parameter P or within the preset error range, thereby taking into account both the accuracy of the final coordinates and the stability of real-time service.
[0035] (3) In this invention, the original complete conversion parameter P is always kept in the server-side controlled environment and is not disclosed to the user. The user only obtains the second parameter set B or the compensation data derived from it, which helps to meet the requirements of parameter confidentiality and compliance.
[0036] (4) This invention is particularly applicable to high-altitude areas, large-scale network RTK service areas, areas with elevated projection surfaces, and scenarios where fixed performance is reduced due to the direct effect of complete parameters on the reference station coordinates. It has strong engineering applicability. Attached Figure Description
[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0038] Figure 1 This is a flowchart illustrating a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation provided in an embodiment of the present invention.
[0039] Figure 2 This is a schematic diagram of the overall architecture of the coordinate transformation method in an embodiment of the present invention;
[0040] Figure 3 This is a schematic diagram of a coordinate transformation system based on server-side pre-transformation and user-side compensation transformation, provided as an embodiment of the present invention. Detailed Implementation
[0041] It should be noted that:
[0042] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0043] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0045] like Figure 1 As shown, this invention discloses a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation, applied to a real-time RTK broadcast service system, comprising:
[0046] Step 1: Receive the reference station coordinates in the source coordinate system and save the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system.
[0047] Step 2: Based on the control rules for changes in reference station coordinates, construct the first parameter set from the original complete transformation parameters;
[0048] Step 3: Perform the first-stage pre-transformation on the coordinates of all reference stations within the service area using the first parameter set to obtain intermediate broadcast coordinates, and generate real-time dynamic positioning broadcast data based on the intermediate broadcast coordinates;
[0049] Step 4: Select control points, pre-transform the control points using the first parameter set to obtain the intermediate coordinates of the control points, and then transform the control points using the original complete transformation parameters to obtain the target coordinates of the control points. Solve for the transformation parameter set that transforms the intermediate coordinates of the control points to the target coordinates of the control points, and use it as the second parameter set.
[0050] Step 5: The user terminal receives the real-time dynamic positioning broadcast data and performs real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.
[0051] The method of this invention is applicable to any one or more of CORS networks, network RTK services, virtual reference station (VRS) services, and single-base station RTK services. The real-time RTK broadcast service system employed includes a server and a user terminal.
[0052] The server is used for parameter management, reference station management, virtual reference station generation, first parameter set A generation, broadcasting, and second parameter set generation.
[0053] The user-side component is used for RTK computation, parameter reception, and compensation transformation.
[0054] In step 1, the firstly, the reference station coordinates are physical reference station coordinates and / or virtual reference station coordinates.
[0055] Secondly, the original complete transformation parameters are used to transform the coordinates of the source coordinate system to the coordinates of the target coordinate system and are stored in the controlled environment of the server.
[0056] For example, the original complete transformation parameter P can be a seven-parameter parameter, an equivalent spatial similarity transformation parameter, a three-dimensional coordinate transformation parameter with a scale term and a rotation term, or other rigorous transformation parameters that can transform the source coordinate system coordinates to the target coordinate system coordinates.
[0057] It should be emphasized that in the method provided by this invention, the original complete conversion parameters P are always retained on the server or in a controlled environment.
[0058] In step 2, the first rule for controlling the change in reference station coordinates includes at least one of the following:
[0059] After the first stage of pre-transformation, the displacement of any reference station coordinate is not greater than a preset threshold; after the first stage of pre-transformation, the maximum displacement of the reference station coordinate within the service area is less than the maximum displacement of the reference station coordinate within the service area after directly transforming all reference station coordinates within the service area using the original complete transformation parameters; and after the first stage of pre-transformation, the total displacement of all reference station coordinates within the service area is minimized.
[0060] Secondly, the first parameter set A is generated from the original complete transformation parameter constraints, including at least one of the following: rotation parameters, translation parameters, and scaling parameters:
[0061] The first parameter set A consists of some constrained components of the original complete transformation parameter P.
[0062] Alternatively, the first parameter set A can also be generated from the original complete transformation parameters P through scaling, optimization, iteration, etc.
[0063] Specifically, the first parameter set A is used to control the displacement of the reference station coordinates broadcast by the server, so that the reference station coordinates after the first stage pre-transformation are kept within a controlled range that is conducive to the fixed stability of the real-time dynamic position (RTK).
[0064] The first parameter set A is constructed from the original complete transformation parameters according to the control rules for the change in reference station coordinates. Specifically, the control rules for the change in reference station coordinates include at least one of the following:
[0065] After the first stage of pre-transformation, the displacement of any reference station coordinate does not exceed a preset threshold; the coordinates of all reference stations within the service area are directly transformed using the original complete transformation parameters, and the maximum displacement of the reference station coordinates after the first stage of pre-transformation is less than the maximum displacement of the reference station coordinates after direct transformation; and the total displacement of all reference station coordinates within the service area is minimized after the first stage of pre-transformation.
[0066] As an optional implementation, the server uses a set of reference stations within the service area. The first parameter set A is constructed by minimizing the change in reference station coordinates, while ensuring that the displacement of any reference station coordinate after transformation by the first parameter set A does not exceed a threshold D. The first parameter set A is solved by either minimizing the maximum displacement or minimizing the overall displacement, so that the intermediate broadcast coordinates are as close as possible to the unmodified reference station coordinate frame.
[0067] In step 3, after obtaining the first parameter set A, the server performs a first-stage pre-transformation on the physical reference station coordinates or virtual reference station coordinates to obtain intermediate broadcast coordinates. If a single base station mode is used, the intermediate broadcast coordinates are used as base station coordinates to generate the corresponding real-time broadcast data. Optionally, if a VRS (virtual reference station) mode is used, the intermediate broadcast coordinates are used as virtual reference station coordinates to participate in RTCM message organization and differential correction generation to generate real-time broadcast data.
[0068] In step 3, the real-time broadcast data includes at least one of the following: physical reference station coordinates, virtual reference station coordinates, RTCM messages, observation correction information, and differential corrections.
[0069] In step 4, the control points cover the service area and / or the target application area, and can be one or more of the following: geodetic control points, known high-precision reference points, engineering control network points, calibration points, or check points.
[0070] Furthermore, the process of solving for the second parameter set B based on the transformation and conversion results of the control points includes:
[0071] The intermediate coordinates of the control point are obtained by pre-transforming the transformation point using the first parameter set, and the target coordinates of the control point are obtained by transforming the control point using the original complete transformation parameters.
[0072] Using the intermediate coordinates of the control points as source data and the target coordinates of the control points as target data, the compensation parameter set that transforms the source data into the target data is calculated in reverse and used as the second parameter set.
[0073] The second parameter set is solved by inverse calculation using any one of the following models: spatial similarity transformation model, partition compensation model, grid correction model, and polynomial compensation model.
[0074] As a specific implementation process, the second parameter set B in step 4 is calculated based on the control point coordinates. Specifically:
[0075] 4-1. Select multiple control points:
[0076] Let the set of control points be ,in, Indicates the j-th control point;
[0077] 4-2. Obtain intermediate coordinates by pre-transforming the control points using the first parameter set A; and further transform the control points using the original complete transformation parameters (P) to obtain the target coordinates:
[0078] The server calculates separately:
[0079] , ;
[0080] In the formula, This represents the first-stage pretransformation operator defined by the first parameter set A; This represents a direct transformation operator defined by the original complete transformation parameter P, which represents a direct transformation that transforms the coordinates of the source coordinate system to the coordinates of the target coordinate system. This represents the intermediate coordinates of the j-th control point; This represents the target coordinates of the j-th control point.
[0081] 4-3. Using the intermediate coordinates of the control points as the source and the target coordinates of the control points as the objective, solve for the second parameter set B:
[0082] by As the source coordinate set, with Given the target coordinate set, the second parameter set B is obtained by solving using a spatial similarity transformation model, a partition compensation model, a mesh correction model, or a polynomial compensation model.
[0083] It should be added here that: the second parameter set It describes the compensation relationship from the intermediate coordinates of the control point to the target coordinates of the control point, rather than the original complete transformation parameter P itself.
[0084] In a preferred embodiment, when the number and distribution of control points meet the solution conditions of the spatial similarity transformation model, the least squares method can be used to solve the second parameter set B; when the service area spans a large area, the terrain undulations are significant, or the projection distortion distribution is uneven, the second parameter set B can also be constructed according to the region, projection zone, or elevation zone to improve the accuracy of local compensation.
[0085] As a supplementary explanation, the second parameter set B is constructed according to region, projection zone, elevation zone or service type, and corresponds to the first parameter set A currently used by the server in a version management manner.
[0086] The second parameter set B is used to compensate for the difference between the first-stage pre-transformation through the first parameter set A and the direct transformation through the original complete transformation parameters P, that is:
[0087] The first parameter set and the second parameter set satisfy:
[0088] For any reference station coordinates to be transformed ,satisfy: and Consistent within a preset error threshold, wherein, This represents the first-stage pre-transform operator defined by the first parameter set A, and signifies the first-stage transformation. This represents the second-stage compensation transformation operator defined by the second parameter set B, and signifies the second-stage compensation transformation.
[0089] Preferably, any reference station coordinate point to be converted Satisfying the equation .
[0090] In a preferred embodiment, for parameter security, a method for updating the first parameter set A and the second parameter set B is provided: the second parameter set B can be periodically updated by the server and then distributed to authorized users through a secure channel, or it can be distributed differently according to region, permission, or service type. When a service area experiences a baseline update, control point recalculation, or parameter re-evaluation, the server regenerates the first parameter set A and the second parameter set B, and ensures through a version management mechanism that the compensation parameters used by the user are consistent with the current pre-transformation parameters on the server.
[0091] It should be noted that the specific representations of the first parameter set A and the second parameter set B are not limited to the seven-parameter expression. As long as the technical effect of the server performing controlled pre-transformation of the broadcast reference station coordinates and the user terminal compensating for intermediate coordinates and obtaining the target coordinates can be achieved, it should fall within the protection scope of this invention.
[0092] In step 5, the user terminal receives the second parameter set B (or compensation data) through a secure channel. The original complete transformation parameters P are always retained on the server or in a server-controlled environment. RTK ambiguity is fixed by performing real-time dynamic positioning calculations, and then a second-stage compensation transformation is performed on the fixed calculated coordinates.
[0093] As a specific implementation method, step 5, the step of performing the second-stage compensation transformation, includes:
[0094] After receiving the RTK broadcast data generated based on the first parameter set A, the user terminal performs RTK calculations within the reference frame corresponding to the intermediate broadcast coordinates. Preferably, the user terminal performs the calculations after the ambiguity is fixed and the intermediate coordinates are obtained. Then execute This outputs the final coordinates in the target coordinate system. .
[0095] In other alternative implementations, the second-stage compensation transformation can also be performed in the floating-point solution stage, coordinate output stage, or post-processing stage, and can be applied to the floating-point solution coordinates, the intermediate positioning coordinates of the user terminal, or the observation correction information corresponding to the positioning coordinates of the user terminal.
[0096] As an optional implementation method, such as Figure 2 As shown, the coordinate transformation method in this invention includes:
[0097] S1. Obtain the coordinates of the entity reference station and / or the virtual reference station in the source coordinate system, and save the original complete transformation parameters P used to transform the source coordinate system coordinates to the target coordinate system coordinates in the server-side controlled environment;
[0098] S2. According to the rule of controlled change of reference station coordinates, construct the first parameter set A from the original complete transformation parameter P to control the change of coordinates of the physical reference station and / or the virtual reference station after transformation by the first parameter set A.
[0099] S3. The server uses the first parameter set A to perform the first-stage pre-transformation on the coordinates of the physical reference station and / or the virtual reference station to obtain the intermediate broadcast coordinates, and generates real-time RTK broadcast data based on the intermediate broadcast coordinates.
[0100] S4. Select control points, transform the control points through the first parameter set A to obtain intermediate coordinates, transform the same control points through the original complete transformation parameter P to obtain target coordinates, and solve the second parameter set B with the intermediate coordinates as the source and the target coordinates as the target.
[0101] S5. Provide the user with the second parameter set B or the compensation data generated based on the second parameter set B, without disclosing the original complete conversion parameter P to the user.
[0102] S6. The user terminal completes RTK calculation based on the real-time RTK broadcast data, and performs a second-stage compensation transformation on the intermediate coordinates obtained from the RTK calculation according to the second parameter set B to obtain the final coordinates in the target coordinate system.
[0103] The implementation of the various embodiments of the present invention is based on programmed processing through a system with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a coordinate transformation system based on server-side pre-transformation and user-side compensation transformation. This system is used to execute a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation from the above method embodiments.
[0104] See Figure 3 The system includes:
[0105] The server-side parameter management module is used to receive reference station coordinates in the source coordinate system and save the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system; it is also used to construct a first parameter set from the original complete transformation parameters according to the control rules of the change in reference station coordinates.
[0106] The server-side pre-transformation module is used to perform a first-stage pre-transformation on the coordinates of all reference stations within the service area using the first parameter set to obtain intermediate broadcast coordinates.
[0107] The broadcast module is used to generate real-time dynamic positioning and broadcast data based on intermediate broadcast coordinates;
[0108] The compensation parameter generation module is used to select control points, pre-transform the control points using the first parameter set, and transform them using the original complete transformation parameters. The second parameter set is then solved based on the transformation results of the control points and the transformation results.
[0109] The user-side compensation module is used to receive real-time dynamic positioning broadcast data and perform real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.
[0110] It should be noted that the system embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above system embodiments provided by the present invention. As long as those skilled in the art can improve the modules in the above system embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above system embodiments, and on the premise of ensuring the practicality of the technical solutions, they can obtain corresponding system-like embodiments for implementing the methods in other method-like embodiments.
[0111] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, located in one place, or distributed across multiple network units. The purpose of this embodiment is achieved by selecting some or all of the modules according to actual needs. Those skilled in the art will understand and implement this without any inventive effort.
[0112] In summary, this invention discloses a coordinate transformation method based on server-side pre-transformation and user-side compensation transformation, applied to the real-time RTK broadcast service process. The server stores the original complete transformation parameters P, constructs a first parameter set A, and performs a pre-transformation on the coordinates of physical reference stations and / or virtual reference stations to generate intermediate broadcast coordinates or corresponding broadcast data. Then, based on the intermediate coordinates obtained by transforming control points through the first parameter set A and the target coordinates obtained by transforming through the original complete transformation parameters P, a second parameter set B is solved. Without obtaining the original complete transformation parameters P, the user terminal performs a compensation transformation on the intermediate coordinates obtained from the RTK solution based on the second parameter set B to obtain the final coordinates in the target coordinate system. This invention balances parameter confidentiality, RTK stability, and coordinate accuracy, and is suitable for high-altitude areas, large-scale network RTK service areas, and areas with elevated projection surfaces.
[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.
Claims
1. A coordinate transformation method based on server-side pre-transformation and user-side compensation transformation, characterized in that, Applications include real-time RTK broadcast service systems, including: The server receives the reference station coordinates in the source coordinate system and saves the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system. Based on the control rules for changes in reference station coordinates, the first parameter set is constructed from the original complete transformation parameters; The first-stage pre-transformation of the coordinates of all reference stations within the service area is performed using the first parameter set to obtain intermediate broadcast coordinates, and real-time dynamic positioning and broadcasting data is generated based on the intermediate broadcast coordinates. Select control points, pre-transform the control points using the first parameter set, and transform them using the original complete transformation parameters. Solve for the second parameter set based on the transformation results of the control points. The user terminal receives real-time dynamic positioning broadcast data and performs real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.
2. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The first parameter set is generated from the original complete transformation parameter constraints, including at least one of rotation parameters, translation parameters, and scale parameters.
3. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The original complete conversion parameters are always retained on the server or in a server-controlled environment.
4. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The control rules for the change in reference station coordinates include at least one of the following: After the first stage of pre-transformation, the displacement of any reference station coordinate is not greater than the preset threshold; the coordinates of all reference stations in the service area are directly transformed using the original complete transformation parameters, and the maximum displacement of the reference station coordinates after the first stage of pre-transformation is less than the maximum displacement of the reference station coordinates after direct transformation. And after the first stage of pre-transformation, the total displacement of all reference station coordinates within the service area is minimized.
5. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The control points cover the service area and / or the target application area.
6. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The control point is one or more of the following: a geodetic control point, a known high-precision benchmark point, an engineering control network point, a calibration point, or a check point.
7. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 1, characterized in that, The process of solving for the second parameter set based on the transformation and conversion results of the control points includes: The intermediate coordinates of the control point are obtained by pre-transforming the transformation point using the first parameter set, and the target coordinates of the control point are obtained by transforming the control point using the original complete transformation parameters. Using the intermediate coordinates of the control points as source data and the target coordinates of the control points as target data, the compensation parameter set that transforms the source data into the target data is calculated in reverse and used as the second parameter set.
8. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 7, characterized in that, The second parameter set is solved by inverse calculation using any one of the following models: spatial similarity transformation model, partition compensation model, grid correction model, and polynomial compensation model.
9. The coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in claim 8, characterized in that, The first parameter set and the second parameter set satisfy: For any reference station coordinates to be transformed , and Consistent within a preset error threshold, wherein, This represents the first-stage pretransformation operator defined by the first parameter set A; This represents the second-stage compensation transformation operator defined by the second parameter set B; This represents a direct transformation operator defined by the original complete transformation parameter P.
10. A coordinate transformation system based on server-side pre-transformation and user-side compensation transformation, used to implement the coordinate transformation method based on server-side pre-transformation and user-side compensation transformation as described in any one of claims 1 to 9, characterized in that, include: The server-side parameter management module is used to receive reference station coordinates in the source coordinate system and save the original complete transformation parameters; the original complete transformation parameters are used to transform the coordinates in the source coordinate system to the coordinates in the target coordinate system; it is also used to construct a first parameter set from the original complete transformation parameters according to the control rules of the change in reference station coordinates. The server-side pre-transformation module is used to perform a first-stage pre-transformation on the coordinates of all reference stations within the service area using the first parameter set to obtain intermediate broadcast coordinates. The broadcast module is used to generate real-time dynamic positioning broadcast data based on intermediate broadcast coordinates; The compensation parameter generation module is used to select control points, pre-transform the control points using the first parameter set, and transform them using the original complete transformation parameters. The second parameter set is then solved based on the transformation results of the control points and the transformation results. The user-side compensation module is used to receive real-time dynamic positioning broadcast data and perform real-time dynamic positioning calculation. Based on the second parameter set, it performs a second-stage compensation transformation on the intermediate coordinates obtained from the real-time dynamic positioning calculation to obtain the final coordinates in the target coordinate system.