Coordinate determination method and device

Abstract

The invention belongs to the technical field of position positioning, and discloses a coordinate determination method and device. According to the method, when the target coordinate information of the target track point is determined, calculation efficiency and real-time performance are improved by simplifying operation and reducing iteration, coordinate precision and rationality are guaranteed through targeted curvature compensation and terrain clearance correction, the problem that efficiency and precision are difficult to consider in a traditional method is solved, and the method is suitable for large-scale popularization and application. And the coordinate determination requirement of the high-frequency dynamic target track can be met.

Description

Technical Field

[0001] This application relates to the field of location positioning technology, and in particular to a method and apparatus for determining coordinates. Background Technology

[0002] In existing technologies, determining the coordinates of trajectory points typically relies on geospatial migration using the WGS84 coordinate system. Specifically, this involves converting the geographic coordinates of trajectory points in the trajectory to be processed into geocentric-fixed (ECEF) coordinates, performing a global affine transformation on these ECEF coordinates, and then using an iterative algorithm to inversely transform the transformed ECEF coordinates back to WGS84 geographic coordinates. Finally, this is combined with a digital elevation model (DEM) for terrain adaptation to determine the trajectory point coordinates. However, this method has significant drawbacks: firstly, it does not use the ENU coordinate system with the first trajectory point as the origin. The coordinate transformation process involves complex ellipsoidal calculations (such as trigonometric functions, square roots, and other transcendental functions) and iterative operations (such as ECEF). First, the inverse conversion between ECEF and WGS84 results in extremely low computational efficiency and insufficient real-time performance when acquiring the coordinates of target trajectory points in the trajectory to be processed, making it difficult to quickly obtain the coordinates of the target trajectory points. Second, when performing large-scale displacement processing, the accuracy of trajectory point coordinates will significantly decrease due to the curvature of the Earth. Although it can be corrected by curvature compensation, traditional curvature compensation requires additional iteration or high-order expansion, further increasing the computational burden. Moreover, it is impossible to perform targeted compensation based on the displacement distance between the coordinates of the target trajectory point and the origin (i.e., the distance between the trajectory point and the starting point of the trajectory to be processed), making it difficult to balance accuracy and efficiency. Third, the terrain adaptation process requires frequent calls to the inverse conversion between ECEF and WGS84. This process competes with DEM data access for resources, and the coordinates are not efficiently corrected based on the ground clearance of the target trajectory point. As a result, the final acquired trajectory point coordinates are difficult to balance in terms of efficiency and accuracy, and cannot meet the need for quickly and accurately determining the coordinates of target trajectory points in the trajectory to be processed. Summary of the Invention

[0003] This application provides a coordinate determination method and apparatus, which can effectively solve the problem that existing methods cannot balance efficiency and accuracy.

[0004] Firstly, this application provides a coordinate determination method, the method comprising: Obtain the ENU coordinate system corresponding to the trajectory to be processed; wherein, the origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed; Obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. Based on the displacement distance corresponding to the second coordinate information, curvature compensation is performed on the second coordinate information to obtain the compensated second coordinate information; wherein, the displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system; The compensated second coordinate information is transformed to obtain the geographic coordinate information corresponding to the compensated second coordinate information. Based on the ground clearance of the target trajectory point, the geographic coordinate information corresponding to the compensated second coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

[0005] Secondly, this application provides a coordinate determining device, the device comprising: The first unit is used to obtain the ENU coordinate system corresponding to the trajectory to be processed; wherein the origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed; The second unit is used to obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and to perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. The third unit is used to perform curvature compensation on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information; wherein, the displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system; The fourth unit is used to perform coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information; The fifth unit is used to correct the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point, so as to obtain the target coordinate information of the target trajectory point.

[0006] Thirdly, this application provides a readable medium including executable instructions, which, when executed by a processor of an electronic device, cause the electronic device to perform any of the methods described in the first aspect.

[0007] Fourthly, this application provides an electronic device including a processor and a memory storing execution instructions, wherein when the processor executes the execution instructions stored in the memory, the processor performs the method as described in any of the first aspects.

[0008] As can be seen from the above technical solution, this application has the following beneficial effects compared with the prior art: This coordinate determination method significantly improves the efficiency and accuracy of determining the coordinates of target trajectory points in the trajectory to be processed through the synergistic effect of the following steps: First, the origin of the ENU coordinate system is set as the first trajectory point of the trajectory to be processed, ensuring strict alignment between the trajectory and the ENU coordinate system. This avoids the complex ellipsoidal coordinate transformation under the traditional WGS84 coordinate system, enabling rapid acquisition of the first coordinate information of the target trajectory point in the ENU coordinate system and simplifying the initial coordinate acquisition process. Second, the first coordinate information is directly subjected to an affine transformation to obtain the second coordinate information, without the need to first transform the coordinates to the ECEF coordinate system. Compared with the traditional global affine transformation, this significantly reduces intermediate calculation steps and improves the coordinate transformation speed. Third, based on the second coordinate information and the ENU coordinate system... The displacement distance of the coordinate system origin is used to perform curvature compensation on the second coordinate information, which can be specifically adapted to different displacement distance scenarios (e.g., no compensation is needed when the displacement distance is small, first-order approximation compensation is used for medium distances, and second-order approximation compensation is used for large distances), avoiding the additional iterative burden of traditional curvature compensation and reducing the amount of computation while ensuring coordinate accuracy. Then, the compensated second coordinate information is converted into geographic coordinate information. This conversion process is a simple analytical calculation without iteration, which further shortens the coordinate conversion time compared to the inverse conversion of traditional ECEF and WGS84. Finally, the geographic coordinate information is corrected according to the ground clearance of the target trajectory point, which can effectively avoid unreasonable situations such as "drilling" or "suspending", ensuring that the target coordinate information of the target trajectory point is reasonable. In summary, the whole method improves the computational efficiency and real-time performance by simplifying the calculation and reducing iterations when determining the target coordinate information of the target trajectory point, and ensures the accuracy and reasonableness of the coordinates through targeted curvature compensation and ground clearance correction. It solves the problem that traditional methods are difficult to balance efficiency and accuracy, and can meet the coordinate determination requirements of high-frequency dynamic target trajectories.

[0009] The further effects of the aforementioned non-conventional preferred method will be explained below in conjunction with specific embodiments. Attached Figure Description

[0010] To more clearly illustrate the embodiments of this application or the existing technical solutions, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating a coordinate determination method provided in this application; Figure 2 A flowchart illustrating a coordinate determination method provided in this application; Figure 3 A schematic diagram of the structure of a coordinate determining device provided in this application; Figure 4 This is a schematic diagram of the structure of an electronic device provided in this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] The various non-limiting embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0014] See details Figure 1 This paper illustrates a coordinate determination method according to an embodiment of the present application, the method comprising: S101: Obtain the ENU coordinate system corresponding to the trajectory to be processed.

[0015] The origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed.

[0016] The trajectory to be processed refers to the target motion trajectory that needs to be determined and corrected in terms of coordinates. It includes multiple trajectory points arranged in time or space order (such as the three-dimensional motion trajectory of a high-speed maneuvering target, the path trajectory of a cluster of equipment, etc.).

[0017] The target trajectory point refers to a single trajectory point in the trajectory to be processed that requires the determination of the final target coordinate information, and it is the core processing object of this method.

[0018] The ENU coordinate system refers to the East-North-Sky coordinate system. It is a Cartesian coordinate system with a specific reference point as the origin and the three coordinate axes pointing east (E axis, corresponding to the horizontal eastward direction), north (N axis, corresponding to the horizontal northward direction), and zenith (U axis, corresponding to the vertical upward direction). Its characteristic is that it can approximate the Earth's surface as a plane in local areas, simplifying coordinate calculations.

[0019] In this embodiment, the geographic coordinates of the first trajectory point of the trajectory to be processed can be obtained first. Then, the geographic coordinates of the first trajectory point can be converted into the first coordinates of the first trajectory point in the ENU coordinate system. Next, the first coordinates of the first trajectory point in the ENU coordinate system can be used as the origin of the ENU coordinate system, and the ENU coordinate system corresponding to the trajectory to be processed can be established.

[0020] It is understandable that the first coordinate information refers to the original coordinates of the trajectory point in the ENU coordinate system without undergoing affine transformation, denoted as (E, N, U), where E is the eastward displacement, N is the northward displacement, and U is the celestial displacement, all in meters.

[0021] In other words, this embodiment needs to establish an ENU coordinate system with the first trajectory point of the trajectory to be processed as the origin, to ensure that the local coordinate calculation is strictly aligned with the initial position of the trajectory to be processed. The specific implementation is as follows: Obtain the geographic coordinates of the first trajectory point: First, collect the geographic coordinate information of the first trajectory point (i.e., the trajectory starting point) of the trajectory to be processed. These geographic coordinates are represented using a conventional geographic coordinate system (such as WGS84 geographic coordinates), denoted as ( ,λ0, h0), where, λ0 represents the latitude of the first trajectory point (in degrees), λ0 represents the longitude of the first trajectory point (in degrees), and h0 represents the elevation of the first trajectory point above the ellipsoid (in meters).

[0022] Next, the geographic coordinates of the first trajectory point will be set to ENU coordinates. Since the ENU coordinate system can approximate the Earth's surface as a plane in local areas (<200km), and 1° of latitude corresponds to approximately 111.32km and 1° of longitude corresponds to approximately 111.32×cosφ0km, the geographic coordinates of the first trajectory point will be set to ENU coordinates using a linear formula. The coordinates of the first trajectory point (λ0, h0) are converted to their coordinates in the ENU coordinate system. However, since the first trajectory point will be used as the origin of the ENU coordinate system, its converted ENU coordinates are theoretically (0, 0, 0). The conversion formula is only used to verify the rationality of the local plane assumption. That is, the geographic coordinate information of the first trajectory point can be converted into the first coordinate information of the first trajectory point in the ENU coordinate system using the following formula, the specific formula is as follows:

[0023] Where E, N, and U are the east, north, and sky coordinates of the first trajectory point in the ENU coordinate system, respectively, in meters; λ represents the latitude of the trajectory point (i.e., the trajectory point whose coordinate information needs to be transformed), λ represents the longitude of the trajectory point (i.e., the trajectory point whose coordinate information needs to be transformed), and h represents the elevation of the trajectory point (i.e., the trajectory point whose coordinate information needs to be transformed). λ0 represents the latitude of the first trajectory point, λ0 represents the longitude of the first trajectory point, and h0 represents the elevation of the first trajectory point; Finally, an ENU coordinate system can be established. That is, the coordinates (0, 0, 0) of the first trajectory point in the ENU coordinate system are taken as the origin of the ENU coordinate system, and the three axes of the coordinate system (east, north, and sky) are determined, thus completing the establishment of the ENU coordinate system corresponding to the trajectory to be processed.

[0024] S102: Obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system.

[0025] In this embodiment, the first coordinate information of the target trajectory point in the trajectory to be processed in the ENU coordinate system can be obtained first. Then, an affine transformation can be performed on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system; as an example, rotation and translation operations can be performed on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. The second coordinate information refers to the coordinates obtained after the first coordinate information of the trajectory point has undergone affine transformation (rotation and translation), denoted as (E', N', U'), and the unit is meters.

[0026] It should be noted that the specific implementation method of this step "obtaining the first coordinate information of the target trajectory point in the ENU coordinate system" is the same as the specific implementation method of the step "converting the geographic coordinate information of the first trajectory point into the first coordinate information of the first trajectory point in the ENU coordinate system" in S101. Please refer to the above relevant descriptions, and it will not be repeated here.

[0027] In other words, after obtaining the first coordinate information of the target trajectory point in the ENU coordinate system, an affine transformation can be performed on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. Specifically, the original coordinates of the target trajectory point in the ENU coordinate system are first obtained, and then the coordinate position is adjusted through rotation and translation operations. The specific implementation is described below: Obtain the first coordinate information of the target trajectory point: For any target trajectory point in the trajectory to be processed, collect its original geographic coordinates (φ, λ, h), where φ is the latitude of the target trajectory point, λ is the longitude, and h is the elevation. Based on the ENU coordinate system established in S101, the geographic coordinates are converted into the first coordinate information (E, N, U) of the target trajectory point in the ENU coordinate system through a linear transformation formula. The transformation formula is the same as the formula in S101.

[0028] Next, an affine transformation is performed on the first coordinate information. The purpose of the affine transformation is to rotate and translate the first coordinate information (E, N, U) according to the spatial migration requirements of the trajectory to be processed (such as the overall translation and rotation adjustment of the target trajectory) to obtain the second coordinate information (E', N', U'). This transformation is implemented through matrix operations, and the specific formula is as follows:

[0029] Where R is the rotation matrix (selected to rotate around the east, north, or celestial axis according to actual needs; for example, R is a 2D rotation matrix when rotating around the celestial axis, and a 3D rotation matrix when rotating around the east or north axis; the specific matrix form is determined according to the rotation angle); ΔE is the eastward translation, ΔN is the northward translation, and ΔU is the celestial translation; all three have values ​​within the range of... It can be preset according to the spatial migration requirements of the trajectory to be processed.

[0030] S103: Based on the displacement distance corresponding to the second coordinate information, perform curvature compensation on the second coordinate information to obtain the compensated second coordinate information.

[0031] The displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system. It can be understood that the displacement distance (D) refers to the Euclidean distance in the horizontal direction (east and north) of the second coordinate information from the origin of the ENU coordinate system, i.e., the straight-line distance calculated considering only E' and N', in meters, used to determine whether curvature compensation is needed and the compensation method.

[0032] In this embodiment, curvature compensation can be performed on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information.

[0033] As an example, the distance between the second coordinate information and the origin of the ENU coordinate system can be used as the displacement distance corresponding to the second coordinate information.

[0034] If the displacement distance corresponding to the second coordinate information is less than or equal to the first preset threshold, the second coordinate information is used as the compensated second coordinate information.

[0035] If the displacement distance corresponding to the second coordinate information is greater than the first preset threshold and less than or equal to the second preset threshold, the second coordinate is subjected to curvature compensation using a first-order approximation compensation method to obtain the compensated second coordinate information.

[0036] If the displacement distance corresponding to the second coordinate information is greater than the second preset threshold, the second coordinate is subjected to curvature compensation using a second-order approximation compensation method to obtain the compensated second coordinate information.

[0037] The first preset threshold refers to the minimum displacement distance that triggers curvature compensation. For example, it can be set to 50km. When the displacement distance is ≤50km, the influence of the Earth's curvature is negligible and no compensation is required.

[0038] The second preset threshold refers to the displacement distance at which the curvature compensation method is switched (from first-order approximate compensation to second-order approximate compensation). For example, it can be set to 200km. When the displacement distance is > 50km and ≤ 200km, first-order approximate compensation is used, and when the displacement distance is > 200km, second-order approximate compensation is used.

[0039] In this embodiment, the compensation method is dynamically selected based on the displacement distance of the target trajectory point. While avoiding the influence of the Earth's curvature, the amount of computation is reduced to the minimum. The specific implementation is as follows: First, calculate the displacement distance corresponding to the second coordinate information. The displacement distance D is the horizontal distance between the second coordinate information (E', N', U') and the origin of the ENU coordinate system (considering only the east and north directions, ignoring the influence of axial displacement on curvature), calculated using the Euclidean distance formula, specifically:

[0040] Where D is the displacement distance in meters, used to determine the degree of influence of the Earth's curvature on coordinate accuracy.

[0041] Then, the curvature compensation method is selected based on the displacement distance. Taking into account the influence of Earth's curvature, the compensation interval is divided using a first preset threshold (e.g., 50km) and a second preset threshold (e.g., 200km). The specific compensation logic is as follows: Figure 2 As shown, specifically: If the displacement distance corresponding to the second coordinate information is less than or equal to the first preset threshold, for example, when the displacement distance D ≤ 50km (the first preset threshold): the influence of the Earth's curvature on the coordinate accuracy is negligible (error < 1 meter), and no curvature compensation is required. The second coordinate information (E', N', U') is directly used as the compensated second coordinate information (E', N', U'). c N c U c ), that is (E c N c U c = (E', N', U').

[0042] If the displacement distance corresponding to the second coordinate information is greater than the first preset threshold and less than or equal to the second preset threshold, for example, when 50km < D ≤ 200km (the second preset threshold), the Earth's curvature begins to have a significant impact (error of 5-15 meters), and a first-order approximate compensation method needs to be used for correction. The compensation formula is as follows (only the east and north coordinates are corrected; the celestial coordinates are not affected by curvature and remain unchanged), that is, the first-order approximate compensation method is as shown in the following formula:

[0043] Where r = 6378137 meters (semi-major axis of the Earth ellipsoid); Semi-major axis of the Earth ellipsoid (r): refers to the semi-major axis parameter in the WGS84 ellipsoid model, with a value of 6378137 meters, used for curvature compensation calculation.

[0044] If the displacement distance corresponding to the second coordinate information is greater than the second preset threshold, for example, when D > 200km: the influence of the Earth's curvature further increases (error > 15 meters), and a second-order approximate compensation method is required to improve accuracy. The compensation formula (i.e., the second-order approximate compensation method) is as follows: .

[0045] Through the above-mentioned graded compensation, the planar error can be controlled to <15 meters and the height error to <5 meters within the second preset threshold (e.g., 200km), thereby achieving higher accuracy.

[0046] S104: Perform coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information.

[0047] The inverse transformation in this scheme can be performed directly through simple analytical calculations without iteration. That is, the coordinate transformation in this step is the inverse transformation corresponding to the transformation formula in S101.

[0048] Specifically, this step involves performing the inverse transformation from ENU coordinates to geographic coordinates through analytical calculation, as follows: Coordinate Transformation (ENU → Geographic Coordinates): Unlike the iterative inverse transformation required in the traditional WGS84 coordinate system, the inverse transformation in this method is a purely analytical calculation, requiring no iteration. It directly converts the compensated second coordinate information (E', N', U') into the corresponding geographic coordinate information (φ', λ', h') through linear inverse operations. The transformation formula is as follows:

[0049] Where φ' is the latitude of the target trajectory point in the converted geographic coordinate information, λ' is the longitude in the converted geographic coordinate information, and h' is the elevation in the converted geographic coordinate information, with units of degrees, degrees, and meters, respectively.

[0050] However, attention must be paid to boundary conditions. When the longitude migration exceeds 180 degrees, 360 degrees must be subtracted, and the latitude must be forcibly constrained to within ±90 degrees. The converted coordinates (i.e., the geographic coordinates corresponding to the compensated second coordinate information) are set as follows: This corrects out-of-range coordinates, ensuring the physical validity of the geographic coordinates. Specifically, after the step of performing coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information, the method further includes: Boundary processing is performed on the geographic coordinate information corresponding to the compensated second coordinate information to obtain processed geographic coordinate information; wherein, the boundary processing is to control the geographic coordinate information corresponding to the compensated second coordinate information within a preset reasonable coordinate range.

[0051] Understandably, the method for boundary processing of geographic coordinate information is as follows.

[0052] Because large-scale migration during coordinate transformation may cause λ' or φ' to exceed the physical range of geographic coordinates (effective longitude range: -180°~180°, effective latitude range: -90°~90°), boundary processing is required to control the geographic coordinates within a preset reasonable coordinate range. The specific processing rules are as follows: Longitude boundary processing: If the converted longitude λ' > 180°, subtract 360° from λ' (e.g., if λ' = 190°, correct to 190° - 360° = -170°); if λ' < -180°, add 360° to λ' to ensure that λ' is within the range of -180° to 180°.

[0053] Latitude boundary handling: If the converted latitude φ' > 90°, then φ' will be forcibly constrained to 90° (North Pole); if φ' < -90°, then it will be forcibly constrained to -90° (South Pole) to avoid latitude values ​​that do not exist physically.

[0054] After boundary processing, the processed geographic coordinate information (φ'_adj, λ'_adj, h'_adj) is obtained, laying the foundation for subsequent terrain adaptation and correction.

[0055] Accordingly, the step of correcting the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point includes: Based on the ground clearance of the target trajectory point, the processed geographic coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

[0056] S105: Based on the ground clearance of the target trajectory point, the geographic coordinate information corresponding to the compensated second coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

[0057] In this embodiment, the geographic coordinate information corresponding to the compensated second coordinate information can be corrected according to the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point. A Digital Elevation Model (DEM) refers to a grid data model that describes the terrain elevation information of the area corresponding to the target trajectory point. Its data is stored in raster form, and each raster point contains a corresponding terrain elevation value, used to calculate the terrain elevation below the target trajectory point.

[0058] As an example, a bilinear interpolation algorithm can be used to calculate the terrain elevation of the digital elevation model corresponding to the target trajectory point. The digital elevation model corresponds to the region corresponding to the target trajectory point. Terrain elevation (h) terrain The elevation (h) refers to the ground elevation of the trajectory point in the DEM, calculated from the DEM raster data using a bilinear interpolation algorithm, and is expressed in meters. Specifically, the method for calculating the terrain elevation corresponding to the target trajectory point is as follows: First, preload the DEM data of the area corresponding to the target trajectory point (no need to load the global DEM, reducing memory usage). Then, use a bilinear interpolation algorithm to calculate the terrain elevation h of the target trajectory point in the DEM. terrain Bilinear interpolation balances computational efficiency and accuracy. Specifically, the bilinear interpolation algorithm formula is as follows:

[0059] Among them, h terrain Here, represents the terrain elevation of the digital elevation model corresponding to the target trajectory point; u and v are the normalized offsets of the target trajectory point in the DEM grid (values ​​ranging from 0 to 1, calculated from the relative position of the target trajectory point's latitude and longitude to the DEM grid boundary); h 11 h 12 h 21 h 22 These are the elevations of the four DEM grid points adjacent to the target trajectory point (read from the preloaded DEM data), in meters.

[0060] Then, the ground clearance of the target trajectory point can be determined based on the terrain elevation. Ground clearance (AGL) refers to the difference between the elevation of the trajectory point and the corresponding terrain elevation, i.e., AGL = h' - h terrain Where h' is the elevation in the geographic coordinates obtained after compensation and transformation of the second coordinate information, in meters, used to determine whether the trajectory point has the risk of "burrowing" or "suspending". The ground clearance of the target trajectory point is calculated by comparing the elevation h'_adj in the processed geographic coordinate information or the elevation in the geographic coordinates obtained after compensation and transformation of the second coordinate information with the terrain elevation h. terrain The formula for calculating the ground clearance AGL is as follows: AGL = h' - h terrain In the formula, AGL is in meters. If AGL is positive, it means that the target trajectory point is above the terrain; if it is negative, it means that the target trajectory point is "underground" and needs to be forcibly corrected.

[0061] Next, based on the ground clearance of the target trajectory point and the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information can be corrected to obtain the target coordinate information of the target trajectory point. Minimum ground clearance (h) min_AGL This refers to the minimum height above the ground that the trajectory point must maintain. For example, a value of 100m is used to ensure that the target does not touch the ground during its movement.

[0062] As an example, if the ground clearance of the target trajectory point is less than the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information is corrected based on the preset minimum ground clearance and the preset safety margin to obtain the target coordinate information of the target trajectory point. That is, only the elevation value in the target coordinate information of the target trajectory point needs to be corrected; other parameters do not need to be corrected. The safety margin (h...) margin This refers to the additional elevation margin set to avoid collisions caused by abrupt changes in terrain (such as steep slopes or protruding obstacles). For example, it can be set to 50m to further improve the safety of target movement. When the ground clearance of the target trajectory point is less than the preset minimum ground clearance, it indicates that the ground clearance of the target trajectory point is insufficient, and there is a risk of collision. The elevation needs to be corrected to "terrain elevation + minimum ground clearance + safety margin", as shown in the following formula: h' final = h terrain + h min_AGL + h margin , where h' final h represents the elevation in the target coordinate information of the target trajectory point. terrain h represents the terrain elevation. min_AGL h is the minimum height above the ground. margin For safety margin.

[0063] If the ground clearance of the target trajectory point is equal to or greater than the preset minimum ground clearance, the ground clearance of the target trajectory point is used as the target coordinate information of the target trajectory point. When the ground clearance of the target trajectory point is equal to or greater than the preset minimum ground clearance, it means that the ground clearance of the target trajectory point meets the safety requirements, and there is no need to correct the elevation. The elevation h' of the geographic coordinate information corresponding to the compensated second coordinate information is directly used, that is, h'_final = h'_. Finally, the target coordinate information of the target trajectory point is the geographic coordinate information (φ', λ', h') corresponding to the compensated second coordinate information. Of course, the processed geographic coordinate information (φ'_adj, λ'_adj, h'_adj) can also be directly used. This target coordinate information takes into account accuracy, real-time performance, and safety, and can be directly used for subsequent analysis of the trajectory to be processed (such as path planning and collision detection).

[0064] In other words, the terrain height is different before and after displacement. Taking a flying target as an example, there may be situations where the safe altitude above the ground (safe flight altitude) and the collision avoidance safety altitude (collision that may occur due to sudden changes in terrain) are insufficient. Therefore, it is necessary to determine the target's motion altitude after displacement to the target area. If it is lower than a certain threshold, in order to ensure safety, the target trajectory must be corrected in altitude to ensure that the target always maintains sufficient altitude above the ground and collision avoidance safety margin during flight.

[0065] The elevation can be corrected based on the height above the ground to obtain the target coordinate information: based on AGL and the preset minimum height above the ground h. min_AGL The elevation of the processed geographic coordinate information is corrected based on a relationship such as (e.g., 100m). The specific correction rules are as follows: When AGL <h min_AGL (e.g., 100m): This indicates that the target trajectory point's ground clearance is insufficient, posing a collision risk. The elevation needs to be corrected to "terrain elevation + minimum ground clearance + safety margin", as shown in the formula below: h' final = h terrain +h min_AGL + h margin , where h' final h represents the elevation in the target coordinate information of the target trajectory point. terrain h represents the terrain elevation. min_AGL h is the minimum height above the ground. margin For safety margin.

[0066] When AGL ≥ h_min_AGL (e.g., 100m): This indicates that the ground clearance of the target trajectory point meets the safety requirements, and no elevation correction is needed. The processed elevation h'_adj is directly used, i.e., h'_final = h'_adj. Finally, the target coordinate information of the target trajectory point is (φ'_adj, λ'_adj, h'_final). Alternatively, the elevation h' corresponding to the geographic coordinate information after compensation of the second coordinate information can be directly used, i.e., h'_final = h'_. Ultimately, the target coordinate information of the target trajectory point is the geographic coordinate information (φ', λ', h') corresponding to the compensated second coordinate information. This coordinate information balances accuracy, real-time performance, and safety, and can be directly used for subsequent analysis of the trajectory to be processed (e.g., path planning, collision detection).

[0067] In addition, to improve batch processing efficiency, the S105 can combine multi-threading technology to process thousands of target trajectory points in parallel, compressing the time for terrain adaptation and correction at the thousand-point level to the millisecond level, further meeting the processing needs of high-frequency dynamic trajectories.

[0068] As can be seen from the above technical solution, this application has the following beneficial effects compared with the prior art: This coordinate determination method significantly improves the efficiency and accuracy of determining the coordinates of target trajectory points in the trajectory to be processed through the synergistic effect of the following steps: First, the origin of the ENU coordinate system is set as the first trajectory point of the trajectory to be processed, ensuring strict alignment between the trajectory and the ENU coordinate system. This avoids the complex ellipsoidal coordinate transformation under the traditional WGS84 coordinate system, enabling rapid acquisition of the first coordinate information of the target trajectory point in the ENU coordinate system and simplifying the initial coordinate acquisition process. Second, the first coordinate information is directly subjected to an affine transformation to obtain the second coordinate information, without the need to first transform the coordinates to the ECEF coordinate system. Compared with the traditional global affine transformation, this significantly reduces intermediate calculation steps and improves the coordinate transformation speed. Third, based on the second coordinate information and the ENU coordinate system... The displacement distance of the coordinate system origin is used to perform curvature compensation on the second coordinate information, which can be specifically adapted to different displacement distance scenarios (e.g., no compensation is needed when the displacement distance is small, first-order approximation compensation is used for medium distances, and second-order approximation compensation is used for large distances), avoiding the additional iterative burden of traditional curvature compensation and reducing the amount of computation while ensuring coordinate accuracy. Then, the compensated second coordinate information is converted into geographic coordinate information. This conversion process is a simple analytical calculation without iteration, which further shortens the coordinate conversion time compared to the inverse conversion of traditional ECEF and WGS84. Finally, the geographic coordinate information is corrected according to the ground clearance of the target trajectory point, which can effectively avoid unreasonable situations such as "drilling" or "suspending", ensuring that the target coordinate information of the target trajectory point is reasonable. In summary, the whole method improves the computational efficiency and real-time performance by simplifying the calculation and reducing iterations when determining the target coordinate information of the target trajectory point, and ensures the accuracy and reasonableness of the coordinates through targeted curvature compensation and ground clearance correction. It solves the problem that traditional methods are difficult to balance efficiency and accuracy, and can meet the coordinate determination requirements of high-frequency dynamic target trajectories.

[0069] It is understandable that this method can achieve the following technical effects in practical applications: Significantly improved computational efficiency: Compared with the iterative transformation of the traditional WGS84 coordinate system, the coordinate transformation (forward / inverse transformation) of this method is a linear operation, which improves the single-point processing efficiency by nearly 30 times and the migration delay can be controlled within 5ms, meeting the real-time processing requirements of high-frequency dynamic targets.

[0070] Controllable accuracy over a wide range of displacements: Through graded curvature compensation, the planar error is less than 15 meters and the height error is less than 5 meters within a displacement range of 200km, with accuracy close to that of the traditional WGS84 scheme, while avoiding the additional iterative compensation burden of the traditional scheme.

[0071] Reduced hardware resource consumption: CPU floating-point operations are reduced by about 70%, there is no need to cache global ECEF coordinates, and peak memory usage is significantly reduced, making it suitable for embedded devices or edge computing devices.

[0072] High terrain adaptation efficiency: By preloading local DEM data and correcting the ground clearance, the "drilling" or "suspending" problem is effectively avoided. At the same time, multi-threaded parallel processing further improves the adaptation efficiency of batch trajectories.

[0073] like Figure 3 The image shows a specific embodiment of a coordinate determination device provided in this application. The device described in this embodiment is a physical device used to perform the method described in the above embodiments. Its technical solution is essentially the same as that of the above embodiments, and the corresponding descriptions in the above embodiments also apply to this embodiment. The large inertia on-orbit device includes an actuator, and the device includes: The first unit 301 is used to obtain the ENU coordinate system corresponding to the trajectory to be processed; wherein, the origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed; The second unit 302 is used to obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and to perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. The third unit 303 is used to perform curvature compensation on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information; wherein, the displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system; The fourth unit 304 is used to perform coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information; The fifth unit 305 is used to correct the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point, so as to obtain the target coordinate information of the target trajectory point.

[0074] Optionally, obtaining the ENU coordinate system corresponding to the trajectory to be processed includes: Obtain the geographic coordinates of the first trajectory point of the trajectory to be processed; The geographic coordinate information of the first trajectory point is converted into the first coordinate information of the first trajectory point in the ENU coordinate system; The first coordinate information of the first trajectory point in the ENU coordinate system is used as the origin of the ENU coordinate system, and the ENU coordinate system corresponding to the trajectory to be processed is established.

[0075] Optionally, the step of performing an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system includes: The first coordinate information is rotated and translated to obtain the second coordinate information of the target trajectory point in the ENU coordinate system.

[0076] Optionally, the step of performing curvature compensation on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information includes: The distance between the second coordinate information and the origin of the ENU coordinate system is taken as the displacement distance corresponding to the second coordinate information; If the displacement distance corresponding to the second coordinate information is less than or equal to the first preset threshold, the second coordinate information will be used as the compensated second coordinate information; If the displacement distance corresponding to the second coordinate information is greater than the first preset threshold and less than or equal to the second preset threshold, the second coordinate is curvature compensated using a first-order approximate compensation method to obtain the compensated second coordinate information. If the displacement distance corresponding to the second coordinate information is greater than the second preset threshold, the second coordinate is subjected to curvature compensation using a second-order approximation compensation method to obtain the compensated second coordinate information.

[0077] Optionally, the step of correcting the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point includes: The terrain elevation of the digital elevation model corresponding to the target trajectory point is calculated using a bilinear interpolation algorithm; the digital elevation model corresponds to the region corresponding to the target trajectory point. Based on the terrain elevation, determine the ground clearance of the target trajectory point; Based on the ground clearance of the target trajectory point and the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

[0078] Optionally, the step of correcting the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point and the preset minimum ground clearance to obtain the target coordinate information of the target trajectory point includes: If the ground clearance of the target trajectory point is less than the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information is corrected according to the preset minimum ground clearance and the preset safety margin to obtain the target coordinate information of the target trajectory point. If the ground clearance of the target trajectory point is equal to or greater than the preset minimum ground clearance, the ground clearance of the target trajectory point is used as the target coordinate information of the target trajectory point.

[0079] Optionally, the device further includes a sixth unit, configured to: after the step of performing coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information, perform boundary processing on the geographic coordinate information corresponding to the compensated second coordinate information to obtain processed geographic coordinate information; wherein, the boundary processing is to control the geographic coordinate information corresponding to the compensated second coordinate information within a preset reasonable coordinate range. Accordingly, the step of correcting the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point includes: Based on the ground clearance of the target trajectory point, the processed geographic coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

[0080] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. At the hardware level, the electronic device includes a processor, and optionally also includes an internal bus, a network interface, and a memory. The memory may include RAM, such as high-speed random-access memory (RAM), or non-volatile memory, such as at least one disk storage device. Of course, the electronic device may also include other hardware required for other services.

[0081] The processor, network interface, and memory can be interconnected via an internal bus, which can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. This bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0082] Memory is used to store instructions for execution. Specifically, instructions for execution are computer programs that can be executed. Memory can include main memory and non-volatile memory, and it provides the processor with execution instructions and data.

[0083] In one possible implementation, the processor reads the corresponding execution instructions from non-volatile memory into memory and then executes them. Alternatively, it may obtain the corresponding execution instructions from other devices to form a coordinate determination device at the logical level. The processor executes the execution instructions stored in memory to implement the coordinate determination method provided in any embodiment of this application through the executed instructions.

[0084] The above is as stated in this application. Figure 1 The method executed by the coordinate determination device provided in the illustrated embodiment can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor.

[0085] The steps of the method disclosed in the embodiments of this application can be directly manifested as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0086] This application also proposes a readable medium that stores execution instructions. When the stored execution instructions are executed by the processor of an electronic device, the electronic device can execute the coordinate determination method provided in any embodiment of this application and specifically perform the above-mentioned evaluation method.

[0087] The electronic devices described in the foregoing embodiments may be computers.

[0088] Those skilled in the art will understand that the embodiments of this application can be provided as methods or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or a combination of software and hardware.

[0089] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0090] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining coordinates, characterized in that, The method includes: Obtain the ENU coordinate system corresponding to the trajectory to be processed; wherein, the origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed; Obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. Based on the displacement distance corresponding to the second coordinate information, curvature compensation is performed on the second coordinate information to obtain the compensated second coordinate information; wherein, the displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system; The compensated second coordinate information is transformed to obtain the geographic coordinate information corresponding to the compensated second coordinate information. Based on the ground clearance of the target trajectory point, the geographic coordinate information corresponding to the compensated second coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

2. The method according to claim 1, characterized in that, The step of obtaining the ENU coordinate system corresponding to the trajectory to be processed includes: Obtain the geographic coordinates of the first trajectory point of the trajectory to be processed; The geographic coordinate information of the first trajectory point is converted into the first coordinate information of the first trajectory point in the ENU coordinate system; The first coordinate information of the first trajectory point in the ENU coordinate system is used as the origin of the ENU coordinate system, and the ENU coordinate system corresponding to the trajectory to be processed is established.

3. The method according to claim 1, characterized in that, The step of performing an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system includes: The first coordinate information is rotated and translated to obtain the second coordinate information of the target trajectory point in the ENU coordinate system.

4. The method according to claim 1, characterized in that, The step of performing curvature compensation on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information includes: The distance between the second coordinate information and the origin of the ENU coordinate system is taken as the displacement distance corresponding to the second coordinate information; If the displacement distance corresponding to the second coordinate information is less than or equal to the first preset threshold, the second coordinate information will be used as the compensated second coordinate information; If the displacement distance corresponding to the second coordinate information is greater than the first preset threshold and less than or equal to the second preset threshold, the second coordinate is curvature compensated using a first-order approximate compensation method to obtain the compensated second coordinate information. If the displacement distance corresponding to the second coordinate information is greater than the second preset threshold, the second coordinate is subjected to curvature compensation using a second-order approximation compensation method to obtain the compensated second coordinate information.

5. The method according to claim 1, characterized in that, The step of correcting the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point includes: The terrain elevation of the digital elevation model corresponding to the target trajectory point is calculated using a bilinear interpolation algorithm; the digital elevation model corresponds to the region corresponding to the target trajectory point. Based on the terrain elevation, determine the ground clearance of the target trajectory point; Based on the ground clearance of the target trajectory point and the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

6. The method according to claim 5, characterized in that, The step of correcting the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point and the preset minimum ground clearance to obtain the target coordinate information of the target trajectory point includes: If the ground clearance of the target trajectory point is less than the preset minimum ground clearance, the elevation value of the geographic coordinate information corresponding to the compensated second coordinate information is corrected according to the preset minimum ground clearance and the preset safety margin to obtain the target coordinate information of the target trajectory point. If the ground clearance of the target trajectory point is equal to or greater than the preset minimum ground clearance, the ground clearance of the target trajectory point is used as the target coordinate information of the target trajectory point.

7. The method according to claim 1, characterized in that, After the step of performing coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information, the method further includes: The geographic coordinate information corresponding to the compensated second coordinate information is subjected to boundary processing to obtain the processed geographic coordinate information; wherein, the boundary processing is to control the geographic coordinate information corresponding to the compensated second coordinate information within a preset reasonable coordinate range. Accordingly, the step of correcting the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point to obtain the target coordinate information of the target trajectory point includes: Based on the ground clearance of the target trajectory point, the processed geographic coordinate information is corrected to obtain the target coordinate information of the target trajectory point.

8. A coordinate determining device, characterized in that, The device includes: The first unit is used to obtain the ENU coordinate system corresponding to the trajectory to be processed; wherein the origin of the ENU coordinate system is the first trajectory point of the trajectory to be processed; The second unit is used to obtain the first coordinate information of the target trajectory point in the ENU coordinate system in the trajectory to be processed, and to perform an affine transformation on the first coordinate information to obtain the second coordinate information of the target trajectory point in the ENU coordinate system. The third unit is used to perform curvature compensation on the second coordinate information based on the displacement distance corresponding to the second coordinate information to obtain the compensated second coordinate information; wherein, the displacement distance is the distance between the second coordinate information and the origin of the ENU coordinate system; The fourth unit is used to perform coordinate transformation on the compensated second coordinate information to obtain the geographic coordinate information corresponding to the compensated second coordinate information; The fifth unit is used to correct the geographic coordinate information corresponding to the compensated second coordinate information based on the ground clearance of the target trajectory point, so as to obtain the target coordinate information of the target trajectory point.

9. A readable medium, characterized in that, The method includes execution instructions, which, when executed by the processor of the electronic device, cause the electronic device to perform the method as described in any one of claims 1-7.

10. An electronic device, characterized in that, The method includes a processor and a memory storing execution instructions. When the processor executes the execution instructions stored in the memory, the processor performs the method as described in any one of claims 1-7.

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