A method for converting geodetic height to Wusong elevation within the CGCS2000 framework

Abstract

This invention relates to a method for converting geodetic height to Wusong elevation within the CGCS2000 framework. The steps include: calculating the average difference between the spatial rectangular coordinates of multiple CORS stations in the WGS84 and CGCS2000 coordinate systems; subtracting the average difference from the spatial rectangular coordinates in the CGCS2000 coordinate system to obtain the spatial rectangular coordinates of the second station; converting the spatial rectangular coordinates of the second station to a geodetic coordinate system (B1, L1, H1); calculating the average difference H2 between the geodetic height H1 and the WGS84 geodetic height of each CORS station; converting the CGCS2000 coordinates to be converted to Wusong elevation H3 within the WGS84 framework; and subtracting the average difference H2 from the Wusong elevation H3 to obtain the Wusong elevation of the point to be converted. Compared with existing technologies, this invention can achieve geodetic height conversion to Wusong elevation without a refined geoid model within the CGCS2000 framework.

Description

Technical Field

[0001] This invention relates to the fields of geodesy and surveying engineering, and in particular to a method for converting geodetic height into Wusong elevation under different reference ellipsoid frames. Background Technology

[0002] In fields such as geodesy and surveying engineering, GNSS is usually used to carry out surveying activities, which can easily obtain geodetic height results under different reference ellipsoids. However, for practical work involving planning, construction, archiving, etc., Wusong height results are required.

[0003] In areas with flat terrain and minimal elevation fluctuations, if the surveying and mapping authorities have already published and released the corresponding geoid refinement model for a given reference frame, we can directly convert the geodetic height to the Wusong elevation. However, converting geodetic height to Wusong elevation under a reference ellipsoid without a geoid refinement model is a problem that needs to be solved in some engineering projects. This invention aims to solve the problem of mutual conversion between geodetic height and Wusong elevation under the CGCS2000 reference ellipsoid without a geoid refinement model, providing a solution for the implementation of related projects. Summary of the Invention

[0004] This invention mainly solves the problem of converting geodetic height and Wusong elevation within a small area using the CGCS2000 framework, and provides a method for converting geodetic height and Wusong elevation with high accuracy.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] As a first aspect of the present invention, a method for converting geodetic height to Wusong elevation under the CGCS2000 framework is provided, the steps of which include:

[0007] Step 1: Calculate the mean difference between the spatial rectangular coordinates of multiple CORS stations in the WGS84 and CGCS2000 coordinate systems;

[0008] Step 2: Subtract the mean difference value of the spatial rectangular coordinates from the spatial rectangular coordinates of the CORS station in the CGCS2000 coordinate system to obtain the spatial rectangular coordinates (X, Y, Z1) of the second station.

[0009] Step 3: Convert the spatial rectangular coordinate system (X1, Y1, Z1) of the second station to the geodetic coordinate system (B1, L1, H1), and calculate the average difference H2 between the geodetic height H1 of the converted geodetic coordinate system and the WGS84 geodetic height of each CORS station.

[0010] Step 4: Convert the CGCS2000 coordinates of the points to be converted into the Wusong elevation result H3 within the WGS84 framework;

[0011] Step 5: Subtract the average difference value H2 of the geodetic height from the converted Wusong elevation result H3 to obtain the Wusong elevation of the point to be converted.

[0012] Furthermore, the WGS84 uses ITRF2008 as a reference frame.

[0013] Furthermore, the spatial rectangular coordinates of the WGS84 and CGCS2000 coordinate systems are obtained by baseline calculation and network adjustment of static control measurement data of multiple GNSS points and observation data of multiple CORS reference stations.

[0014] Furthermore, the baseline is calculated using double-difference observations.

[0015] Furthermore, the factors considered during the baseline calculation include:

[0016] Model correction for satellite clock bias;

[0017] Model correction for receiver clock bias;

[0018] The effect of ionospheric refraction;

[0019] The effect of tropospheric refraction;

[0020] Phase center correction for satellite and receiver antennas;

[0021] Tidal correction for station location;

[0022] Cutoff height angle and epoch interval;

[0023] Satellite orbital error;

[0024] The accuracy of satellite orbits.

[0025] Furthermore, the model for satellite clock bias is corrected using clock bias parameters from broadcast ephemeris;

[0026] The receiver clock error model calculates clock error correction based on pseudorange observations;

[0027] The effects of ionospheric refraction were eliminated using LC observations;

[0028] The tropospheric refraction was corrected using the Saastamoinen model based on the standard atmospheric model, and the refraction deviation parameter was estimated using a piecewise linear method.

[0029] The satellite orbit was determined using IGS post-hoc precise ephemeris.

[0030] Furthermore, after the baseline is solved, the three-dimensional baseline vectors of the independent baselines and the corresponding variance-covariance matrix are used as observation information. After passing the gross error detection, the corresponding benchmark is selected for three-dimensional constrained adjustment.

[0031] Furthermore, the CGCS2000 coordinate values ​​of the points to be converted are transformed into the Wusong elevation result H3 through the existing geoid refinement model under the WGS84 framework.

[0032] As a second aspect of the present invention, an electronic device is provided, comprising:

[0033] One or more processors;

[0034] Memory, used to store one or more programs;

[0035] When the one or more programs are executed by the one or more processors, the one or more processors implement the geodetic height to Wusong elevation conversion method under the CGCS2000 framework as described in any of the preceding claims.

[0036] As a third aspect of the present invention, a computer-readable storage medium is provided having computer instructions stored thereon.

[0037] When executed by the processor, this instruction implements the steps of the geodetic height to Wusong elevation conversion method under the CGCS2000 framework as described in any of the preceding items.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1) Without the CGCS2000 framework or its reference framework geoid refinement model, this invention can achieve mutual conversion between geodetic height and Wusong elevation through calculation.

[0040] 2) The geodetic elevation and Wusong elevation conversion method provided by this invention can be used to calculate Wusong elevation results with an accuracy of about 2cm in areas where Wusong elevation is used for related work. Attached Figure Description

[0041] Figure 1 A schematic flowchart illustrating the geodetic height to Wusong elevation conversion method provided by the present invention;

[0042] Figure 2 This is a schematic diagram of the measurement points within the area in Embodiment 2 of the present invention;

[0043] Figure 3 A schematic diagram of an electronic device shown in an embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] Example 1

[0046] This invention provides a method for converting CGCS2000 coordinate system geodetic height to Wusong elevation. By calculating the difference between two reference ellipsoids, the CGCS2000 geodetic height measured by the CORS system can be converted to Wusong elevation under certain accuracy requirements. Geodetic height represents the distance from a point on the ground to the reference ellipsoid along the normal to the ellipsoid passing through that point.

[0047] like Figure 1 As shown, the technical solution adopted in this invention, a method for converting geodetic height and Wusong elevation under the CGCS2000 framework suitable for small plain areas, includes the following steps:

[0048] Step 1: Calculate the mean difference between the spatial rectangular coordinates of the WGS84 (ITRF2008 reference frame) and CGCS2000 coordinate systems of the 10 CORS system sites.

[0049] Step 2: Subtract the mean difference value from the spatial rectangular coordinates (X, Y, Z) of the 10 CORS sites in the CGCS2000 coordinate system to obtain the new (X1, Y1, Z1).

[0050] Step 3: Convert the values ​​of the new spatial rectangular coordinate system (X1, Y1, Z1) to geodetic coordinate system results (B1, L1, H1), and calculate the average difference between the geodetic height H1 of the 10 points and the geodetic height of WGS84 (ITRF2008 reference frame), which is defined as H2.

[0051] Step 4: The user obtains the Wusong elevation result H3 by using the existing geoid refinement module based on the WGS84 framework to obtain the CGCS2000 coordinate values ​​of the point to be measured.

[0052] Step 5: Subtract the mean difference value of geodetic height H2 from the Wusong elevation result H3 to obtain the Wusong elevation of the relevant points.

[0053] Example 2

[0054] Taking Shanghai as an example, based on known information, the geoid refinement module of the Shanghai Satellite Navigation and Positioning Reference Service System is currently developed based on WGS84 and can convert WGS84 geodetic height to Wusong height. Using the geodetic height and Wusong height conversion method under the CGCS2000 framework as described in Example 1, the geodetic height of the point to be measured under the CGCS2000 framework is converted to Wusong height.

[0055] like Figure 2 As shown, static control measurements were conducted on selected GNSS points in Shanghai, with a total of 28 points measured, of which 20 points met the observation quality requirements.

[0056] The baseline data used were observation data from 10 SHCORS system stations, covering a period of 14 days from March 9th to March 23rd, 2021, with a sampling interval of 30 seconds. To calculate the CGCS2000 and WGS84 coordinates of the 20 control points, baseline calculation and network adjustment were performed together with the observation data from the 10 SHCORS stations.

[0057] Baseline calculation was performed using GAMIT software. The baseline calculation employed double-difference observations, and the software primarily considered the following factors during the calculation:

[0058] Model correction for satellite clock bias (using clock bias parameters from broadcast ephemeris);

[0059] Model correction for receiver clock bias (using clock bias calculated from pseudorange observations);

[0060] The effects of ionospheric refraction are eliminated using LC observations;

[0061] Tropospheric refraction was corrected using the Saastamoinen model based on the standard atmospheric model, and the refraction deviation parameter was estimated using a piecewise linear method.

[0062] The phase center correction of the satellite and receiver antennas is performed, and the phase center deviation of receiver antennas L1 and L2 is set using the values ​​of GAMIT software.

[0063] Tidal correction for station location;

[0064] The cutoff elevation angle is 15 degrees, and the epoch interval is 15 seconds;

[0065] Consider satellite orbital errors, i.e., relax the IGS orbit;

[0066] The accuracy of satellite orbits is a crucial factor affecting the accuracy of GNSS baseline calculations; therefore, post-hoc precise ephemeris analysis using IGS should be employed.

[0067] After all baseline quality checks meet the standards, the three-dimensional baseline vectors and corresponding variance-covariance matrices of the independent baselines are used as observation information. Three-dimensional unconstrained adjustment is performed first, and after the gross error detection is qualified, the corresponding benchmark is selected for three-dimensional constrained adjustment.

[0068] The main purpose of three-dimensional unconstrained adjustment is to check whether the GNSS baseline vector contains gross errors or obvious systematic errors, to examine the random model error of the baseline vector, and to examine the internal accuracy of the GNSS network.

[0069] The elevation of Wusong was calculated using the CGCS2000 and WGS84 coordinate system results of the adjusted control points. After the difference values ​​were averaged according to the method proposed in this paper, the results were compared with those using the geoid refinement software based on the WGS84 framework available from the Shanghai Institute of Surveying and Mapping (https: / / cors.shanghai-map.net:10050 / ).

[0070] As shown in Table 1, after processing the measurement results using the geoid refinement module based on the WGS84 framework, the maximum difference between the result obtained by subtracting the constant calculated by the method proposed in this paper and the original Wusong elevation does not exceed 2 cm.

[0071] Table 1 Comparison of Wusong Elevation Results

[0072]

[0073]

[0074] In summary, the method proposed in this paper can achieve mutual conversion between geodetic elevation and Wusong elevation in certain scenarios, and can realize high-precision mutual conversion between geodetic elevation and Wusong elevation even without a geoid refinement model under the CGCS2000 reference frame.

[0075] Example 3

[0076] As a second aspect of the present invention, this application also provides an electronic device, comprising: one or more processors 11; and a memory 12 for storing one or more programs; when the one or more programs are executed by the one or more processors 11, the one or more processors 11 implement the geodetic height to Wusong elevation conversion method under the CGCS2000 framework described above. Figure 3 The diagram shown illustrates a hardware structure of any data processing device within the CGCS2000 framework for the geodetic height to Wusong elevation conversion method provided in this embodiment of the invention, except for... Figure 3In addition to the processor 11, memory 12 and interface 13 shown, any data processing device in the embodiment may also include other hardware depending on the actual function of the data processing device, which will not be described in detail here.

[0077] Example 4

[0078] As a third aspect of the present invention, this application also provides a computer-readable storage medium storing computer instructions thereon, which, when executed by a processor, implement the geodetic height to Wusong elevation conversion method under the CGCS2000 framework described above. The computer-readable storage medium can be an internal storage unit of any data processing device as described in any of the foregoing embodiments, such as a hard disk or memory. The computer-readable storage medium can also be an external storage device, such as a plug-in hard disk, smart media card (SMC), SD card, flash card, etc., equipped on the device. Furthermore, the computer-readable storage medium can include both internal storage units of any data processing device and external storage devices. The computer-readable storage medium is used to store the computer program and other programs and data required by the data processing device, and can also be used to temporarily store data that has been output or will be output.

[0079] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for converting geodetic height to Wusong elevation under the CGCS2000 framework, characterized in that, The steps of the conversion method include: Step 1: Calculate the mean difference between the spatial rectangular coordinates of multiple CORS stations in the WGS84 and CGCS2000 coordinate systems; Step 2: Subtract the mean difference value of the spatial rectangular coordinates from the spatial rectangular coordinates of the CORS station in the CGCS2000 coordinate system to obtain the spatial rectangular coordinates (X, Y, Z1) of the second station. Step 3: Convert the spatial rectangular coordinate system (X1, Y1, Z1) of the second station to the geodetic coordinate system (B1, L1, H1), and calculate the average difference H2 between the geodetic height H1 of the converted geodetic coordinate system and the WGS84 geodetic height of each CORS station. Step 4: Convert the CGCS2000 coordinates of the points to be converted into the Wusong elevation result H3 within the WGS84 framework; Step 5: Subtract the average difference value H2 of the geodetic height from the converted Wusong elevation result H3 to obtain the Wusong elevation of the point to be converted.

2. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 1, characterized in that, The WGS84 uses ITRF2008 as the reference frame.

3. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 1, characterized in that, The spatial rectangular coordinates of the WGS84 and CGCS2000 coordinate systems are obtained by baseline calculation and network adjustment of static control measurement data of multiple GNSS points and observation data of multiple CORS reference stations.

4. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 3, characterized in that, The baseline was calculated using double-difference observations.

5. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 3, characterized in that, The factors considered in the baseline calculation include: Model correction for satellite clock bias; Model correction for receiver clock bias; Influence of ionospheric refraction; The effect of tropospheric refraction; Phase center correction for satellite and receiver antennas; Tidal correction for station location; Cutoff height angle and epoch interval; Satellite orbital error; The accuracy of satellite orbits.

6. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 5, characterized in that, The satellite clock bias model is corrected using clock bias parameters from broadcast ephemeris. The receiver clock error model calculates clock error correction based on pseudorange observations; The effects of ionospheric refraction were eliminated using LC observations; The tropospheric refraction was corrected using the Saastamoinen model based on the standard atmospheric model, and the refraction deviation parameter was estimated using a piecewise linear method. The satellite orbit was determined using IGS post-hoc precise ephemeris.

7. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 3, characterized in that, After the baseline is solved, the three-dimensional baseline vectors of the independent baselines and the corresponding variance-covariance matrix are used as observation information. After the gross error detection is qualified, the corresponding benchmark is selected for three-dimensional constrained adjustment.

8. The method for converting geodetic height to Wusong elevation under the CGCS2000 framework according to claim 1, characterized in that, The CGCS2000 coordinate values ​​of the points to be converted are transformed into the Wusong elevation result H3 using the existing geoid refinement model under the WGS84 framework.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the geodetic height to Wusong elevation conversion method under the CGCS2000 framework as described in any one of claims 1-7.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method for converting geodetic height to Wusong elevation under the CGCS2000 framework as described in any one of claims 1-7.

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