Evaluation method and system for control point distribution of GNSS reference station network

Abstract

The present application relates to the field of global satellite navigation technology, and discloses a method and system for evaluating the distribution of control points of a GNSS base station network. The method comprises: dividing a survey area into M plots of equal area; using a polygon algorithm to calculate the total number N of plots covered by at least one control point in the plots; during actual adjustment calculation, calculating the total number n of plots covered by at least one fixed control point in all plots; calculating the coverage rate c1 of the selected control points according to the total number N of plots covered by at least one control point in all plots, and calculating the coverage rate c2 of the fixed control points during actual adjustment according to the total number n of plots covered by at least one control point in all plots obtained by calculation during actual adjustment calculation, wherein c1=N / M, c2=n / M.

Description

Technical Field

[0001] The present application relates to the field of global satellite navigation technology, and in particular to a control point distribution uniformity assessment technology. Background Art

[0002] The base station network based on the Global Navigation Satellite (GNSS) system refers to a number of GNSS observation stations distributed around the world or in a region, including those that operate continuously and those that operate discontinuously. At present, the GNSS base station network can be roughly divided into four categories, namely, global network, national network, regional network, and engineering network, based on the distance, distribution range, and implementation functions between the base stations. The base station network and its system integrate GNSS, communication, meteorological data collection and other technologies. It is currently the main ground-based geographic information collection facility in the world and can be used in areas related to location and time. It is a supporting platform for GNSS to achieve high-precision navigation and location services, and is also an important infrastructure for scientific and engineering applications such as establishing a coordinate framework and monitoring crustal movement.

[0003] Among them, obtaining the precise coordinates of the base station is the basis for realizing the functions of the GNSS base station network, and high-precision GNSS data processing methods are the key to this basis.

[0004] Specifically, in the high-precision GNSS data processing method, the baseline components between the base stations are generally solved first, and then the known coordinate points (also called control points) are introduced for adjustment. Therefore, in this process, the number, quality and distribution of control points will affect the final solution result.

[0005] Generally speaking, control points should be evenly distributed throughout the survey area. If all control points are concentrated in a part or one side of the survey area, it is difficult to constrain the entire base station network. However, in current applications, there is no quantifiable indicator to measure the distribution characteristics of control points. The introduction of which control points mainly depends on the experience of data processing personnel, which makes it difficult to automate the entire process and it is impossible to evaluate the uniformity of the distribution of the introduced control points. Summary of the invention

[0006] The purpose of this application is to provide a GNSS base station network control point distribution evaluation method and system, which can more accurately and efficiently measure the uniformity of the introduced control points. Compared with traditional methods, it can not only quantify the uniformity of the control point distribution (or control point coverage), but also has a simple algorithm and is easy to program in a computer, thereby realizing automatic operation.

[0007] The present application discloses a method for evaluating the distribution of control points of a GNSS reference station network, comprising:

[0008] Divide the survey area into M plots of equal area, where M is an integer greater than 1;

[0009] Calculate the total number N of plots in the plot that are covered by at least one control point using a polygon algorithm;

[0010] During the actual adjustment calculation, the total number n of plots covered by at least one fixed control point among all plots is calculated;

[0011] The coverage rate c1 of the selected control points is calculated based on the total number N of plots covered by at least one control point among all plots, and the coverage rate c2 of the control points fixed during the actual adjustment is calculated based on the total number n of plots covered by at least one control point among all plots obtained during the actual adjustment, where c1=N / M and c2=n / M.

[0012] In a preferred example, it further comprises: adjusting the distribution uniformity of the control points according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

[0013] In a preferred example, the number of the plots is 1 / 5 to 1 / 6 of the total number of control points.

[0014] In a preferred example, the areas of the plots are equal.

[0015] In a preferred example, in the step of dividing the survey area into a plurality of plots of equal area, a graticule is used to divide the survey area into a plurality of plots of equal area; and / or a map projection algorithm is used to divide the survey area into a plurality of plots of equal area using projected coordinates; and / or a discrete global grid system algorithm is used to generate plot boundaries.

[0016] In a preferred example, in the step of dividing the survey area into a plurality of plots of equal area, the plots are triangles.

[0017] The present application also discloses a GNSS reference station network control point distribution evaluation system, comprising:

[0018] A segmentation module is used to segment the survey area into M plots of equal area, where M is an integer greater than 1;

[0019] A first calculation module, configured to calculate a total number N of plots covered by at least one control point in the plot using a polygon algorithm;

[0020] The second calculation module is used to calculate the total number n of plots covered by at least one fixed control point in all plots during the actual adjustment calculation;

[0021] A first coverage rate calculation module is used to calculate the coverage rate c1 of the selected control point according to the total number N of plots covered by at least one control point in all plots, where c1=N / M;

[0022] The second coverage rate calculation module is used to calculate the coverage rate c2 of the fixed control points during the actual adjustment according to the total number n of plots covered by at least one control point in all plots calculated during the actual adjustment calculation, where c2=n / M;

[0023] The distribution uniformity adjustment module is used to adjust the distribution uniformity of the control points according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

[0024] In a preferred example, the number of the plots is 1 / 5 to 1 / 6 of the total number of control points.

[0025] In a preferred example, the areas of the plots are equal.

[0026] In a preferred example, the plot of land is triangular.

[0027] In the implementation mode of the present application, the uniformity of the introduced control points can be measured more accurately and efficiently. Compared with the traditional method, it can not only realize the quantification of the uniformity of the control point distribution (or so-called control point coverage), but also the algorithm is simple and convenient to be programmed and implemented in a computer, thereby realizing automatic operation.

[0028] The specification of this application records a large number of technical features, which are distributed in various technical solutions. If all possible combinations of technical features (i.e., technical solutions) of this application are listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above invention content of this application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the drawings can be freely combined with each other to form various new technical solutions (these technical solutions are all deemed to have been recorded in this specification), unless such a combination of technical features is technically infeasible. For example, in one example, feature A+B+C is disclosed, and in another example, feature A+B+D+E is disclosed. Features C and D are equivalent technical means that play the same role. Technically, only one of them can be used, and it is impossible to use them at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be deemed to have been recorded because it is technically infeasible, while the solution of A+B+C+E should be deemed to have been recorded. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1is a flow chart of a method for evaluating the distribution of control points of a GNSS reference station network according to the first embodiment of the present application;

[0030] Figure 2 It is a structural schematic diagram of a GNSS reference station network control point distribution evaluation system according to the second embodiment of the present application. DETAILED DESCRIPTION

[0031] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0032] Description of some concepts:

[0033] GNSS: refers to Global navigation satellite system.

[0034] Multi-GNSS: refers to a multi-system global satellite positioning system.

[0035] CORS: refers to Continuously Operating Reference Stations.

[0036] RTK: refers to Real-time kinematic, real-time dynamic carrier phase differential positioning technology.

[0037] The following is a brief description of some of the innovative features of this application:

[0038] This specification proposes a method for evaluating the uniformity of control point distribution implemented by a computer. Compared with the traditional manual identification method, this method quantifies the uniformity characteristics of control point distribution and is more suitable for computer use.

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0040] The first embodiment of the present application relates to a method for evaluating the distribution of control points of a GNSS reference station network, the process of which is as follows: Figure 1 As shown, the method comprises the following steps:

[0041] Step 110: Divide the survey area into a plurality of plots of equal area, and the total number of plots is recorded as M.

[0042] The number of plots delineated in step 110 is very important. If the number of plots is too small, the area of ​​each plot will be relatively large, and the final coverage rate will be high. On the contrary, if the number of plots is too large, the area of ​​each plot will be relatively small, and the final coverage rate will be relatively low. Therefore, too many or too few plots will result in the final calculated coverage rate not correctly reflecting the actual situation.

[0043] Preferably, when the entire earth surface is used as the survey area, the number of divided plots may be 1 / 5 to 1 / 6 of the total number of control points.

[0044] Secondly, the divided plots should be equal or similar in area, otherwise the calculated coverage will be distorted.

[0045] Preferably, for a survey area with a small latitudinal span, a longitude and latitude grid can be used for division.

[0046] However, it should be pointed out that when the survey area is located in a high-latitude region or the latitude span of the survey area is large, due to the influence of the curvature of the earth's surface, the use of longitude and latitude grids to divide the plots will lead to large differences in the areas of plots at different latitudes.

[0047] In this case, the preferred methods that can be used are:

[0048] 1) Use an appropriate (small deformation) map projection algorithm to project the survey area onto a plane and use the projected coordinates to divide it. The advantage of this method is that it is easy to implement and easy to understand. Preferably, this method is used for survey areas with a small longitude and latitude span. Otherwise, the calculation of coverage will be biased due to excessive projection deformation. For example, a map projection algorithm is used in the survey area, and the projected coordinates are used to divide the survey area into multiple plots of equal area.

[0049] 2) Use the Discrete Global Grid System (DGGS) algorithm to generate plot boundaries. The advantage of this method is that it works well for survey areas of different latitudes and sizes, and the generated plots have consistent shapes and equal areas.

[0050] Finally, the shape of the plots used to divide the survey area also needs to be considered, which is related to step 120 and step 130. Specifically, these two steps require calculating whether the control point is within a certain plot. Currently mature and widely used algorithms are generally only applicable to convex polygons.

[0051] In this case, preferably, a convex polygon is used when dividing the measurement area, for example, a triangle, but not limited to, a rectangle, a hexagon, etc.

[0052] The advantage of doing this is that it ensures the simplicity and reliability of the polygon algorithm.

[0053] In addition, when longitude and latitude are used as point coordinates, special processing is required when the survey area crosses the prime meridian or the 180° meridian. This is reflected in: when longitude is stored from 0 to 360, when the polygon crosses the 0° meridian, there will be problems in calculating whether the point is inside the polygon; similarly, when longitude is stored from -180 to 180, when the polygon crosses the 180° meridian, there will be problems in calculating whether the point is inside the polygon.

[0054] In this case, the following solutions are preferred:

[0055] 1) Through reasonable division, each plot is not crossed by the 0° or 180° longitude.

[0056] 2) When the survey area crosses the 0° and 180° meridians at different times, the longitude storage method can be flexibly selected to avoid it. For example, when the survey area only crosses the 180° longitude, the longitude can be stored in the form of 0 to 360, 0-180 represents east longitude, and 180-360 represents west longitude. This avoids the problem when the plot crosses the 180° longitude.

[0057] 3) When it is unavoidable to cross a plot that straddles both the 0° and 180° meridians, the plot that straddles the 0° and 180° meridians can be cut into multiple sub-plots along the 0° or 180° meridian and calculated separately. For example, a polygon that straddles the 180° meridian can be split into two sub-polygons along the 180° meridian and calculated separately. However, when a point falls in any of the sub-polygons, it can be considered that the point is within the large polygon.

[0058] Let's take a more specific example to further illustrate:

[0059] Preferably, the earth's surface can be divided into a number of roughly uniform plots, for example, by dividing them into 32 spherical triangles using the following method.

[0060] The triangle numbers and vertex coordinates are as follows:

[0061]

[0062] In the next step, in actual data processing, before introducing control points during adjustment, the coordinates of the control points need to be verified. The reason for this is that the actual control points may be damaged due to natural or man-made reasons such as earthquakes and construction, so that some input control points are unavailable, that is, they cannot be fixed. This is very common in highly automated data processing systems. In this case, it is preferred to use N / M to measure the theoretical situation, and use n / M to measure the actual situation, as follows:

[0063] Step 120: Use a polygon algorithm to calculate the total number N of plots covered by at least one control point in all plots. Specifically, the inclusion relationship between the plots and all control points is calculated one by one. If a plot contains a control point, it can be considered that the plot has been covered.

[0064] Step 130: During the actual adjustment calculation, calculate the total number of plots n covered by at least one fixed control point in all plots. Specifically, the inclusion relationship between the plots and all control points is calculated plot by plot. If a plot contains a control point, it can be considered that the plot has been covered. It should be noted that this step is different from step 120. The calculation obtained in step 120 is theoretical, the number of plots covered by all control points, while step 130 obtains the number of plots covered by fixed control points during the actual adjustment calculation. These two steps are the relationship between the ideal situation and the actual situation.

[0065] Step 140: Calculate the coverage rate c1 of the selected control points based on the total number N of plots covered by at least one control point among all plots, and calculate the coverage rate c2 of the control points fixed during the actual adjustment based on the total number n of plots covered by at least one control point among all plots calculated during the actual adjustment, where c1=N / M, c2=n / M.

[0066] Step 150: Adjust the distribution uniformity of the control points according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

[0067] Coverage can be used to measure distribution uniformity and make timely adjustments to the uniformity.

[0068] For example, the threshold of coverage c1 can be set to 2, or 3, or other values. When the coverage c1 is less than the threshold, it can be considered that the distribution uniformity of the selected control points needs to be adjusted. On the other hand, the threshold of coverage c2 can be set to 2, or 3, or other values. When the coverage c2 is less than the threshold, it can be considered that the distribution uniformity of the selected control points needs to be adjusted. In other words, the control points need to be adjusted.

[0069] It should be pointed out that in the above example, the land parcel is divided into triangles. The advantages of this are: 1) it is easiest to use triangles when calculating whether a point falls within a polygon; 2) the polygons obtained by this division method will not cross the 0° or 180° meridian; 3) the area of ​​each triangle is roughly equal, ensuring that the calculation result is not distorted.

[0070] It can be understood that the above polygon segmentation method is exemplary and is not the only option. Other segmentation methods can also be applied, as long as the areas of the segmented polygons are roughly equal.

[0071] Preferably, the above examples can be implemented using programming languages ​​such as Python and JAVA, but the embodiments of the present application are not limited to a specific programming language.

[0072] Through the above embodiments, a method for evaluating the uniformity of control point distribution for use by a computer is proposed, wherein the control point coverage rate is used to measure the uniform distribution of the control points used in the network solution in the survey area.

[0073] The second embodiment of the present application relates to an evaluation system for the distribution of control points of a GNSS reference station network, and its structure is as follows: Figure 2 As shown, the evaluation system for the control point distribution of the GNSS reference station network includes:

[0074] A segmentation module is used to segment the survey area into M plots of equal area, where M is an integer greater than 1;

[0075] A first calculation module, configured to calculate a total number N of plots covered by at least one control point in the plot using a polygon algorithm;

[0076] The second calculation module is used to calculate the total number n of plots covered by at least one fixed control point in all plots during the actual adjustment calculation;

[0077] A first coverage rate calculation module is used to calculate the coverage rate c1 of the selected control point according to the total number N of plots covered by at least one control point in all plots, where c1=N / M;

[0078] The second coverage rate calculation module is used to calculate the coverage rate c2 of the fixed control points during the actual adjustment according to the total number n of plots covered by at least one control point in all plots calculated during the actual adjustment calculation, where c2=n / M;

[0079] The distribution uniformity adjustment module is used to adjust the distribution uniformity of the control points according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

[0080] Preferably, the number of plots is 1 / 5 to 1 / 6 of the total number of control points.

[0081] Preferably, the areas of the plots are equal.

[0082] Preferably, the plot of land is triangular.

[0083] The first implementation manner is a method implementation manner corresponding to the present implementation manner. The technical details in the first implementation manner can be applied to the present implementation manner, and the technical details in the present implementation manner can also be applied to the first implementation manner.

[0084] It should be noted that those skilled in the art should understand that the implementation functions of each module shown in the implementation of the above-mentioned GNSS reference station network control point distribution evaluation system can be understood with reference to the relevant description of the above-mentioned GNSS reference station network control point distribution evaluation method. The functions of each module shown in the implementation of the above-mentioned GNSS reference station network control point distribution evaluation system can be implemented by a program (executable instruction) running on a processor, or by a specific logic circuit. If the above-mentioned GNSS reference station network control point distribution evaluation system in the embodiment of the present application is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, ReadOnly Memory), disk or optical disk and other media that can store program codes. Thus, embodiments of the present application are not limited to any specific combination of hardware and software.

[0085] Accordingly, an embodiment of the present application further provides a computer storage medium, in which computer executable instructions are stored. When the computer executable instructions are executed by a processor, the various method embodiments of the present application are implemented.

[0086] In addition, the embodiment of the present application also provides an evaluation system for the distribution of control points of a GNSS base station network, which includes a memory for storing computer executable instructions, and a processor; the processor is used to implement the steps in the above-mentioned method implementations when executing the computer executable instructions in the memory. Among them, the processor can be a central processing unit (Central Processing Unit, referred to as "CPU"), or other general-purpose processors, digital signal processors (Digital Signal Processor, referred to as "DSP"), Application Specific Integrated Circuit (Application Specific Integrated Circuit, referred to as "ASIC"), etc. The aforementioned memory can be a read-only memory (read-only memory, referred to as "ROM"), a random access memory (random access memory, referred to as "RAM"), a flash memory (Flash), a hard disk or a solid-state hard disk, etc. The steps of the method disclosed in each embodiment of the present invention can be directly embodied as being executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0087] It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements. In the application documents of this patent, if it is mentioned that an action is performed according to an element, it means that the action is performed at least according to the element, which includes two situations: performing the action only according to the element, and performing the action according to the element and other elements. Expressions such as multiple, multiple, and multiple include 2, 2 times, 2 kinds, and more than 2, more than 2 times, and more than 2 kinds.

[0088] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A method for evaluating the distribution of control points of a GNSS reference station network, characterized in that: include: Divide the survey area into M plots of equal area, where M is an integer greater than 1; Calculate the total number N of plots in the plot that are covered by at least one control point using a polygon algorithm; During the actual adjustment calculation, the total number n of plots covered by at least one fixed control point among all plots is calculated; The coverage rate c1 of the selected control points is calculated based on the total number N of plots covered by at least one control point among all plots, and the coverage rate c2 of the control points fixed during the actual adjustment is calculated based on the total number n of plots covered by at least one control point among all plots obtained during the actual adjustment, where c1=N / M and c2=n / M.

2. The method according to claim 1, characterized in that Also includes: The distribution uniformity of the control points is adjusted according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

3. The method according to claim 1, characterized in that The number of the plots is 1 / 5 to 1 / 6 of the total number of control points.

4. The method according to claim 1, characterized in that The plots of land are equal in area.

5. The method according to claim 1, characterized in that In the step of dividing the survey area into a plurality of plots of equal area, a latitude and longitude grid is used to divide the survey area into a plurality of plots of equal area; and / or a map projection algorithm is used to divide the survey area into a plurality of plots of equal area using projected coordinates; and / or a discrete global grid system algorithm is used to generate plot boundaries.

6. The method according to claim 1, characterized in that In the step of dividing the survey area into a plurality of plots of equal area, the plots are triangles.

7. A GNSS reference station network control point distribution evaluation system, characterized in that: include: A segmentation module is used to segment the survey area into M plots of equal area, where M is an integer greater than 1; A first calculation module, configured to calculate a total number N of plots covered by at least one control point in the plot using a polygon algorithm; The second calculation module is used to calculate the total number n of plots covered by at least one fixed control point in all plots during the actual adjustment calculation; A first coverage rate calculation module is used to calculate the coverage rate c1 of the selected control point according to the total number N of plots covered by at least one control point in all plots, where c1=N / M; The second coverage rate calculation module is used to calculate the coverage rate c2 of the fixed control points during the actual adjustment according to the total number n of plots covered by at least one control point in all plots calculated during the actual adjustment calculation, where c2=n / M; The distribution uniformity adjustment module is used to adjust the distribution uniformity of the control points according to the coverage rate c1 of the control points and the coverage rate c2 of the control points fixed during the actual adjustment.

8. The system according to claim 7, characterized in that The number of the plots is 1 / 5 to 1 / 6 of the total number of control points.

9. The system according to claim 7, characterized in that The plots of land are equal in area.

10. The system according to claim 7, characterized in that The plot of land is triangular in shape.

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