Construction method and device of land-sea integrated coordinate framework control network

Abstract

The invention provides a land-sea integrated coordinate framework control network construction method and device, and relates to the technical field of land-sea integrated area coordinate framework construction, and the method comprises the steps: obtaining the distribution information of pre-established reference stations in a target area; dividing the target area into a preset number of grids based on the distribution information; counting the total number of the reference stations contained in each grid, and distributing probability information for the reference stations in each grid; selecting candidate reference stations from at least one grid containing the reference stations based on the probability information; and determining the candidate reference station meeting the screening standard as a target reference station, so as to construct the land-sea integrated coordinate framework control network based on the target reference station. According to the construction method and device of the land-sea integrated coordinate frame control network, the land-sea integrated coordinate frame consistent with the current land coordinate reference can be effectively refined, and centimeter-level coordinate reference service consistent with the land is provided for offshore high-precision navigation and positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of land-sea integrated regional coordinate frame construction, and in particular to a method and device for constructing a land-sea integrated coordinate frame control network. Background Art

[0002] Regional coordinate frames are widely used in surface change monitoring such as high-precision deformation monitoring, natural resource change monitoring, and various disaster monitoring. Compared with the global reference frame, the regional reference frame is more complicated in terms of the impact of various regional dynamic environmental factors on the reference frame. Therefore, the refinement of the regional coordinate frame is not only affected by tectonic movement, but also by the nonlinear impact of complex dynamic environments such as atmosphere, land water, and sea level changes. These impacts vary greatly in different regions or on different time scales.

[0003] As an offshore extension of the land coordinate frame, the integrated land-sea regional coordinate frame needs to be based on the current geodetic coordinate system definition and its reference frame. By laying out control networks on remote islands and reefs and offshore targets, the point coordinates of these framework points in the current geodetic coordinate system are obtained through data processing. In order to maintain and refine the framework, it is also necessary to add velocity field information to these geodetic control points, and the velocity field accuracy should reach the accuracy level of land base stations.

[0004] At present, due to the sparse and uneven distribution of distant islands and reefs, as well as the poor accuracy of long-distance transmission of distant sea benchmarks, it is difficult to construct an integrated land and sea regional coordinate framework, and it is also difficult to achieve accurate positioning over ultra-long distances in the distant sea. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a method and device for constructing a land-sea integrated coordinate frame control network to alleviate the above-mentioned technical problems.

[0006] In a first aspect, an embodiment of the present invention provides a method for constructing a land-sea integrated coordinate frame control network, the method comprising: obtaining distribution information of pre-established reference stations in a target area, wherein the target area comprises a pre-divided land and sea area; dividing the target area into a preset number of grids based on the distribution information; counting the total number of reference stations contained in each of the grids, and assigning probability information to the reference stations in each of the grids; wherein the probability information is used to characterize the probability that the reference station is determined as a site of the land-sea integrated coordinate frame control network; based on the probability information, selecting a preset number of candidate reference stations from at least one of the grids containing the reference station according to a preset random algorithm; determining a preset number of the candidate reference stations that meet the preset screening criteria as target reference stations, so as to construct the land-sea integrated coordinate frame control network based on the target reference stations.

[0007] In combination with the first aspect, an embodiment of the present invention provides a first possible implementation of the first aspect, wherein the step of dividing the target area into a preset number of grids based on the distribution information includes: determining the total number of the base stations deployed in the target area based on the distribution information; calculating the number of the grids according to the total number, so as to divide the target area into a plurality of grids according to longitude and latitude based on the number of grids.

[0008] In combination with the first aspect, an embodiment of the present invention provides a second possible implementation of the first aspect, wherein the above-mentioned step of assigning probability information to the reference station in each of the grids includes: determining a first probability of the reference station based on an observation quality factor of the reference station, wherein the first probability is used to characterize the accuracy of the reference station; determining the probability information of each of the reference stations based on the first probability and the number of the grids containing the reference station.

[0009] In combination with the first aspect, an embodiment of the present invention provides a third possible implementation of the first aspect, wherein the step of selecting a preset number of candidate base stations from at least one grid containing the base station according to a preset random algorithm comprises: taking the total number of base stations contained in each of the grids as the total sample, and based on the probability information, repeatedly selecting a preset number of candidate base stations from at least one grid containing the base station according to a preset random algorithm until the number of repetitions reaches a preset number threshold; and storing the candidate base stations selected each time in a pre-constructed base station list.

[0010] In combination with the third possible implementation of the first aspect, an embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the above-mentioned step of determining a preset number of candidate reference stations that meet the preset screening criteria as target reference stations includes: calculating a distribution index corresponding to the preset number of candidate reference stations, wherein the distribution index is used to measure the uniform distribution degree of the preset number of candidate reference stations; if the distribution index reaches a preset minimum threshold, it is determined that the preset number of candidate reference stations meets the screening criteria; and the preset number of candidate reference stations are determined as the target reference stations.

[0011] In combination with the first aspect, an embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the above method also includes: responding to a positioning service request, obtaining the position information of the maritime target based on the integrated land and sea coordinate frame control network; obtaining at least one pre-configured error correction model; correcting the position information based on at least one of the error correction models; wherein the error correction model includes at least one of the following models: an ionospheric multi-frequency combination elimination model, a tropospheric delay partition modeling, and a tidal error partition correction model.

[0012] In combination with the first aspect, an embodiment of the present invention provides a sixth possible implementation of the first aspect, wherein the above method also includes: analyzing the correlation between the target reference stations included in the land and sea integrated coordinate frame control network; selecting a preset number of related reference stations from the target reference stations included in the land and sea integrated coordinate frame control network based on the correlation; calculating the common mode errors of the preset number of related reference stations to correct the accuracy of the land and sea integrated coordinate frame control network based on the common mode error.

[0013] In combination with the sixth possible implementation of the first aspect, an embodiment of the present invention provides a seventh possible implementation of the first aspect, wherein the step of analyzing the correlation between the target reference stations included in the land-sea integrated coordinate frame control network comprises: calculating the correlation coefficient between the target reference stations based on the time series information of the target reference stations included in the land-sea integrated coordinate frame control network; the step of selecting a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation comprises: selecting at least one of the target reference stations whose correlation coefficient is higher than a preset coefficient threshold as a related reference station.

[0014] In a second aspect, an embodiment of the present invention further provides a device for constructing a land-sea integrated coordinate frame control network, the device comprising: an acquisition module, used to acquire distribution information of pre-established reference stations in a target area, wherein the target area comprises a pre-divided land and sea area; a division module, used to divide the target area into a preset number of grids based on the distribution information; a statistical module, used to count the total number of reference stations contained in each of the grids, and to assign probability information to the reference stations in each of the grids; wherein the probability information is used to characterize the probability of the reference station being determined as a site of the land-sea integrated coordinate frame control network; a selection module, used to select a preset number of candidate reference stations from at least one of the grids containing the reference stations according to a preset random algorithm based on the probability information; a construction module, used to determine a preset number of the candidate reference stations that meet the preset screening criteria as target reference stations, so as to construct the land-sea integrated coordinate frame control network based on the target reference stations.

[0015] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0016] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and the computer program is executed by a processor to perform the steps of the method described in the first aspect.

[0017] The embodiments of the present invention bring the following beneficial effects: The method and device for constructing a land-sea integrated coordinate frame control network provided by an embodiment of the present invention can obtain the distribution information of pre-established reference stations in a target area; divide the target area into a preset number of grids based on the distribution information; count the total number of reference stations contained in each grid, and assign probability information to the reference stations in each grid; based on the probability information, select a preset number of candidate reference stations from at least one grid containing reference stations according to a preset random algorithm; determine the preset number of candidate reference stations that meet the preset screening criteria as target reference stations, so as to construct a land-sea integrated coordinate frame control network based on the target reference stations, thereby achieving the consistency of the coordinate references between land and sea, and can effectively refine the land-sea integrated coordinate frame that is consistent with the current coordinate reference on land, and provide centimeter-level coordinate reference services that are consistent with land for high-precision navigation and positioning at sea.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A flow chart of a method for constructing a land-sea integrated coordinate frame control network provided by an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a device for constructing a land-sea integrated coordinate frame control network provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] At present, in the regional coordinate framework of the open sea and the land, the following two issues need to be further studied: (1) How to construct a coordinate frame control network when remote islands and reefs are sparse and unevenly distributed?

[0024] Generally, unlike the terrestrial coordinate frame control network, in the offshore area, the islands and reefs available for the deployment of reference stations are sparse and unevenly distributed. Some areas have relatively dense islands and reefs, while some areas have no islands and reefs available for the deployment of reference stations. Therefore, how to select reference stations in the offshore area to build a coordinate frame control network is a basic problem and an important difficulty in building a consistent coordinate frame for land and sea.

[0025] (2) The problem of poor accuracy in long-distance transmission of offshore benchmarks.

[0026] Usually, the distance between the offshore reference station and the land reference station is far, and the reference transfer is greatly affected by the marine atmosphere, ionosphere, and ocean tides, which affects the accuracy of the offshore reference. Therefore, relevant technologies have proposed the issue of refining the stratosphere, ionosphere, and ocean tide models under different ocean environments, which is also a key difficulty in the construction of an integrated land and sea coordinate reference.

[0027] Based on this, an embodiment of the present invention provides a method and device for constructing a land-sea integrated coordinate framework control network, in the hope of providing a technical method for a land-sea integrated coordinate reference.

[0028] To facilitate understanding of this embodiment, a method for constructing a land-sea integrated coordinate frame control network disclosed in an embodiment of the present invention is first introduced in detail.

[0029] In a possible implementation, an embodiment of the present invention provides a method for constructing a land-sea integrated coordinate frame control network, wherein the land-sea integrated coordinate frame control network in the embodiment of the present invention is also referred to as a control network hereinafter.

[0030] Specifically, Figure 1 The flowchart of a method for constructing a land-sea integrated coordinate frame control network shown in FIG. 1 includes the following steps: Step S102, obtaining distribution information of pre-established reference stations in the target area; Among them, the target area in the embodiment of the present invention includes pre-divided land and sea areas, such as land coasts, islands and reefs, and marine targets (such as offshore platforms, etc.) within a certain range.

[0031] Furthermore, the reference station in the embodiment of the present invention refers to a GNSS (Global Navigation Satellite System) reference station for continuous observation in a target area, such as a land coast, an island reef, and a marine target (such as an offshore platform, etc.).

[0032] In actual use, the land-sea integrated coordinate frame control network in the embodiment of the present invention is actually also a regional coordinate frame. The overall idea of ​​refining the land-sea integrated coordinate frame is to use the GNSS reference stations that are continuously observed on the land coast, islands and reefs, and offshore targets (offshore platforms, etc.) to build a coordinate frame reference station control network (hereinafter referred to as the control network). Through GNSS positioning data processing and analysis, the three-dimensional coordinates of the control network reference station under the current coordinate reference of my country are finally obtained. Then, after the epoch is reduced using the velocity field model of the reference station, it is estimated with the land reference station, island reference station and offshore target station at a specific reference epoch, and the coordinate set of each reference station in the land-sea integrated coordinate frame control network at the reference epoch can be obtained.

[0033] Furthermore, the method for constructing a land-sea integrated coordinate frame control network provided in an embodiment of the present invention fully utilizes and considers the GNSS reference station network of coastal land and islands, realizes the optimal design of the reference station through the grid control method, and finally constructs a land-sea integrated coordinate frame control network.

[0034] Specifically, the grid control method includes the following process of steps S104 to S108.

[0035] Step S104, dividing the target area into a preset number of grids based on the distribution information; The distribution information in the embodiment of the present invention refers to the distribution information of all reference stations included in the target area, such as the position of each reference station and the total number of all reference stations.

[0036] Step S106, counting the total number of reference stations included in each grid, and allocating probability information to the reference stations in each grid; The probability information in the embodiment of the present invention is used to characterize the probability that the reference station is determined as a site of the land-sea integrated coordinate frame control network.

[0037] In actual use, when allocating probability information to the base station in each grid, the stability and observation quality of the base station are considered as important factors to ensure the accuracy of the final constructed land and sea integrated coordinate frame control network.

[0038] Step S108, selecting a preset number of candidate reference stations from at least one grid including the reference station according to a preset random algorithm based on the probability information; Step S110 , determining a preset number of candidate reference stations that meet a preset screening criterion as target reference stations, so as to construct a land-sea integrated coordinate frame control network based on the target reference stations.

[0039] In actual use, the base stations in land and sea areas are unevenly distributed, for example, there are more base stations on land, and fewer base stations on islands and reefs. The land-sea integrated coordinate framework control network constructed in the embodiment of the present invention is composed of GNSS continuous observation base stations established on land, islands and reefs, and offshore platforms and other offshore targets. Therefore, in the embodiment of the present invention, it is necessary to select appropriate base stations as the control network, and each base station in the control network can also be called a framework point. In order to avoid the problem of base offset caused by the concentration of framework points in a certain area, therefore, in the embodiment of the present invention, it is necessary to control the position of the base station as a whole, thereby improving the full-area solution optimization capability, that is, based on the above-mentioned steps S104~S108, the screening of base stations and the construction of the control network are realized.

[0040] Specifically, after obtaining the distribution information of the base stations, the embodiment of the present invention can determine the total number of base stations deployed in the target area based on the distribution information when dividing the grids; then calculate the number of grids based on the total number, so as to divide the target area into multiple grids according to longitude and latitude based on the number of grids.

[0041] In actual use, the above-mentioned grid division process is actually a process of evenly partitioning the target area according to longitude and latitude to obtain multiple grids, and then counting the number and quality of GNSS reference stations in each grid to facilitate the final distribution of probability information.

[0042] In specific implementation, the size of each grid can be calculated according to the following formula, and then the target area can be divided according to longitude and latitude to obtain multiple grids of the following size JW:

[0043] Where JW represents the size of the latitude and longitude grid; N is the total number of base stations deployed in the target area.

[0044] Furthermore, in the above embodiment of the present invention, when allocating probability information to the reference station in each grid, the stability and observation quality of the reference station are taken as important factors affecting the accuracy of the control network.

[0045] Therefore, the target reference station selected in the embodiment of the present invention needs to consider factors such as its station stability and the quality of GNSS observation data, so as to assign different probabilities to each reference station to ensure that the reference station with high accuracy has a high probability of being the framework point of the control network.

[0046] Specifically, in an embodiment of the present invention, when probability information is assigned to a reference station in each grid, it is necessary to first determine a first probability of the reference station based on the observation quality factor of the reference station, wherein the first probability is used to characterize the accuracy of the reference station; and then determine the probability information of each reference station based on the first probability and the number of grids containing the reference station.

[0047] The first probability in the embodiment of the present invention can be expressed as the following formula:

[0048] in, ; In the formula, , , It represents the mean error of the base station coordinates in the x, y, and z directions, which can be obtained based on the historical observation records of the base station. is the probability value of the jth reference station in a single grid, that is, the first probability in the embodiment of the present invention; n is the number of reference stations in each grid. The larger the number of reference stations in the grid, the smaller the first probability of a single reference station.

[0049] Further, the above probability information in the embodiment of the present invention is expressed as:

[0050] Where num_block represents the number of grids containing the base station. Represents the probability information of reference station i.

[0051] Furthermore, in an embodiment of the present invention, based on the above-mentioned probability information, when selecting candidate base stations, the total number of base stations contained in each grid needs to be used as the total sample, and based on the probability information, a preset number of candidate base stations is repeatedly selected from at least one grid containing the base stations according to a preset random algorithm until the number of repetitions reaches a preset threshold; and the candidate base stations selected each time are stored in a pre-constructed base station list.

[0052] In actual use, the above random algorithm needs to be executed multiple times. Each time it is executed, a set of preset number of candidate base stations can be obtained. After repeated execution of the random algorithm, multiple sets of preset number of candidate base stations are actually obtained. Then, one set is further selected from the multiple sets of candidate base stations as the target base station, thereby constructing an integrated land and sea coordinate frame control network.

[0053] In specific implementation, S represents the total sample including all reference stations, and N reference stations are selected from S as a group of candidate reference stations according to the following random algorithm: select_list=randsrc(N,1,[S;F]) Wherein, F is a matrix vector containing probability information of all reference stations, which is composed of the above Fi, randsrc is an algorithm for selecting N reference stations from the total sample S according to the probability of F, and select_list is a list of reference stations. The random selection test is repeated K times, that is, the number threshold is K. The number threshold can be customized, for example, the number of random tests can be referenced to 10,000 times, and can be set according to actual usage, and the embodiment of the present invention does not limit this.

[0054] By repeated random experiments of the above random algorithm, a large number of candidate reference station configurations can be obtained, and then through spatial screening, the optimal reference station distribution configuration can be obtained, that is, the above target reference station can be obtained.

[0055] Specifically, in an embodiment of the present invention, when screening target reference stations, a distribution index corresponding to each group of a preset number of candidate reference stations can be calculated, wherein the distribution index is used to measure the uniform distribution degree of the preset number of candidate reference stations; if the distribution index reaches a preset minimum threshold, it is determined that the preset number of candidate reference stations meets the screening criteria; and the preset number of candidate reference stations are determined as target reference stations.

[0056] In actual use, the GDOP (Geometric dilution of precision) value can be used as a distribution index in the embodiment of the present invention. When the reference points are evenly distributed, the GDOP value of the geometric center position of the control network reaches a minimum value. For this purpose, the GDOP value of a preset number of reference stations to the center of the earth in each group of candidate reference stations can be calculated as an index to measure the degree of uniform distribution of the reference stations. For example, the smaller the GDOP value, the more evenly the reference stations are distributed. At this time, the land-sea integrated coordinate frame control network is the optimal reference station distribution control network, and the coordinate reference accuracy is the highest.

[0057] Among them, the following formula gives a calculation formula for the GDOP value:

[0058] in, , ; ; And, where A is the space coordinate matrix, ( ) represent the spatial coordinate values ​​of the Nth reference station, S represents the median of the sum of errors of all reference stations, tr represents the sum of the elements on the diagonal of the matrix, represents the weight of each group of reference stations, and T here represents the transpose of the matrix.

[0059] It should be understood that the above GDOP value calculation formula is a preferred method, and in other implementations, it can be modified according to actual usage, and the embodiment of the present invention is not limited to this.

[0060] Furthermore, based on the above-mentioned land-sea integrated coordinate frame control network constructed in the embodiment of the present invention, it is an optimal reference station distribution control network, and its GNSS long baseline accurate solution is the key technology to realize the transfer of land to offshore reference. Therefore, in the embodiment of the present invention, the above-mentioned land-sea integrated coordinate frame control network constructed mostly uses double-difference carrier phase observations for high-precision positioning. However, in the medium and long baseline measurement, this method is easily affected by various environmental errors, and the positioning accuracy loss is large. In addition, considering the land and sea areas in the embodiment of the present invention, the land-sea integrated coordinate frame control network constructed by the embodiment of the present invention, in the double-difference carrier phase observation equation, the influencing errors are mainly ionospheric delay, tropospheric delay, multipath effect and observation noise.

[0061] Therefore, in the embodiment of the present invention, a method is proposed to achieve high-precision reference transmission over ultra-long distances in the open sea through ionosphere correction in the open sea, zoning modeling of the error impact of the troposphere in the marine environment, and zoning modeling of the error impact of sea tides.

[0062] Specifically, in an embodiment of the present invention, the following processes are also included: responding to a positioning service request, obtaining the location information of a maritime target based on the land-sea integrated coordinate frame control network; obtaining at least one pre-configured error correction model; correcting the location information based on at least one error correction model; wherein the error correction model includes at least one of the following models: an ionospheric multi-frequency combination elimination model, a tropospheric delay partition modeling, and a tidal error partition correction model.

[0063] In actual use, the advantages of the current three-frequency GNSS signal are mostly used, and the ionospheric delay error is weakened by the combined observation value of the multi-frequency GNSS receiver; however, the double difference residual of the atmospheric error is large in the ultra-long distance and complex environment of the open sea, and it is necessary to construct the tropospheric delay partition modeling according to the environmental characteristics; and in the marine environment, different sea areas need to establish corresponding tide error partition correction models to improve the solution accuracy. Therefore, in the embodiment of the present invention, the above error correction model is established in the following way: (1) Ionospheric multi-frequency combination elimination model: Generally, the ionosphere is the atmospheric layer between about 50km and 1000km above the ground. With the continuous improvement of Beidou signals, the application of multi-frequency will change the traditional dual-frequency navigation and positioning mode. Applying multi-frequency to the ionospheric refraction error can correct the high-order items, and the positioning accuracy of the multi-frequency combination will be conducive to solving high-precision ultra-long baselines. The combination of three frequencies and above can effectively eliminate the high-order items of the ionosphere.

[0064] By using three frequencies to eliminate the high-order terms of the ionospheric refraction error, since one more observation quantity is added, the ionospheric refraction error can be corrected to the second-order term. The specific expression formula is as follows: , i=1,2,3; in, represents the error after combination, represents the group refractive index, represents the phase refractive index, f is the carrier frequency, and i represents the i-th carrier signal (i=1,2,3); , , Respectively , , The distance from the observation station to the satellite is obtained by synchronous observation of electromagnetic waves. , A1 and A2 are design matrices, and their specific formulas are as follows:

[0065]

[0066] The solution is:

[0067]

[0068]

[0069] This formula is the ionospheric delay distance correction of the triple-frequency carrier phase observation value and the code phase observation value to the second-order term, and based on this correction term, the positioning service of the integrated land and sea coordinate frame control network can be corrected.

[0070] (2) Tropospheric delay partition modeling: Generally, high-precision spatial tropospheric correction information is one of the key parameters to improve the accuracy of the solution. Moreover, the tropospheric delay includes the tropospheric dry delay (dry component) and the tropospheric wet delay (wet component).

[0071] In an embodiment of the present invention, based on the tropospheric delay extraction and modeling technology of the real-time large-scale Beidou / GNSS encrypted network, a fast extraction and analysis method of multi-scale tropospheric delay is constructed to achieve the correction of tropospheric delay.

[0072] First, let’s look at the mathematical function design for tropospheric delay partition modeling: The original tropospheric information wet delay component (wet component) has a large difference in elevation between the land and island reference stations, so it is necessary to extrapolate the wet delay component at the corresponding height to the elevation where the ellipsoid height is 0. Since water vapor changes exponentially with height, the vertical extrapolation formula for the wet delay component can be expressed as follows:

[0073] in, It represents the zenith delay corresponding to the reference station with a geodetic height of h, is the zenith wet delay corresponding to the ellipsoid height of 0, Indicates the base station geodetic height, is the elevation correction parameter; and It can be obtained by the following formula: ; Among them, doy (day of year) represents the seasonal variation of zenith delay, and the coefficient It can be obtained from atmospheric observation data and reanalysis data.

[0074] Furthermore, the wet component of the tropospheric delay of the reference station in the fusion region is integrated to generate the spherical harmonic function representing the wet component of the tropospheric delay in the region (the ellipsoid height is 0), which is in the following form:

[0075] in, Indicates the tropospheric point Tropospheric delay at ; and denote the latitude and longitude of the troposphere, respectively; represents the maximum degree of spherical harmonics; represents the normalized Legendre function of degree n and order m; Represents the normalization function, as shown below; and They represent the model parameters to be estimated.

[0076]

[0077] (3) Tidal error zone correction model: According to Farrell theory, the formula for calculating tidal load is usually:

[0078] Where L represents the tidal load, θ, λ are the coordinates of the calculation point, t represents the calculation time, θ′, λ′ are the coordinates of the load point, ψ, A are the angular distance and azimuth from the calculation point to the load point, is the density of seawater, R is the radius of the earth, H(θ′, λ′, t) is the instantaneous tidal height at (θ′, λ′), SG is the entire sea surface, G( , A) is the combination of displacement load Green's function and azimuth angle.

[0079] When considering the offshore tidal effect, the corresponding area in the global tidal model must be replaced by the offshore tidal model. Therefore, the above formula for calculating tidal loads is corrected to:

[0080] H L (θ′, λ′, t) represents the instantaneous tidal height of the offshore area L.

[0081] Usually, the above calculation process is completed in the frequency domain, and the total load effect is the superposition of different tidal waves, which can be expressed as:

[0082] Where i represents the i-th reference station, They are The amplitude, angular frequency and phase of x0 are the initial phase of astronomical amplitude. For displacement, it includes horizontal and vertical components. The accuracy of global tidal models in offshore areas, especially near coastlines and bays, is relatively poor, so high-resolution and high-precision offshore tidal data are needed to compensate.

[0083] In practical applications, the station displacement correction caused by tidal load can be performed by each tidal wave, that is, the radial, east-west and north-south amplitudes of the tidal wave corresponding to a station can be calculated by the tidal wave chart and Green's function. and the phase lag relative to the Greenwich meridian , and finally corrected to the superposition of various tidal waves, expressed as the following formula

[0084] In the formula and is the frequency of the tidal wave and the astronomical amplitude at the epoch time, It is the universal time in seconds, currently only the 11th order is considered.

[0085] In actual use, for the above error correction models, in actual positioning services, one or more error correction models can be adopted to correct positioning information according to actual usage requirements. The specific method is subject to actual usage and is not limited in this embodiment of the present invention.

[0086] Furthermore, in addition to the above-mentioned error correction models, the embodiment of the present invention also includes a unified adjustment strategy for the land-sea integrated coordinate frame control network. This is because the land-sea integrated coordinate frame control network constructed in the embodiment of the present invention covers the land coast, some islands and reefs, and offshore targets. Therefore, in order to obtain high-precision unified frame point coordinates and take into account the differences in the time span of the observation data, the geographical environment of the survey area, and the climatic conditions, the following adjustment strategy can be adopted: ① Unification of adjustment datum. In order to reduce the accuracy loss during data processing, when the control network is adjusted as a whole, after selecting the coordinate frame and reference epoch, the GNSS observations of each epoch are converted to the same reference epoch of the same reference frame.

[0087] ② When GNSS is solved for a single day, the principle of partition solution is adopted. Each zone generally does not exceed 40 stations, which is called a subnet. System error compensation between subnets. In order to reduce the systematic errors existing in each subnet (including benchmark system errors, observation system errors, instrument system errors, orbit and ephemeris system errors, crustal deformation system errors, etc.), scale parameters and rotation parameters are introduced to the baseline vectors of each subnet in the adjustment of the entire control network. 1 scale parameter is used to eliminate the possible scaling relationship between subnets, and the rotation parameters include 3 rotation angle parameters around the X, Y, and Z axes to eliminate the differences between subnets in different directions. An adjustment model with systematic error parameters is used to ensure the consistency of the adjustment benchmarks of each subnet.

[0088] ③ Abnormal error impact control. Before adjusting the entire control network, each synchronous observation area needs to be detected for abnormal errors. If the standardized residual is greater than 3 times the mean error, the observation is a suspected abnormal observation, and the corresponding synchronous observation area can be temporarily excluded from the adjustment calculation. After that, the robust estimation theory can be considered for parameter estimation.

[0089] ④ Compensation for random model errors in the synchronous observation area and each subnet. The nominal accuracy of each subnet generally has random model errors. In order to control the impact of random model errors on the adjustment results of the overall control network, variance component estimation can be used to re-estimate the accuracy and weight of each subnet observation in the adjustment of each synchronous area subnet and the final adjustment of the overall control network.

[0090] By uniformly adjusting the reference stations or framework points of the control network distributed on land, islands and reefs and on the sea, the precise coordinates of the framework points of the unified coordinate reference can be obtained.

[0091] Furthermore, in the embodiment of the present invention, the refinement and maintenance of the land-sea integrated coordinate frame control network is also considered. Generally, a high-precision coordinate frame must consider the maintenance of the frame, that is, it is necessary to ensure the continuous refinement of the coordinates and speed of the reference station according to a certain re-survey strategy. In the embodiment of the present invention, a method is proposed to extract the common mode error in the land-sea integrated coordinate frame control network by zoning, thereby improving the accuracy of the GNSS velocity field, ensuring the consistency of the accuracy of the land-sea integrated coordinate frame control network.

[0092] Specifically, the refined maintenance strategy in the embodiment of the present invention is as follows: Analyze the correlation between the target reference stations included in the land-sea integrated coordinate frame control network; select a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation; calculate the common mode errors of the preset number of related reference stations to correct the accuracy of the land-sea integrated coordinate frame control network based on the common mode errors.

[0093] Specifically, when analyzing the correlation, the correlation coefficient between each target reference station can be calculated based on the time series information of the target reference stations included in the integrated land and sea coordinate frame control network; based on the correlation coefficient, when selecting the relevant reference station, at least one target reference station with a correlation coefficient higher than a preset coefficient threshold can be selected as the relevant reference station.

[0094] Among them, the above correlation analysis mainly considers that the common mode error is mainly caused by non-structural loads on the surface such as the atmosphere and water bodies, and the differences in land and ocean environments lead to large differences in spatial correlations between reference stations. Therefore, in the embodiment of the present invention, the correlation between reference stations can be analyzed by calculating the correlation coefficient.

[0095] Usually, the correlation coefficient is expressed as It is represented by the residual time series corresponding to the coordinate components of the two reference stations ( and ) is calculated based on the common epoch of the year, and the formula is as follows:

[0096] Where: is the number of common epochs between reference stations, i.e., the length of the time series, k represents the kth epoch, represents the residual value corresponding to the two reference stations at the kth epoch, are the means of the residual time series of the two GNSS reference stations.

[0097] Furthermore, after obtaining the above correlation coefficients, the correlation coefficients can be sorted, for example, sorted from large to small, and then the target reference station corresponding to the correlation coefficient being higher than the preset coefficient threshold is selected as the relevant reference station. At this time, the selected relevant reference station is a station with strong correlation and can be used as a partition to extract the common mode error.

[0098] For example, assuming the number of base stations is , the observation time span is , we can create a dimension The matrix , if the matrix Tiandi The coordinate residual value of a station (reference station) is expressed as , represents the i-th day, represents the jth reference station, then the common mode error of the observation network can be expressed as:

[0099] in, Representative Tiandi The mean error corresponding to each measuring station.

[0100] By extracting the common mode errors of the base station network in different partitions, the influence of the ocean environment on the GNSS solution can be effectively eliminated, the accuracy of the base station velocity field can be improved, and the accuracy of the coordinate frame in the far sea area can be ensured to be equivalent to that on land.

[0101] Therefore, in the embodiment of the present invention, the land-sea integrated coordinate frame control network constructed by GNSS reference stations established on land, islands and reefs, and offshore targets (such as offshore platforms, etc.) can achieve the consistency of land and sea coordinate references. In addition, the grid control method is introduced to optimize the reference station to ensure the optimal configuration of the control network and avoid excessive concentration of framework points; through the integrated adjustment strategy, a unified reference frame and a unified reference epoch are achieved for the control network points in the land and sea regions; using the ionosphere elimination technology, an ionosphere multi-frequency combination elimination model, a tropospheric delay partition modeling, and a tide error partition correction model are constructed to achieve ultra-long-distance benchmark transmission in the open sea; finally, a common mode error extraction strategy that adapts to the characteristics of the regional dynamic environment is proposed to improve the velocity field accuracy of the reference station, providing a guarantee for maintaining the accuracy of the land-sea integrated coordinate frame control network.

[0102] Therefore, the method for constructing the integrated land and sea coordinate frame control network provided by the embodiment of the present invention can effectively refine the regional integrated land and sea coordinate frame that is consistent with the current land coordinate reference, and provide centimeter-level coordinate reference services consistent with the land for high-precision navigation and positioning at sea.

[0103] Furthermore, the embodiment of the present invention also provides a device for constructing a land-sea integrated coordinate frame control network, such as Figure 2 A schematic diagram of a structure of a device for constructing a land-sea integrated coordinate frame control network is shown, the device comprising: An acquisition module 20 is used to acquire distribution information of pre-established reference stations in a target area, wherein the target area includes a pre-divided land and sea area; A division module 22, configured to divide the target area into a preset number of grids based on the distribution information; A statistical module 24 is used to count the total number of reference stations contained in each of the grids, and to assign probability information to the reference stations in each of the grids; wherein the probability information is used to characterize the probability that the reference station is determined as a station of the land-sea integrated coordinate frame control network; A selection module 26, configured to select a preset number of candidate reference stations from at least one of the grids including the reference station according to a preset random algorithm based on the probability information; The construction module 28 is used to determine a preset number of the candidate reference stations that meet the preset screening criteria as target reference stations, so as to construct the land-sea integrated coordinate frame control network based on the target reference stations.

[0104] Furthermore, the step of dividing the target area into a preset number of grids based on the distribution information includes: The total number of the reference stations deployed in the target area is determined based on the distribution information; the number of the grids is calculated according to the total number, so as to divide the target area into a plurality of grids according to longitude and latitude based on the number of grids.

[0105] Furthermore, the above-mentioned step of assigning probability information to the reference station in each of the grids includes: determining a first probability of the reference station based on an observation quality factor of the reference station, wherein the first probability is used to characterize the accuracy of the reference station; and determining the probability information of each of the reference stations based on the first probability and the number of the grids containing the reference station.

[0106] Furthermore, the step of selecting a preset number of candidate reference stations from at least one of the grids including the reference station according to a preset random algorithm based on the probability information includes: Taking the total number of reference stations contained in each of the grids as the total sample, based on the probability information, repeatedly selecting a preset number of candidate reference stations from at least one of the grids containing the reference stations according to a preset random algorithm until the number of repetitions reaches a preset threshold number; and storing the candidate reference stations selected each time in a pre-constructed reference station list.

[0107] Among them, the step of determining a preset number of candidate reference stations that meet the preset screening criteria as target reference stations includes: calculating a distribution index corresponding to the preset number of candidate reference stations, wherein the distribution index is used to measure the uniform distribution degree of the preset number of candidate reference stations; if the distribution index reaches a preset minimum threshold, it is determined that the preset number of candidate reference stations meets the screening criteria; and, the preset number of candidate reference stations are determined as the target reference stations.

[0108] Furthermore, the above device is also used for: In response to a positioning service request, the position information of the maritime target is obtained based on the integrated land-sea coordinate frame control network; at least one pre-configured error correction model is obtained; and the position information is corrected based on at least one of the error correction models; wherein the error correction model includes at least one of the following models: an ionospheric multi-frequency combination elimination model, a tropospheric delay partition modeling, and a tidal error partition correction model.

[0109] Furthermore, the above device is also used for: Analyze the correlation between the target reference stations included in the land-sea integrated coordinate frame control network; select a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation; calculate the common mode errors of the preset number of related reference stations to correct the accuracy of the land-sea integrated coordinate frame control network based on the common mode errors.

[0110] The step of analyzing the correlation between the target reference stations included in the land-sea integrated coordinate frame control network includes: calculating the correlation coefficients between the target reference stations based on the time series information of the target reference stations included in the land-sea integrated coordinate frame control network; The step of selecting a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation includes: selecting at least one of the target reference stations whose correlation coefficient is higher than a preset coefficient threshold as a related reference station.

[0111] The device for constructing a land-sea integrated coordinate frame control network provided in an embodiment of the present invention has the same technical features as the method for constructing a land-sea integrated coordinate frame control network provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0112] Furthermore, an embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are executed.

[0113] Furthermore, an embodiment of the present invention also provides a structural diagram of an electronic device, such as Figure 3 As shown, it is a schematic diagram of the structure of the electronic device, wherein the electronic device includes a processor 31 and a memory 30, the memory 30 stores computer executable instructions that can be executed by the processor 31, and the processor 31 executes the computer executable instructions to implement the above method.

[0114] exist Figure 3In the illustrated embodiment, the electronic device further includes a bus 32 and a communication interface 33 , wherein the processor 31 , the communication interface 33 and the memory 30 are connected via the bus 32 .

[0115] Among them, the memory 30 may include a high-speed random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 33 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. can be used. The bus 32 can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus 32 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0116] The processor 31 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit in the processor 31 or the instruction in the form of software. The above processor 31 can be a general 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 gates or transistor logic devices, discrete hardware components. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiment of the present invention can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor 31 reads the information in the memory and completes the above method in combination with its hardware.

[0117] The computer program product of the method and device for constructing an integrated land-sea coordinate frame control network provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the previous method embodiments. The specific implementation can be found in the method embodiments, which will not be repeated here.

[0118] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0119] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0120] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0121] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0122] Finally, it should be noted that the above embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for constructing a land-sea integrated coordinate frame control network, characterized in that: The method comprises: Acquiring distribution information of pre-established reference stations in a target area, wherein the target area includes a pre-divided land and sea area; Dividing the target area into a preset number of grids based on the distribution information; Counting the total number of reference stations contained in each of the grids, and assigning probability information to the reference stations in each of the grids; wherein the probability information is used to characterize the probability that the reference station is determined as a station of the land-sea integrated coordinate frame control network; Based on the probability information, selecting a preset number of candidate reference stations from at least one of the grids including the reference station according to a preset random algorithm; A preset number of the candidate reference stations that meet a preset screening criterion are determined as target reference stations, so as to construct the land-sea integrated coordinate frame control network based on the target reference stations.

2. The method according to claim 1, characterized in that The step of dividing the target area into a preset number of grids based on the distribution information comprises: Determine the total number of the reference stations deployed in the target area based on the distribution information; The number of the grids is calculated according to the total number, so as to divide the target area into a plurality of the grids according to longitude and latitude based on the number of the grids.

3. The method according to claim 1, characterized in that The step of allocating probability information to each of the reference stations in the grid comprises: Determine a first probability of the reference station according to an observation quality factor of the reference station, wherein the first probability is used to characterize the accuracy of the reference station; Probability information of each of the reference stations is determined based on the first probability and the number of the grids containing the reference stations.

4. The method according to claim 1, characterized in that: The step of selecting a preset number of candidate reference stations from at least one of the grids including the reference stations according to a preset random algorithm based on the probability information comprises: Taking the total number of reference stations included in each of the grids as a total sample, and based on the probability information, repeatedly selecting a preset number of candidate reference stations from at least one of the grids including the reference stations according to a preset random algorithm until the number of repetitions reaches a preset number threshold; The candidate reference station selected each time is stored in a pre-built reference station list.

5. The method according to claim 4, characterized in that The step of determining a preset number of candidate reference stations that meet a preset screening criterion as target reference stations comprises: Calculating a distribution index corresponding to a preset number of the candidate reference stations, wherein the distribution index is used to measure the uniform distribution degree of the preset number of the candidate reference stations; If the distribution index reaches a preset minimum threshold, determining that a preset number of the candidate reference stations meet the screening criteria; and, A preset number of the candidate reference stations are determined as the target reference stations.

6. The method according to claim 1, characterized in that The method further comprises: In response to a positioning service request, obtaining location information of a marine target based on the land-sea integrated coordinate frame control network; obtaining at least one preconfigured error correction model; Correcting the position information based on at least one of the error correction models; The error correction model includes at least one of the following models: an ionospheric multi-frequency combination elimination model, a tropospheric delay partition modeling, and a tidal error partition correction model.

7. The method according to claim 1, characterized in that The method further comprises: Analyzing the correlation between target reference stations included in the land-sea integrated coordinate frame control network; Selecting a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation; The common mode errors of a preset number of the related reference stations are calculated to correct the accuracy of the land-sea integrated coordinate frame control network based on the common mode errors.

8. The method according to claim 7, characterized in that The step of analyzing the correlation between target reference stations included in the land-sea integrated coordinate frame control network comprises: Calculating correlation coefficients between each of the target reference stations based on time series information of the target reference stations included in the land-sea integrated coordinate frame control network; The step of selecting a preset number of related reference stations from the target reference stations included in the land-sea integrated coordinate frame control network based on the correlation comprises: At least one of the target reference stations whose correlation coefficient is higher than a preset coefficient threshold is selected as a related reference station.

9. A device for constructing a land-sea integrated coordinate frame control network, characterized in that: The device comprises: An acquisition module, used to acquire distribution information of pre-established reference stations in a target area, wherein the target area includes a pre-divided land and sea area; A division module, used for dividing the target area into a preset number of grids based on the distribution information; A statistical module, used for counting the total number of reference stations contained in each of the grids, and for allocating probability information to the reference stations in each of the grids; wherein the probability information is used to characterize the probability that the reference station is determined as a station of the land-sea integrated coordinate frame control network; A selection module, configured to select a preset number of candidate reference stations from at least one of the grids including the reference station according to a preset random algorithm based on the probability information; The construction module is used to determine a preset number of the candidate reference stations that meet the preset screening criteria as target reference stations, so as to construct the land-sea integrated coordinate frame control network based on the target reference stations.

10. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in any one of claims 1 to 8 when executing the computer program.

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