CN118068676A - Real-time GNSS satellite clock error service method and system based on parameter decoupling - Google Patents
Real-time GNSS satellite clock error service method and system based on parameter decoupling Download PDFInfo
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Abstract
The invention discloses a real-time GNSS satellite clock difference service method and a system based on parameter decoupling, wherein the method comprises the steps of performing parameter resolving estimation by a filter to obtain an ambiguity and satellite clock difference estimated value according to reference station observation data flow and GNSS broadcast ephemeris data collected during real-time data processing, performing ambiguity parameter decoupling with the satellite clock difference parameter, calculating an ambiguity epoch-to-epoch variation value, deducting the ambiguity epoch-to-epoch variation value from the satellite clock difference value, and broadcasting a satellite clock difference product to a user in real time after the completion of the ambiguity and satellite clock difference. The invention solves the problem of the reduction of the real-time satellite clock error accuracy possibly caused by the coupling of the ambiguity parameter and the satellite clock error parameter, so as to realize the real-time GNSS satellite clock error service with higher accuracy.
Description
Technical Field
The invention belongs to the technical field of global satellite navigation systems (Global Navigation SATELLITE SYSTEM, GNSS), and particularly relates to a real-time GNSS satellite clock error service technical scheme based on parameter decoupling.
Background
In recent years, GNSS system construction and research are continuously developed, and GNSS technology has been widely applied to the fields of military, mapping, disaster prevention and reduction, electric power telecommunication, engineering construction, transportation and the like, and has become an indispensable technology for modern life.
Real-time kinematic (Real-TIME KINEMATIC, RTK) differential positioning and precision single point positioning (Precise Point Positioning, PPP) are representative of current GNSS high precision positioning techniques. Compared with the RTK technology, the PPP technology is not limited by the service distance of a reference station, and high-precision positioning is realized by using a precision satellite orbit clock error product; however, the traditional precise satellite orbit clock-difference product has different time delays ranging from a few hours to tens of days, and cannot realize the real-time application of the PPP technology. The real-time PPP technology is the development direction of PPP technology, and real-time GNSS orbit clock error service is needed for realizing the technology. The precision of the GNSS satellite forecast orbit product reaches the centimeter level, and the PPP technical requirement can be met; and GNSS satellite clock error products have strong volatility and great forecasting difficulty, and currently, a real-time estimation method is generally adopted to provide service.
Real-time GNSS satellite clock error estimation utilizes regional/global site real-time observation data flow to carry out whole network real-time calculation based on GNSS observation equation. The noise level of the GNSS carrier phase observations is significantly lower than that of the pseudo-range observations, so that the carrier phase observations have relatively higher weights in data processing; however, carrier phase observations are additionally affected by phase integer ambiguities, which are typically treated as random constants. The initial integer ambiguity is simply calculated from the pseudorange observations and the carrier phase observations to obtain a coarse value thereof, and then the coarse value is estimated by a solution. Because the carrier phase observations have higher weights, their impact on parameters such as satellite clock bias dominate in sophisticated data processing. Therefore, improving the ambiguity parameter processing strategy in the real-time satellite clock error estimation, thereby improving the real-time satellite clock error service accuracy is a problem which needs to be solved by the technicians in the field.
Disclosure of Invention
For a GNSS carrier phase observation equation, the ambiguity parameter is tightly coupled with the satellite clock error parameter; this means that the observation equation is still valid even if both types of parameters increase or decrease by a certain value (well below the noise level of the pseudorange observations). The invention discovers that in the real-time satellite clock error estimation, the coupling of the ambiguity parameter and the satellite clock error parameter can cause the slow change of a satellite clock error product, and the real-time satellite clock error service precision is reduced. Aiming at the problem, the invention provides a real-time GNSS satellite clock error service technical scheme based on parameter decoupling, and the two parameters are subjected to decoupling processing in real-time satellite clock error estimation data processing so as to realize higher-precision real-time GNSS satellite clock error service.
In order to achieve the above objective, the present invention provides a real-time GNSS satellite clock error service method based on parameter decoupling, which performs parameter calculation and estimation by using a filter to obtain an ambiguity and satellite clock error estimation value according to a reference station observation data stream and GNSS broadcast ephemeris data collected during real-time data processing, and then performs ambiguity parameter decoupling with the satellite clock error parameter, including calculating an ambiguity epoch-to-epoch variation value, then deducting the ambiguity epoch-to-epoch variation value from a satellite clock difference value, and then broadcasting a satellite clock error product to a user in real time after completion.
Moreover, the implementation process comprises the following steps,
Preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing;
collecting global or target area range reference station observation data streams and GNSS broadcast ephemeris data through network communication after the real-time data processing is started;
Performing parameter calculation and estimation by using a filter, wherein the parameters comprise an ambiguity parameter and a satellite clock error parameter;
After obtaining the estimated values of the ambiguity and the satellite clock difference, calculating the change value between the ambiguity epochs, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, thereby improving the real-time service precision;
And calculating the satellite broadcast ephemeris position and clock error based on the broadcast ephemeris, calculating the state domain correction of the forecast orbit and the subtracted satellite clock error value relative to the broadcast ephemeris position and clock error, and transmitting the SSR correction to a user in real time according to a protocol.
Furthermore, the ambiguity parameters are decoupled from the satellite clock error parameters, as follows,
Based on the following ionosphere-free combined observation model, the receiver clock error is consideredAnd satellite clock error parameter/>Tightly coupled, satellite clock error parameter/>, in carrier phase observation equationAnd ambiguity parameter/>The coupling is tight, and the coupling is tight,
In the method, in the process of the invention,、/>Receiver/>, respectivelyTracking satellite/>Ionosphere-free pseudoranges, phase combination observations; /(I)Is the geometric distance between the satellite and the receiver; /(I)、/>Receiver clock error, satellite clock error parameters; /(I)Is the station zenith troposphere delay,/>Is a troposphere projection function of zenith to inclined path; /(I)Is ionosphere free combined ambiguity; /(I)And/>Pseudo-range and phase observation noise, respectively;
For decoupling, after obtaining the ambiguity estimation, the level of variation between the ambiguity parameter epochs is calculated using the following equation:
In the method, in the process of the invention, Is different site to satellite/>Average change value of ambiguity parameter, wherein/>、/>Respectively represent the/>And/>Personal epoch,/>、/>Is the two epoch ambiguity estimate; /(I)Is the observation of satellite/>Site number,/>For the sequence number of the site,/>=1,2,…,/>；
Sequentially calculating the variation levels among different satellite ambiguity epochs, and then deducting the variation values from the estimated satellite clock difference parameters:
In the method, in the process of the invention, Is/>Satellites Zhong Chazhi,/>, estimated from individual epochsIs/>Satellite clock difference values after parameter decoupling processing is carried out on the individual epochs.
Moreover, the satellite forecast orbit product, the satellite DCB product, the reference station coordinate file, the antenna phase center correction file, and the table file are updated periodically in real-time data processing.
Moreover, the parameter calculation estimation is performed by using a filter, including filter time update, OMC calculation, normal equation establishment, filter measurement update and parameter value update.
Moreover, the filter time update is implemented using square root information filtering.
In another aspect, the present invention provides a real-time GNSS satellite clock error service system based on parameter decoupling, comprising the following modules,
The first module is used for preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing;
the second module is used for collecting the global range or target area range reference station observation data stream and GNSS broadcast ephemeris data through network communication after the real-time data processing is started;
The third module is used for carrying out parameter calculation and estimation by utilizing a filter, wherein the parameters comprise an ambiguity parameter and a satellite clock error parameter;
the fourth module is used for calculating a change value between ambiguity epochs after obtaining the ambiguity and the satellite clock difference estimated value, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, so that the real-time service precision is improved;
and a fifth module, configured to calculate a satellite broadcast ephemeris position and a satellite clock error based on the broadcast ephemeris, calculate a state domain correction of the forecast orbit and the subtracted satellite clock error value relative to the broadcast ephemeris position and the satellite clock error, and broadcast the SSR correction to the user in real time according to the protocol.
In another aspect, the present invention provides an electronic device comprising a memory and a processor, the processor and the memory completing communication with each other via a bus; the memory stores program instructions executable by the processor to invoke the program instructions to perform the real-time GNSS satellite clock differential service method based on parameter decoupling as described above.
In another aspect, the present invention provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a real-time GNSS satellite clock correction service method based on parameter decoupling as defined in any of the above.
The invention provides a real-time GNSS satellite clock error service technology based on ambiguity and clock error parameter decoupling, which solves the problem of real-time satellite clock error precision reduction possibly caused by the coupling of the ambiguity parameter and the satellite clock error parameter, so as to realize higher-precision real-time GNSS satellite clock error service.
Compared with the prior art, the invention has the characteristics that: after obtaining the estimated value of the ambiguity and the satellite clock difference, calculating the variation value between the ambiguity epochs, and deducting the variation value from the satellite clock difference value to realize the decoupling of the two parameters. The decoupling processing is carried out on the ambiguity parameter and the satellite clock error parameter in the novel mode, so that the real-time service precision can be improved.
The scheme of the invention is simple and convenient to implement, has strong practicability, solves the problems of low practicability and inconvenient practical application existing in the related technology, can improve user experience, and has important market value.
Drawings
FIG. 1 is a flow chart of a method according to an embodiment of the invention.
FIG. 2 is a schematic diagram of an ambiguity change sequence according to an embodiment of the present invention.
FIG. 3 is a schematic diagram showing the comparison of uncorrected and parameter-decoupled corrected satellite clock variations according to the method of the present invention.
Detailed Description
The technical scheme of the invention is specifically described below with reference to the accompanying drawings and examples. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, the real-time GNSS satellite clock error service method provided by the embodiment of the invention mainly includes the following processing steps:
Step 1, preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing, namely preparing various products and table files required by the data processing in advance during specific implementation, wherein the table file provides common model parameters, and the products and the table files can be updated periodically during the real-time data processing;
step 2, after the real-time data processing is started, the global/regional reference station observation data stream and GNSS broadcast ephemeris data are collected through network communication;
In practice, global or target regional scope observation data streams may be collected, i.e. global solutions are selected or solutions are only for partial regions. Step 3, performing parameter calculation and estimation by using a filter, wherein the parameter calculation and estimation mainly comprises filter time updating, calculation of subtracting a calculated value (Observation Minus Computation, OMC) from an observed value, normal equation establishment, filter measurement updating and parameter value updating; when in specific implementation, the step can be realized by referring to the prior art;
Step 4, calculating a change value between ambiguity epochs after obtaining the estimated value of the ambiguity and the satellite clock difference, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, thereby improving the real-time service accuracy;
The invention considers that the ionosphere-free combined (Ionosphere-free, IF) observation model is widely applied to satellite clock error estimation, and can be written as follows:
(1)
In the method, in the process of the invention, 、/>Receiver/>, respectivelyTracking satellite/>The ionosphere-free pseudo-range and phase combination observation values of the system are all in meters; /(I)The geometrical distance between the satellite and the receiver is corrected by considering the errors of the antenna phase center, earth rotation, tide and the like;、/> the clock difference parameters of the receiver and the satellite comprise pseudo-range hardware delay items of the receiver and the satellite respectively; /(I) Is the station zenith troposphere delay,/>Is a troposphere projection function of zenith to inclined path; /(I)The ionosphere-free combined ambiguity comprises a pseudo range of a receiver and a satellite end and a phase hardware delay term by taking meters as units; /(I)And/>Pseudo-range and phase observation noise, respectively.
From this, the embodiment of the invention further proposes that, as can be seen from equation (1), the receiver clock is poorAnd satellite clock error parameterTight coupling is typically solved by adding additional constraint equations; in addition, satellite clock error parameter/>, in carrier phase observation equationAnd ambiguity parameter/>Tightly coupled. For decoupling, after obtaining the ambiguity estimation, the level of variation between the ambiguity parameter epochs is calculated using the following equation:
(2)
In the method, in the process of the invention, Is different site to satellite/>Average change value of ambiguity parameter, wherein/>、/>Respectively represent the/>And/>Personal epoch,/>、/>Is the two epoch ambiguity estimate; /(I)Is the observation of satellite/>Site number,/>For the sequence number of the site,/>=1,2,…,/>。
Sequentially calculating the variation levels among different satellite ambiguity epochs, and then deducting the variation values from the estimated satellite clock difference parameters:
(3)
In the method, in the process of the invention, Is/>Satellites Zhong Chazhi,/>, estimated from individual epochsIs/>Satellite clock difference values after parameter decoupling processing is carried out on the individual epochs. The satellite clock error change caused by parameter coupling can be reduced based on the formula (3), so that the satellite clock error service precision, particularly the standard deviation (Standard Deviation, STD) precision, is improved.
Step 5, calculating the satellite broadcast ephemeris position and clock error based on the broadcast ephemeris, calculating the forecast orbit and the satellite Zhong Chazhi obtained in step 4And (3) broadcasting SSR corrections to users in real time according to a protocol relative to the broadcast ephemeris position and state field (STATE SPACE reproduction, SSR) corrections of clock errors.
In particular, the method according to the technical solution of the present invention may be implemented by those skilled in the art using computer software technology to implement an automatic operation flow, and a system apparatus for implementing the method, such as a computer readable storage medium storing a corresponding computer program according to the technical solution of the present invention, and a computer device including the operation of the corresponding computer program, should also fall within the protection scope of the present invention.
In particular, the real-time GNSS satellite clock error service method provided by the embodiment of the invention is preferably realized by adopting the following specific flow,
1) Preparing satellite forecast orbit products, satellite DCB products, reference station coordinate files and antenna phase center correction files. The products can be downloaded from an International GNSS service (International GNSS SERVICE, IGS) data center, and different products can be obtained through corresponding precise data processing; starting a product and table file real-time downloading process to realize periodic updating of the product and the table file;
2) Reading the various products and the table files in the step 1), and preprocessing and storing the read data;
3) Collecting site real-time observation data streams and broadcast ephemeris, and decoding and storing the real-time data streams according to NTRIP protocol;
4) Calculating satellite positions through the forecast orbit products, calculating geometrical distances between the satellites and the stations based on the satellite positions and the station positions, and correcting errors such as antenna phase centers, earth rotation, tides and the like; simultaneously determining satellites Zhong Chazhi, wherein the satellites are obtained by calculation initially through broadcast ephemeris, and the subsequent epoch adopts satellite clock difference estimated values; the calculation implementation of the step can be realized by adopting the prior art, and the invention is not repeated;
5) Single point location solutions (Single Point Positioning, SPP) are performed for different sites, an initial receiver Zhong Chazhi is calculated, and an initial ambiguity parameter value is calculated; detecting and marking the ambiguity cycle slip; removing sites with failure SPP calculation; the calculation implementation of the step can be realized by adopting the prior art, and the invention is not repeated;
6) The filter time update is carried out, and the method mainly comprises three steps of process noise introduction, new parameter insertion and old parameter elimination;
in particular implementations, square root information filtering may be employed. The implementation scheme of the preferred proposal provided by the embodiment of the invention is as follows:
In GNSS data processing, the state information of the jth epoch and the linearized observation equation can be expressed as follows:
(4)
In the method, in the process of the invention, For a priori information matrix,/>Is an observation matrix,/>Is a parameter vector to be estimated,/>Is an a priori observation vector that is a priori,Is the observation vector.
Unknowns can be determined based on time-varying propertiesThe method is divided into the following two parts:
(5)
In the method, in the process of the invention, Representing dynamic parameters,/>The time-invariant parameter is represented, and the superscript T is the matrix transposed symbol. Dynamic parameters typically employ a first order markov process, and the variation between epochs can be expressed as follows:
(6)
In the method, in the process of the invention, Represents the/>Dynamic parameters of individual epoch,/>Represents the/>Dynamic parameters of individual epoch,/>Representing a state transition matrix,/>Is process noise,/>The following conditions are satisfied:
(7)
In the middle of Represent the mean value/>Representing variance,/>Is a symmetrical positive definite matrix which can be decomposed into，/>The upper triangular matrix after decomposition is represented, the upper mark-1 represents inversion, and the upper mark T is a matrix transposition symbol; when two epochs/>、/>Satisfy the condition/>Time, cronecker function/>. In the specific implementation, the variance values of different noises are all provided with corresponding empirical models, and the invention is not repeated.
By means ofThe process noise variance in equation (6) may be unitized:
(8)
the comprehensive parameter prior information can be obtained:
(9)
In the method, in the process of the invention, Representing dynamic parameters (th /)Personal epoch information matrix,/>Representation of time invariant parameter No. >Personal epoch information matrix,/>The representation is the/>A single epoch observation vector.
QR decomposition the full-order matrix can be uniquely decomposed into an orthogonal matrix and an upper triangular matrix, and QR decomposition is performed on the left matrix in equation (9):
(10)
In the method, in the process of the invention, Is an orthogonal matrix obtained by QR decomposition,/>、/>、/>、/>、/>Is a sub-matrix of the upper triangular matrix obtained by QR decomposition, wherein/>Comprises the/>Dynamic parameter information of each epoch,/>、/>Comprises the first step ofDynamic parameter information of each epoch,/>、/>Time-invariant parameter information is included. Using orthogonal matrix propertiesThat is, the inverse matrix of the orthogonal matrix is the transposed matrix thereof, and the left and right sides of the equation (9) are multiplied by/>, respectivelyThe following formula can be obtained:
(11)
In the method, in the process of the invention, Representing epoch/>, after time updateObservation information of/>Representing epoch/>, after time updateIs a priori observed information of (1);
after the time is updated, the parameters can be deleted And the information matrix reduces the number of parameters and improves the resolving efficiency.
Assume the current parameter vector in the filterAnd information matrix/>The following are provided:
(12)
In the method, in the process of the invention, 、/>、/>Is a parameter vector/>To be estimated. /(I)Is associated with parameter/>Related information,/>、Is associated with parameter/>Related information,/>、/>、/>Is associated with parameter/>Related information.
If a parameter is needed to be addedAt/>And/>Between, the post-change parameter vector/>And information matrix/>The following are provided:
(13)
In the method, in the process of the invention, Representing new insertion parameter prior information;
If it is required to eliminate The parameters can be firstly adjusted to the first position with the corresponding state information in sequence, and the information matrix is subjected to QR decomposition, and the process is as follows:
(14)
In the method, in the process of the invention, 、/>、/>、/>、/>、/>Is a new information matrix value after QR decomposition processing. Direct elimination/>The post-parameters and corresponding information matrix are expressed as follows:
(15)
7) Calculating OMC values based on observations, satellite site geometry distances, satellite clock differences, satellite DCB values, ambiguity values, and other error correction values; the calculation implementation of the step can be realized by adopting the prior art, and the invention is not repeated;
8) Establishing a normal equation by using the OMC value, detecting the rough difference based on the OMC value, and eliminating an observation equation with overlarge rough difference; the calculation implementation of the step can be realized by adopting the prior art, and the invention is not repeated;
9) Performing filter measurement and updating to obtain a parameter correction value;
in specific implementation, the square root information filtering measurement update may be obtained by QR-decomposing equation (4):
(16)
Can then be utilized Unknown parameters are calculated.
In the method, in the process of the invention,Is the post-solution residual vector.
10 Parameter updating is carried out based on the parameter value and the parameter correction value obtained in the step 9), and a final parameter estimated value is obtained;
11 Sequentially calculating the change level of ambiguity parameters of each satellite to different sites based on the formula (2);
12 Based on the formula (3), subtracting the ambiguity parameter epoch change value from the satellite clock difference parameter; the implementation of steps 4) to 10) is a preferred implementation proposal of step 3 provided by the embodiment of the invention, the technical improvement of the invention mainly comprises steps 11) and 12), and the specific implementation is shown in the specific description of the step 4;
13 Calculating a broadcast satellite position and broadcast satellite Zhong Chazhi based on the broadcast ephemeris; calculating a precise satellite position based on the forecast orbit product, and obtaining a precise satellite clock difference based on the estimated satellite clock difference; the precise satellite position and the precise clock error are subjected to difference making to obtain a state domain correction value; converting the satellite position correction value into an orbit radial direction, a tangential direction and a normal direction; the step is performed based on the result obtained in the step 12), and specific calculation implementation can be realized by adopting the prior art, and the invention is not repeated;
14 The satellite position and the satellite clock correction value are broadcast according to the protocol. In practice, the international maritime radio technical commission (Radio Technical Commission for MARITIME SERVICES, RTCM) standard protocol is typically employed.
The real-time satellite clock error estimation is carried out based on the parameter decoupling method provided by the invention, so that satellite clock error change caused by ambiguity parameter change can be effectively improved, and the service accuracy of satellite clock error products, in particular standard deviation (STD) estimation indexes, can be improved. Fig. 2 shows a sequence of change between ambiguity epochs of two satellites G10 and G24 calculated by equation (2) when the simulated real-time satellite clock bias estimation is performed on 1 month 1 year 2024, and the abscissa is time (in hours) and the ordinate is ambiguity value (in ns), so that the change of the ambiguity parameter is obvious. FIG. 3 shows the clock error sequences of two satellites G10 and G24 corrected and uncorrected by the parameter decoupling method according to the invention, the abscissa is time (in hours), the ordinate is satellite Zhong Chazhi (in ns), when the satellite clock error sequences are not corrected by the parameter decoupling method, the satellite clock error sequences are basically consistent with the ambiguity change sequences, after the satellite clock error sequences are processed by the method according to the invention, the changes of the satellite clock error parameters influenced by the ambiguity parameter changes are corrected, the stability is obviously improved, the STD precision values of the satellite clock error products of the two methods are marked at the same time in the upper left corner of FIG. 3, and after the satellite clock error precision is obviously improved.
In particular, the method according to the technical solution of the present invention may be implemented by those skilled in the art using computer software technology to implement an automatic operation flow, and a system apparatus for implementing the method, such as a computer readable storage medium storing a corresponding computer program according to the technical solution of the present invention, and a computer device including the operation of the corresponding computer program, should also fall within the protection scope of the present invention.
In another possible embodiment, the present invention provides a real-time GNSS satellite clock error service system based on parameter decoupling, including:
The first module is used for preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing;
the second module is used for collecting the global range or target area range reference station observation data stream and GNSS broadcast ephemeris data through network communication after the real-time data processing is started;
The third module is used for carrying out parameter calculation and estimation by utilizing a filter, wherein the parameters comprise an ambiguity parameter and a satellite clock error parameter;
the fourth module is used for calculating a change value between ambiguity epochs after obtaining the ambiguity and the satellite clock difference estimated value, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, so that the real-time service precision is improved;
and a fifth module, configured to calculate a satellite broadcast ephemeris position and a satellite clock error based on the broadcast ephemeris, calculate a state domain correction of the forecast orbit and the subtracted satellite clock error value relative to the broadcast ephemeris position and the satellite clock error, and broadcast the SSR correction to the user in real time according to the protocol.
The specific implementation process of each module in the system is the same as that of the above method embodiment, and will not be repeated here.
In another possible embodiment, the present invention further provides a computer device, where the device may implement super-resolution reconstruction of the remote sensing image, and may be implemented by software and/or hardware. The apparatus includes: a memory, a processor, and a computer program stored on the memory and executable on the processor; when the processor executes the computer program, the steps of the real-time GNSS satellite clock error service method based on parameter decoupling are realized.
In particular, the Processor may be a central processing unit (Central Processing Unit, CPU), or other general purpose Processor, digital signal Processor (DIGITAL SIGNAL Processor, DSP), application Specific Integrated Circuit (ASIC), field-Programmable gate array (Field-Programmable GATE ARRAY, FPGA) or other Programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof.
In another possible embodiment, the present invention further provides a computer readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the real-time GNSS satellite clock error service method based on parameter decoupling.
The memory, as a non-transitory computer readable storage medium, may be used to store a non-transitory software program, a non-transitory computer executable program, and a module, such as a program or an instruction corresponding to the real-time GNSS satellite clock error service method based on parameter decoupling in the above embodiments.
The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, at least one application program required for a function; the data storage area may store data created by the processor, etc.
In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device.
In some aspects, the memory optionally includes memory remotely located relative to the processor, the remote memory being connectable to the processor through a network.
Optionally, the network includes, but is not limited to, the Internet, an Intranet, a local area network, a mobile communications network, and combinations thereof.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The specific examples described herein are offered by way of illustration only. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.
Claims (9)
1. A real-time GNSS satellite clock error service method based on parameter decoupling is characterized in that: according to reference station observation data flow and GNSS broadcast ephemeris data collected during real-time data processing, a filter is utilized to carry out parameter calculation and estimation to obtain an estimated value of ambiguity and satellite clock difference, then the ambiguity parameter and the satellite clock difference parameter are decoupled, the method comprises the steps of calculating a change value between ambiguity epochs, deducting the change value between the ambiguity epochs from a satellite clock difference value, and broadcasting a satellite clock difference product to a user in real time after the completion.
2. The real-time GNSS satellite clock skew service method based on parameter decoupling according to claim 1, wherein: the implementation process comprises the following steps of,
Preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing;
collecting global or target area range reference station observation data streams and GNSS broadcast ephemeris data through network communication after the real-time data processing is started;
Performing parameter calculation and estimation by using a filter, wherein the parameters comprise an ambiguity parameter and a satellite clock error parameter;
After obtaining the estimated values of the ambiguity and the satellite clock difference, calculating the change value between the ambiguity epochs, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, thereby improving the real-time service precision;
And calculating the satellite broadcast ephemeris position and clock error based on the broadcast ephemeris, calculating the state domain correction of the forecast orbit and the subtracted satellite clock error value relative to the broadcast ephemeris position and clock error, and transmitting the SSR correction to a user in real time according to a protocol.
3. The real-time GNSS satellite clock skew service method based on parameter decoupling according to claim 1, wherein: the ambiguity parameters are decoupled from the satellite clock error parameters, as follows,
Based on the following ionosphere-free combined observation model, the receiver clock error is consideredAnd satellite clock error parameter/>Tightly coupled, satellite clock error parameter/>, in carrier phase observation equationAnd ambiguity parameter/>The coupling is tight, and the coupling is tight,
In the method, in the process of the invention,、/>Receiver/>, respectivelyTracking satellite/>Ionosphere-free pseudoranges, phase combination observations; /(I)Is the geometric distance between the satellite and the receiver; /(I)、/>Receiver clock error, satellite clock error parameters; /(I)Is the station zenith troposphere delay,/>Is a troposphere projection function of zenith to inclined path; /(I)Is ionosphere free combined ambiguity; /(I)And/>Pseudo-range and phase observation noise, respectively;
For decoupling, after obtaining the ambiguity estimation, the level of variation between the ambiguity parameter epochs is calculated using the following equation:
In the method, in the process of the invention, Is different site to satellite/>Average change value of ambiguity parameter, wherein/>、/>Respectively represent the/>And/>Personal epoch,/>、/>Is the two epoch ambiguity estimate; /(I)Is the observation of satellite/>Site number,/>For the sequence number of the site,/>=1,2,…,/>；
Sequentially calculating the variation levels among different satellite ambiguity epochs, and then deducting the variation values from the estimated satellite clock difference parameters:
In the method, in the process of the invention, Is/>Satellites Zhong Chazhi,/>, estimated from individual epochsIs/>Satellite clock difference values after parameter decoupling processing is carried out on the individual epochs.
4. The real-time GNSS satellite clock skew service method based on parameter decoupling according to claim 1, wherein: the satellite forecast orbit product, satellite DCB product, reference station coordinate file, antenna phase center correction file and table file are updated periodically in real-time data processing.
5. The real-time GNSS satellite clock skew service method based on parameter decoupling according to claim 1, wherein: the method comprises the steps of utilizing a filter to carry out parameter calculation estimation, including filter time update, OMC calculation, french equation establishment, filter measurement update and parameter value update.
6. The method for real-time GNSS satellite clock correction service based on parameter decoupling according to claim 5, wherein: the filter time update is implemented using square root information filtering.
7. A real-time GNSS satellite clock error service system based on parameter decoupling is characterized by comprising the following modules,
The first module is used for preparing a satellite forecast orbit product, a satellite DCB product, a reference station coordinate file, an antenna phase center correction file and a table file in advance before real-time data processing;
the second module is used for collecting the global range or target area range reference station observation data stream and GNSS broadcast ephemeris data through network communication after the real-time data processing is started;
The third module is used for carrying out parameter calculation and estimation by utilizing a filter, wherein the parameters comprise an ambiguity parameter and a satellite clock error parameter;
the fourth module is used for calculating a change value between ambiguity epochs after obtaining the ambiguity and the satellite clock difference estimated value, and deducting the change value from the satellite clock difference value to realize decoupling of two types of parameters, so that the real-time service precision is improved;
and a fifth module, configured to calculate a satellite broadcast ephemeris position and a satellite clock error based on the broadcast ephemeris, calculate a state domain correction of the forecast orbit and the subtracted satellite clock error value relative to the broadcast ephemeris position and the satellite clock error, and broadcast the SSR correction to the user in real time according to the protocol.
8. An electronic device, characterized in that: the system comprises a memory and a processor, wherein the processor and the memory complete communication with each other through a bus; the memory stores program instructions executable by the processor, the processor invoking the program instructions capable of performing the parameter decoupling-based real-time GNSS satellite clock correction service method of any of claims 1 to 6.
9. A non-transitory computer readable storage medium having a computer program stored thereon, characterized by: the computer program, when executed by a processor, implements a real-time GNSS satellite clock correction service method based on parameter decoupling as claimed in any of the claims 1 to 6.
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