CN118191890A - GNSS non-differential non-combination high-precision single point positioning method and system - Google Patents
GNSS non-differential non-combination high-precision single point positioning method and system Download PDFInfo
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Abstract
The invention provides a GNSS non-differential non-combination high-precision single point positioning method and system. The method comprises the following steps: error source compensation and correction are carried out on GNSS satellite navigation signals, and pseudo-range observed values after compensation and correction and carrier phase observed values after compensation and correction are obtained; establishing a GNSS non-differential non-combination precise single-point positioning observation model and a random model by using the compensated and corrected pseudo-range observation value and the compensated and corrected carrier phase observation value; according to the GNSS non-differential non-combination precise single-point positioning observation model and the random model, a floating solution of GNSS non-differential non-combination precise single-point positioning and a corresponding original frequency floating ambiguity thereof are obtained; and (3) carrying out ambiguity fixing on the floating ambiguity to obtain a fixed solution of GNSS non-differential non-combination precise single-point positioning.
Description
Technical Field
The present invention relates to GNSS positioning, and in particular to GNSS-based single point positioning.
Background
Precise single point positioning (Precise point positioning, PPP) is one of the research hotspots of GNSS navigation satellite precise positioning technology. The integer ambiguity fixing for carrier phase observations is a key point to achieving precise single point positioning and high precision applications. Because floating ambiguity of the carrier-phase observations absorbs uncalibrated hardware delays (Uncalibrated PHASE DELAYS, UPD) at the navigation satellite and receiver ends, the corresponding ambiguity cannot be fixed to an integer, limiting the navigation satellite precision single-point positioning application. For precision single-point positioning solution, there are currently a solution based on floating solution positioning and a solution based on fixed solution positioning. In general, a solution based on fixed solution positioning may be preferred over a solution based on floating solution positioning. In the whole-cycle ambiguity fixing (Ambiguity resolution, AR), a relatively common method is the LAMBDA algorithm, and when the whole-cycle ambiguity fixing is performed, the residual error of all candidate ambiguity combinations needs to be calculated, the Ratio (reliability test value Ratio) of the residual error of the suboptimal ambiguity combination and the residual error of the optimal ambiguity combination is considered to be true ambiguity if the Ratio is greater than a certain threshold. In general, the greater the Ratio value, the higher the reliability of the ambiguity solution. However, the Ratio value set when PPP performs integer ambiguity fixing is often an empirical value, and if the Ratio is set too low, the ambiguity is erroneously fixed, and if the Ratio is set too high, the integer ambiguity may not be fixed.
Disclosure of Invention
The present invention, in view of the above, proposes to alleviate or eliminate one or more of the disadvantages of the prior art and to provide at least one advantageous choice.
The invention provides a GNSS non-differential non-combination high-precision single point positioning method, which is characterized by comprising the following steps of: error source compensation and correction are carried out on GNSS satellite navigation signals, a pseudo-range observed value after compensation and correction and a carrier phase observed value after compensation and correction are obtained, the pseudo-range observed value after compensation and correction is the difference between the pseudo-range observed value after eliminating satellite end differential code deviation of the GNSS satellite navigation signals and a satellite distance initial value, the carrier phase observed value after compensation and correction is the difference between the carrier phase observed value of the GNSS satellite navigation signals and the satellite distance initial value, and a GNSS non-differential non-combination precise single-point positioning observed model and a random model are established by utilizing the pseudo-range observed value after compensation and correction and the carrier phase observed value after compensation and correction; according to the GNSS non-differential non-combination precise single-point positioning observation model and the random model, a floating solution of GNSS non-differential non-combination precise single-point positioning and a corresponding original frequency floating ambiguity thereof are obtained; and (3) carrying out ambiguity fixing on the floating ambiguity to obtain a fixed solution of GNSS non-differential non-combination precise single-point positioning.
According to one embodiment of the present invention, further comprising: obtaining a reliability statistics test amount Ratio value; and according to the reliability statistics test amount Ratio value, confirming the floating solution and the fixed solution to obtain a GNSS non-differential non-combination high-precision single point positioning result.
The invention also relates to a GNSS non-differential non-combination high-precision single point positioning system and a computer readable storage medium corresponding to the method.
According to some embodiments of the invention, a fixed solution may be better obtained. According to some embodiments of the present invention, the advantages of the floating solution and the fixed solution can be fully utilized, and the information of the floating solution can be fully utilized, so that the defect generated by simply solving the fixed solution can be overcome.
Drawings
The invention may be better understood with reference to the accompanying drawings. The drawings are merely illustrative and not drawn to scale and do not limit the scope of the invention.
FIG. 1 is a schematic diagram of a GNSS non-differential non-combined precise single point positioning method according to an embodiment of the invention;
FIG. 2 shows a schematic flow diagram of a stationary solution for obtaining a non-differential non-combined precise single point location in accordance with one embodiment of the invention;
FIG. 3 shows a schematic block diagram of a GNSS non-differential non-combined precision single point positioning system in accordance with an embodiment of the present invention.
Detailed Description
Specific embodiments of the invention will be described in further detail below with reference to the drawings, but are not to be construed as limiting the invention in any way. The components which are not shown in the drawings and which are not relevant to the operation of the embodiments of the invention but are not described in the specification, can be implemented by various techniques which are now known or later known, and are all within the scope of the invention. The specific embodiments of the present invention are not intended to be limiting, with the scope of the patent being defined by the claims. The features of the embodiments of the description should not be used to limit the scope of the claims.
The non-differential non-combination observation model is a common positioning model in the GNSS precise single-point positioning field, adopts an original pseudo-range and a phase observation equation, estimates ionosphere parameters, can be constrained by external ionosphere information to achieve the effect of accelerating convergence, and can be used for researching ionosphere modeling, inversion and the like. The observed quantity of the non-differential non-combination model is not combined and differentiated, so that ionosphere-free combination amplification residual model errors and observation noise are avoided, the model is high in expandability, and unified expression of the multi-frequency PPP model is facilitated.
The inventors of the present invention have found that positioning accuracy can be improved if an ambiguity fixing solution is performed for floating ambiguity of non-differential non-combined precision single-point positioning. In addition, the inventor has found that in known high-precision single point positioning solutions that seek a fixed solution, no information of the floating solution is used. The inventors of the present invention found that in many cases, although the accuracy of the floating solution may be lower than that of the fixed solution, if fully utilized, the problem in the fixed solution can be offset.
FIG. 1 is a schematic diagram of a GNSS non-differential non-combined precise single point positioning method according to an embodiment of the invention. As shown in fig. 1, according to one embodiment of the present invention, at step S10, error source compensation and correction are performed on GNSS satellite navigation signals, and a pseudo-range observed value after error source compensation and correction, and a carrier phase observed value after error source compensation and correction are obtained, where the pseudo-range observed value after error source compensation and correction is a difference between a pseudo-range observed value after eliminating a satellite-side differential code bias of the GNSS satellite navigation signals and a satellite-ground distance initial value, and the carrier phase observed value after error source compensation and correction is a difference between a carrier phase observed value of the GNSS satellite navigation signals and the satellite-ground distance initial value.
According to one embodiment, in high-precision single-point positioning based on single-system GPS, BDS (BDS-2 or BDS-3 or BDS-2+BDS-3), galileo, GLONASS, IRNSS, QZSS and the like or based on multi-system multi-frequency combination system (i.e. tight combination or loose combination of multi-mode multi-frequency) and the like of GNSS satellite navigation signals, firstly, error compensation and correction are carried out on a tropospheric delay dry component, antenna phase center deviation, phase winding, relativistic effect, tide and other GNSS positioning error sources, and a compensated pseudo-range observed value and a carrier phase observed value expressed as follows are obtained:
In the method, in the process of the invention, Respectively obtaining a pseudo-range observed value and a carrier phase observed value which are subjected to error compensation; superscript s is the PRN number of the GNSS satellite end, and C is the GNSS system; subscript r is the GNSS receiver end; subscript j is the frequency number; /(I)A wavelength corresponding to the designated frequency j; /(I)The geometrical distance between the GNSS satellite end s and the GNSS receiver end r; c is the speed of light in vacuum; dt s,C is the GNSS receiver clock difference and the GNSS satellite clock difference, respectively; /(I) A tropospheric delay wet mapping function related to satellite altitude; ZWD r is zenith direction troposphere delay wet component; /(I)An ionospheric delay amplification factor that is frequency dependent; /(I)Ionospheric delay corresponding to a first frequency f 1; /(I)The integer ambiguity corresponding to the carrier phase observation value; /(I)Pseudo-range hardware delays corresponding to the GNSS receiver end and the GNSS satellite end are respectively provided; Carrier phase hardware delays corresponding to the GNSS receiver end and the GNSS satellite end respectively; /(I) Noise is measured for pseudorange observations and carrier phase observations, respectively, that include residual errors that are not modeled.
Further, the pseudo-range observed value and the carrier phase observed value after error compensation are corrected by considering hardware delay, and the pseudo-range observed value and the carrier phase observed value after compensation and correction are obtained.
Since the pseudorange hardware delay is relatively stable, it is generally broken down into a frequency independent term and a frequency dependent term. The corresponding pseudo-range hardware delay for the GNSS receiver may be decomposed into:
Similarly, the pseudo-range hardware delay corresponding to the GNSS satellite end may be decomposed into:
Where m r、nr is the frequency independent term and the frequency dependent term of the pseudo-range hardware delay of the GNSS receiver, respectively, which can be considered to be absorbed by the GNSS receiver clock error and the ionospheric delay, respectively; m s、ns is a frequency independent term and a frequency dependent term of the pseudo-range hardware delay of the GNSS satellite end respectively, and m s can be generally considered to be absorbed by GNSS satellite clock difference, and n s can be corrected by a Differential Code Bias (DCB) parameter.
However, carrier phase hardware delays have significant time-varying characteristics, and generally decompose into a constant portion and a time-varying portion. The carrier phase hardware delay corresponding to the GNSS receiver may be decomposed into:
Similarly, the carrier phase hardware delay corresponding to the GNSS satellite end can be decomposed into:
In the method, in the process of the invention, The carrier phase hardware delay constant parts corresponding to the GNSS receiver end and the GNSS satellite end respectively can be considered to be absorbed by the integer ambiguity parameters due to the constant characteristics; /(I)The carrier phase hardware delay time-varying parts corresponding to the GNSS receiver side and the GNSS satellite side respectively can be generally decomposed into a frequency independent term and a frequency dependent term. The time-varying part corresponding to the carrier phase hardware delay of the GNSS receiver can be decomposed into:
similarly, the time-varying part corresponding to the carrier phase hardware delay of the GNSS satellite end can be decomposed into:
Wherein g r、kr is a frequency-independent term and a frequency-dependent term of the carrier phase hardware delay time-varying part of the GNSS receiver, which can be considered to be absorbed by the GNSS receiver clock difference and the ionosphere parameter respectively; g s、ks is the frequency independent term and the frequency dependent term of the carrier phase hardware delay time-varying part of the GNSS satellite end respectively, and it can be generally considered that g s is absorbed by the GNSS satellite clock difference, and k s is absorbed by the ionospheric delay parameter.
The following are true for formulas (3) to (6):
Wherein, The difference code deviation of the GNSS receiver end and the GNSS satellite end is respectively; Differential time-varying phase deviations of the GNSS receiver end and the GNSS satellite end are respectively obtained; subscript 1, j is the first frequency f 1 and the j-th frequencies f j;α1j and β 1j are ionospheric-free combined model coefficients; /(I) Corresponding pseudo-range hardware delay of the GNSS receiver end and the GNSS satellite end without ionosphere combination respectively; /(I) The carrier phase hardware delay time-varying parts are respectively corresponding to the GNSS receiver end and the GNSS satellite end without ionosphere combination.
Further, in step S20, a GNSS non-differential non-combination precise single point positioning observation model and a random model are established using the compensated and corrected pseudo-range observation value and the compensated and corrected carrier phase observation value.
Because the precise satellite clock error product is usually obtained based on the combination of double frequency ionosphere-free layers, the precise clock errorThe pseudo-range hardware delay and phase hardware delay time-varying part without ionosphere combination is included in the pseudo-range hardware delay and phase hardware delay time-varying part without ionosphere combination, namely:
if the following steps are made:
Linearizing the formulas (1) - (2), and finishing to obtain a GNSS non-difference non-combination precise single point positioning observation model in step S20:
In the method, in the process of the invention, The pseudo-range observed value and the initial value/>, of the satellite distance after correction, are compensated by the differential code deviation of the GNSS satellite endThe difference, namely the pseudo-range observed value after error source compensation correction; /(I)Is the initial value of the carrier phase observation value and the satellite distanceThe difference, namely the carrier phase observed value after error source compensation correction; /(I)The direction unit cosine from the GNSS satellite end to the GNSS receiver end is given; v X is the correction of the three-dimensional coordinates of the measuring station.
According to one embodiment, from equations (10) - (11), a satellite altitude angle weighting method may be used to build a corresponding random model as:
Wherein a and b are constants; e is the satellite altitude in radians. The observation model of the formulas (10) - (11) and the random model of the formula (12) can form a GNSS-based non-differential non-combination precise single point positioning model, namely, the non-differential non-combination precise single point positioning observation model and the random model are established.
Subsequently, in step S30, a non-differential non-combined floating solution (or called a GNSS non-differential non-combined precise single point positioning floating solution) of the precise single point positioning and a corresponding original frequency floating ambiguity are obtained according to the non-differential non-combined precise single point positioning observation model and the random model.
According to one embodiment, the parameters such as three-dimensional coordinate parameters of a measuring station, clock difference of a GNSS receiver, zenith direction troposphere delay wet component (ZWD), station star direction ionosphere bias delay, and original frequency floating ambiguity, which are related in the non-differential non-combination precise single point positioning observation model and the random model, are optimally estimated by using an Extended Kalman Filter (EKF), and the result is expressed as:
Wherein X 0 is the initial value of the three-dimensional coordinate parameter of the measuring station, and can be obtained by pseudo-range single-point positioning; v X is the correction of the three-dimensional coordinate parameters of the measuring station; v X+X0 is the three-dimensional coordinate parameter of the measuring station, and is called a non-differential non-combined precise single-point positioning floating solution. The variance-covariance matrix D X corresponding to each parameter, namely the three-dimensional coordinate parameter of the measuring station, the clock difference of the GNSS receiver, the zenith direction troposphere delay wet component (ZWD), the station star direction ionosphere bias delay, the original frequency floating ambiguity and the like is as follows:
Where d 2 is the variance-covariance matrix (diagonal element) of each parameter; d is the covariance matrix (off-diagonal element) between the parameters. Wherein, The variance-covariance matrix corresponding to the non-differential non-combined precise single-point positioning floating point solution for measuring station single-point positioning precision evaluation can be expressed as follows:
Wherein sigma 2 is a variance element (diagonal element) corresponding to the correction of the three-dimensional coordinate parameter of the measuring station (or the three-dimensional coordinate parameter of the measuring station); sigma is the covariance element (off-diagonal element) between the corrections of the coordinate parameters of the station (or the coordinate parameters of the station).
Next, in step S40, the floating ambiguity corresponding to the floating solution is fixed in ambiguity, so as to obtain a fixed solution of non-differential non-combined precise single point positioning. When the ambiguity is fixed, the residual error of all candidate ambiguity combinations needs to be calculated, the Ratio of the residual error of the suboptimal ambiguity combination to the residual error of the optimal ambiguity combination is determined, or when the integer value of the whole week unknown parameter is determined, the Ratio of the suboptimal unit weight variance to the minimum unit weight variance is generated, and for convenience of description, the Ratio is called a reliability check quantity Ratio value. According to one embodiment, in this step S40, a reliability check Ratio value is calculated simultaneously. The reliability check value Ratio may be obtained by various methods known in the art or known in the future, and will not be described in detail.
FIG. 2 shows a schematic flow diagram of a stationary solution for obtaining a non-differential non-combined precise single point location in accordance with one embodiment of the invention.
As shown in FIG. 2, first, in step S210, the GNSS non-differential non-combination 1 st frequency floating ambiguity and the j-th frequency floating ambiguity are utilized to obtain ionosphere-free combination floating ambiguity and its corresponding variance covariance matrix. According to one embodiment, the following will be describedOriginal frequency floating ambiguity sum/>The original frequency floating ambiguity is combined without an ionosphere to obtain the floating ambiguity without the ionosphere combination, which is as follows:
In the method, in the process of the invention, For ionosphere-free combined wavelength, it is assumed that the floating solution ambiguity parameters obtained from the GNSS non-differential non-combined precise single-point positioning observation model and the random model are:
In the method, in the process of the invention, And/>Floating ambiguity corresponding to the first frequency and the jth frequency of the multi-frequency satellite navigation signal respectively,
The variance covariance matrix corresponding to the ionosphere combination floating ambiguity or not is as follows:
In the method, in the process of the invention, A variance covariance matrix corresponding to the ionosphere-free combined floating ambiguity; d NN is the variance covariance matrix corresponding to the original frequency floating ambiguity. Wherein,
M＝[A1 B1]T (19)
In the method, in the process of the invention,
According to the followingOriginal frequency floating ambiguity sum/>The original frequency floating ambiguity, the obtained floating point wide lane ambiguity is:
In the method, in the process of the invention, The floating point wide lane ambiguity; /(I)The delay is the hardware delay of the wide lane at the GNSS receiver end, and is in units of weeks.
Then, as shown in fig. 2, in step S230, the inter-star single-difference ionospheric-free combined ambiguity and the inter-star single-difference floating-point widelane ambiguity are obtained using the ionospheric-free combined floating ambiguity and the floating-point widelane ambiguity.
According to one implementation mode, a satellite with the largest altitude angle is selected as a reference satellite, and the single-difference processing between satellites is carried out on the ionosphere-free combined floating ambiguity and the floating wide lane ambiguity which are formed by the original frequencies, so that the hardware delay of the GNSS receiver end wide lane is eliminated, and the single-difference ionosphere-free combined floating ambiguity between satellites and the single-difference floating wide lane ambiguity between satellites are formed. It should be appreciated that because inter-satellite single-difference ionospheric-free combined ambiguities are affected by residual errors, inter-satellite single-difference ionospheric-free combined floating ambiguity and inter-satellite single-difference floating-point widelane ambiguities may not have integer characteristics.
Next, in step S240, ambiguity fixing is performed on the inter-satellite single-difference floating-point widelane ambiguity, so as to obtain a fixed inter-satellite single-difference widelane ambiguity.
According to one embodiment, ambiguity is fixed on inter-satellite single-difference floating-point widelane ambiguities by a fixed criterion, a nearest rounding method, to obtain fixed inter-satellite single-difference widelane ambiguities (i.e., the inter-satellite single-difference widelane ambiguities have integer characteristics).
Then, in step S250, the inter-satellite single difference ionosphere-free combined floating ambiguity and the fixed inter-satellite single difference widelane ambiguity are used to obtain the inter-satellite single difference floating narrow elane ambiguity.
According to one embodiment, first, the inter-satellite single difference ionosphere-free combined floating ambiguity is resolved into corresponding widelane ambiguities and narrow elane ambiguities as follows:
In the method, in the process of the invention, Is a narrow lane wavelength; /(I)The corresponding narrow-lane ambiguity and wide-lane ambiguity are respectively.
Then, according to one embodiment, the inter-satellite single difference floating point narrow lane ambiguity is found as follows:
Wherein s 1 is a reference star and s 2 is a non-reference star; is a fixed inter-satellite single-difference widelane ambiguity. The variance-covariance matrix corresponding to the single-difference floating point narrow-lane ambiguity between the stars is as follows:
In the method, in the process of the invention, The variance-covariance matrix corresponding to the single difference ionosphere-free combined floating ambiguity between the stars.
Then, in step S260, the ambiguity fixing is performed on the inter-satellite single-difference floating-point narrow-lane ambiguity, so as to obtain a fixed inter-satellite single-difference narrow-lane ambiguity.
According to one embodiment, from equations (22) - (23), the fixed inter-satellite single-difference narrow-lane ambiguity can be determined using some algorithm (e.g., LAMBDA algorithm), while obtaining a reliability test Ratio value, and determining whether the confirmation of the fixed inter-satellite single-difference narrow-lane ambiguity is successful based on the Ratio value:
If the Ratio value is greater than or equal to a certain threshold (for example, 1.5-3.0, usually set to 2.0), in the LAMBDA algorithm operation process, judging that the fixed inter-satellite single-difference narrow-lane ambiguity is successful, and further obtaining the fixed inter-satellite single-difference narrow-lane ambiguity;
If the Ratio value is smaller than a certain threshold (for example, 1.5-3.0, usually set to 2.0), in the operation process of the LAMBDA algorithm, the fixed inter-satellite single-difference narrow-lane ambiguity is judged to be failed, and then the operation process of the fixed solution of the non-difference non-combination precise single-point positioning corresponding to the current epoch is terminated, and the operation process of the fixed solution of the non-difference non-combination precise single-point positioning corresponding to the next epoch is entered.
Subsequently, in step S270, a fixed inter-satellite single difference ionization-free combined ambiguity is obtained from the fixed inter-satellite single difference narrow-lane ambiguity and the fixed inter-satellite single difference wide-lane ambiguity.
According to one embodiment, a fixed inter-star single difference no ionization combined ambiguity is obtained from equation (22):
In the method, in the process of the invention, Is a narrow lane wavelength; /(I)The corresponding narrow lane ambiguity (i.e., the fixed inter-satellite single difference narrow lane ambiguity) and the wide lane ambiguity (i.e., the fixed inter-satellite single difference wide lane ambiguity) are respectively.
Finally, in step S280, a fixed solution of non-differential non-combined single point positioning is obtained according to the fixed inter-satellite single difference non-ionization combined ambiguity.
According to one embodiment, the fixed inter-satellite single difference ionization-free combined ambiguity is used as a constraint, and a floating solution of non-differential non-combined precise single point positioning is corrected to obtain a fixed solution of non-differential non-combined precise single point positioning.
Wherein X is a floating point solution of non-differential non-combined precise single point positioning; combining floating ambiguity matrixes for single difference ionosphere-free between satellites; /(I) Combining floating ambiguity matrixes for fixed inter-star single difference ionosphere-free combinations; d XX is a variance covariance matrix corresponding to a floating point solution of non-difference non-combination precise single point positioning; /(I)For X and/>Is a covariance matrix of (1); /(I)A variance covariance matrix corresponding to the single difference ionosphere-free combined floating ambiguity between the stars; accordingly, a new three-dimensional coordinate parameter of the measuring station is obtainedNamely, a non-differential non-combined precise single point positioning fixed solution and a variance-covariance matrix of the corresponding non-differential non-combined single point positioning fixed solution for measuring station single point positioning precision evaluation can be expressed as follows:
Wherein sigma 2 is a variance element (diagonal element) corresponding to the correction of the three-dimensional coordinate parameter of the measuring station (or the three-dimensional coordinate parameter of the measuring station); sigma is the covariance element (off-diagonal element) between the corrections of the coordinate parameters of the station (or the coordinate parameters of the station).
According to the method, in the step, through carrying out single difference between planets on the ionosphere-free combined floating point ambiguity and floating point wide lane ambiguity, after the integral characteristics of the two ambiguities are restored, factors such as combined wavelength, noise level, degree influenced by the ionosphere and the like are comprehensively considered, the single-difference floating point wide lane ambiguity between stars and the single-difference floating point narrow lane ambiguity between stars are sequentially and gradually fixed according to the order of easiness in use and difficulty, and finally, the non-difference non-combined original frequency ambiguity is fixed, and the ambiguity fixing rate and the positioning accuracy are improved.
Returning to fig. 1, finally, in step S50, the floating solutions and the fixed solutions are confirmed by using the Ratio value, so as to obtain a GNSS-based high-precision single-point positioning result.
If Ratio is more than or equal to 3.0, according to one embodiment, confirming the variance-covariance matrix of the non-differential non-combined single-point positioning fixed solution and the corresponding non-differential non-combined single-point positioning fixed solution for measuring station single-point positioning precision evaluation as a GNSS-based high-precision precise single-point positioning result;
If 3.0> ratio is greater than or equal to 2.0, according to one embodiment, performing weighting processing according to the non-differential non-combined single point positioning floating solution and the corresponding variance-covariance matrix, and according to the non-differential non-combined single point positioning fixed solution and the corresponding variance-covariance matrix by using a currently known method (for example, a Hermmett variance component estimation method, a minimum norm quadratic unbiased estimation method, an optimal invariant quadratic unbiased estimation method and the like) or a future known method, so as to realize a GNSS-based high-precision single point positioning result based on each floating solution and the fixed solution;
If 2.0> ratio is greater than or equal to 1.5, according to one embodiment, according to the non-differential non-combined single point positioning floating point solution and the fixed solution, a GNSS-based high-precision single point positioning result is confirmed as follows:
Where ω is a weight coefficient, determined as follows:
Wherein ω is a weight coefficient; η 1 =1.4 to 1.6, usually set to 1.5; η 2 =2.4 to 2.6, usually set to 2.5; v X The floating solution correction and the corresponding variance of the three-dimensional coordinate parameters of the measuring station are respectively obtained; /(I)A fixed solution correction for the three-dimensional coordinate parameters of the measuring station; /(I)A variance-covariance matrix of a solution is fixed for the three-dimensional coordinate parameters of the measuring station; x 0 is the initial coordinate of the measuring station, which is obtained by pseudo-range single-point positioning.
If 1.5 is greater than or equal to Ratio >1.0, according to one embodiment, the variance-covariance matrix of the non-differential non-combined single-point positioning floating solution and the corresponding non-differential non-combined single-point positioning floating solution for measuring station single-point positioning precision evaluation is confirmed to be a GNSS-based high-precision precise single-point positioning result.
FIG. 3 illustrates a schematic block diagram of a GNSS high precision single point positioning system in accordance with an embodiment of the present invention. As shown in FIG. 3, the GNSS non-differential non-combined high precision single point positioning system according to one embodiment includes an error source compensation correction unit 10, a model building unit 20, a floating solution and floating ambiguity acquisition unit 30, a fixed solution acquisition unit 40, and a positioning result confirmation unit 50.
The error source compensation and correction unit 10 performs error source compensation and correction on the GNSS satellite navigation signal to obtain a compensated and corrected pseudo-range observation value and a compensated and corrected carrier phase observation value, wherein the compensated and corrected pseudo-range observation value is the difference between the pseudo-range observation value after eliminating the satellite end differential code deviation of the GNSS satellite navigation signal and the satellite distance initial value, and the compensated and corrected carrier phase observation value is the difference between the carrier phase observation value of the GNSS satellite navigation signal and the satellite distance initial value.
The model building unit 20 builds a GNSS non-differential non-combined single point positioning observation model and a random model using the compensated pseudo-range observation value and the compensated carrier phase observation value.
The floating solution and floating ambiguity obtaining unit 30 obtains a floating solution of the GNSS non-differential non-combined single-point positioning and its corresponding original frequency floating ambiguity according to the GNSS non-differential non-combined single-point positioning observation model and the random model.
The fixed solution obtaining unit 40 performs ambiguity fixing on the floating ambiguity to obtain a fixed solution of GNSS non-differential non-combined single point positioning, and obtains a reliability statistics test amount Ratio value.
The positioning result confirming unit 50 confirms the floating solution and the fixed solution according to the reliability statistics test amount Ratio value, and obtains a GNSS non-differential non-combination high-precision single point positioning result.
According to one embodiment, the stationary solution acquisition unit 40 obtains a stationary solution of GNSS non-differential non-combined single point positioning as follows:
The GNSS non-differential non-combination 1 st frequency floating ambiguity and the j frequency floating ambiguity and the variance covariance matrix thereof are utilized to obtain ionosphere-free combination floating ambiguity and the variance covariance matrix thereof; obtaining floating point wide lane ambiguity by using the GNSS non-difference non-combination 1 st frequency floating point ambiguity and the j-th frequency floating point ambiguity; obtaining single-difference ionosphere-free combined floating ambiguity and single-difference floating wide lane ambiguity between stars by using the ionosphere-free combined floating ambiguity and the floating wide lane ambiguity; carrying out ambiguity fixing on the inter-satellite single-difference floating point wide lane ambiguity to obtain a fixed inter-satellite single-difference wide lane ambiguity; according to the single difference ionosphere-free combined floating ambiguity and the fixed single difference widelane ambiguity between the stars, obtaining single difference floating narrow elane ambiguity between the stars; carrying out ambiguity fixing on the inter-satellite single-difference floating point narrow-lane ambiguity to obtain a fixed inter-satellite single-difference narrow-lane ambiguity; obtaining fixed inter-satellite single-difference ionization-free combined ambiguity according to the fixed inter-satellite single-difference narrow-lane ambiguity and the fixed inter-satellite single-difference wide-lane ambiguity; and correcting the floating point solution of the non-differential non-combination precise single point positioning by taking the fixed inter-satellite single difference non-ionization combination ambiguity as constraint to obtain a fixed solution of the non-differential non-combination precise single point positioning.
The positioning result confirmation unit 50 may operate as follows.
According to one embodiment, when Ratio is greater than or equal to 3.0, confirming the variance-covariance matrix of the non-differential non-combined single-point positioning fixed solution and the corresponding non-differential non-combined single-point positioning fixed solution for measuring station single-point positioning precision evaluation as a GNSS-based high-precision precise single-point positioning result;
According to one embodiment, when 3.0 is greater than or equal to Ratio >2.0, the positioning result confirmation unit obtains a floating solution of GNSS non-differential non-combined single point positioning and a variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combined single point positioning according to the GNSS non-differential non-combined single point positioning observation model and the random model, weights the variance elements of the variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combined single point positioning and the variance elements of the variance-covariance matrix corresponding to the fixed solution by using a Hummett variance component estimation method,
According to one embodiment, when 2.0> ratio is greater than or equal to 1.5, according to one embodiment, the non-differential non-combined precise single point positioning floating solution and the fixed solution are used, and the high-precision single point positioning result based on GNSS is confirmed as follows:
Where ω is a weight coefficient, determined as follows:
where η 1 =1.4 to 1.6, usually set to 1.5; η 2 =2.4 to 2.6, usually set to 2.5; v X The floating solution correction and the corresponding variance of the three-dimensional coordinate parameters of the measuring station are respectively obtained; /(I)A fixed solution correction for the three-dimensional coordinate parameters of the measuring station; /(I)A variance-covariance matrix of a solution is fixed for the three-dimensional coordinate parameters of the measuring station; x 0 is the initial coordinate of the measuring station, which is obtained by pseudo-range single-point positioning.
According to one embodiment, when 1.5 is greater than or equal to Ratio >1.0, the variance-covariance matrix of the non-differential non-combined single-point positioning floating solution and the corresponding non-differential non-combined single-point positioning floating solution for measuring station single-point positioning precision evaluation is confirmed to be a GNSS-based high-precision precise single-point positioning result.
The foregoing description of the method may be applied to an understanding and application of the corresponding elements of the system of the present invention.
The numbering of the steps of the method of the present invention is for convenience of description only, and is not a specification or explanation of the order of execution thereof, and it should be understood by those skilled in the art that the order of the steps may be modified or some steps may be executed in parallel according to actual circumstances.
The units of the invention can be realized by hardware, or can be realized by software in combination with hardware, or can be realized by a processor executing software stored in a memory. The foregoing detailed description of the invention is merely further believed to be representative of the principles of the invention and is provided by those skilled in the art to practice the preferred aspects of the invention and not to limit the scope of the invention. Only the claims are used to determine the scope of the invention. Thus, combinations of features and steps in the foregoing detailed description are not necessary to practice the invention in the broadest scope and are instead taught merely to particularly detailed representative examples of the invention. Furthermore, the various features of the teachings set forth in the specification may be combined in a number of ways in order to obtain additional useful embodiments of the invention, however, such ways are not specifically enumerated.
Claims (10)
1. The GNSS non-differential non-combination high-precision single point positioning method is characterized by comprising the following steps of:
Error source compensation and correction are carried out on GNSS satellite navigation signals, so as to obtain a pseudo-range observed value after compensation and correction and a carrier phase observed value after compensation and correction, wherein the pseudo-range observed value after compensation and correction is the difference between the pseudo-range observed value after eliminating satellite end differential code deviation of the GNSS satellite navigation signals and the initial value of the satellite distance, and the carrier phase observed value after compensation and correction is the difference between the carrier phase observed value of the GNSS satellite navigation signals and the initial value of the satellite distance;
Establishing a GNSS non-differential non-combination precise single point positioning observation model and a random model by using the pseudo-range observation value after compensation and correction and the carrier phase observation value after compensation and correction;
According to the GNSS non-differential non-combination precise single-point positioning observation model and the random model, a floating solution of GNSS non-differential non-combination precise single-point positioning and a corresponding GNSS non-differential non-combination precise single-point positioning original frequency floating ambiguity thereof are obtained, wherein the GNSS non-differential non-combination precise single-point positioning original frequency floating ambiguity comprises a1 st frequency floating ambiguity and a j th frequency floating ambiguity; and
And (3) carrying out ambiguity fixing on the floating ambiguity to obtain a fixed solution of GNSS non-differential non-combination precise single-point positioning.
2. The method of claim 1, wherein the step of ambiguity fixing the floating ambiguity, obtaining a fix solution for GNSS non-differential non-combined precise single point positioning, comprises:
Obtaining ionosphere-free combined floating ambiguity and a variance covariance matrix thereof by using GNSS non-differential non-combination of the 1 st frequency floating ambiguity, the j-th frequency floating ambiguity and the variance covariance matrix corresponding to the two floating ambiguities;
obtaining floating point wide lane ambiguity by using the GNSS non-difference non-combination 1 st frequency floating point ambiguity and the j-th frequency floating point ambiguity;
Obtaining single-difference ionosphere-free combined floating ambiguity and single-difference floating wide lane ambiguity between stars by using the ionosphere-free combined floating ambiguity and the floating wide lane ambiguity;
Carrying out ambiguity fixing on the inter-satellite single-difference floating point wide lane ambiguity to obtain a fixed inter-satellite single-difference wide lane ambiguity;
Obtaining inter-satellite single difference floating point narrow lane ambiguity according to the inter-satellite single difference ionosphere-free combined floating point ambiguity, the variance covariance matrix and the fixed inter-satellite single difference wide lane ambiguity;
carrying out ambiguity fixing on the inter-satellite single-difference floating point narrow-lane ambiguity to obtain a fixed inter-satellite single-difference narrow-lane ambiguity;
Obtaining fixed inter-satellite single-difference ionization-free combined ambiguity according to the fixed inter-satellite single-difference narrow-lane ambiguity and the fixed inter-satellite single-difference wide-lane ambiguity; and
And correcting the floating point solution of the non-differential non-combination precise single point positioning by taking the fixed inter-satellite single difference non-ionization combination ambiguity as constraint to obtain a fixed solution of the non-differential non-combination precise single point positioning.
3. The method according to claim 1, wherein the method further comprises:
obtaining a reliability statistics test amount Ratio value; and
Confirming the floating solution and the fixed solution according to the reliability statistics test amount Ratio value to obtain a GNSS non-differential non-combination high-precision single point positioning result,
In the step of obtaining a GNSS non-differential non-combined high precision single point positioning result,
When the Ratio is more than or equal to 3.0 and is more than or equal to 2.0, a floating solution of GNSS non-differential non-combination precise single point positioning and a variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combination precise single point positioning are obtained according to the GNSS non-differential non-combination single point positioning observation model and the random model, and a variance element of the variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combination precise single point positioning and a variance element of the variance-covariance matrix corresponding to the fixed solution are subjected to weighting processing by using a Hummett variance component estimation method.
4. The method according to claim 1, wherein the method further comprises:
obtaining a reliability statistics test amount Ratio value; and
Confirming the floating solution and the fixed solution according to the reliability statistics test amount Ratio value to obtain a GNSS non-differential non-combination high-precision single point positioning result,
In the step of obtaining a GNSS non-differential non-combined high precision single point positioning result,
When the ratio of 2.0> is more than or equal to 1.5, according to the floating solution and the fixed solution of the non-differential non-combination precise single point positioning, the high-precision single point positioning result based on GNSS is confirmed as follows:
Where ω is a weight coefficient, determined as follows:
wherein eta 1＝1.4～1.6,η2＝2.4～2.6,VX and The floating solution correction and the corresponding variance of the three-dimensional coordinate parameters of the measuring station are respectively obtained; /(I)A fixed solution correction for the three-dimensional coordinate parameters of the measuring station; /(I)A variance-covariance matrix of a solution is fixed for the three-dimensional coordinate parameters of the measuring station; x 0 is the initial coordinate of the measuring station, which is obtained by pseudo-range single-point positioning.
5. The method of claim 1, wherein the GNSS non-differential non-combined precise single point positioning observation model is:
The random model is:
In the method, in the process of the invention, And/>The difference between the observed value and the calculated value of the pseudo-range and the carrier wave respectively; /(I)The direction unit cosine from the GNSS satellite end to the GNSS receiver end is given; v X is the three-dimensional coordinate correction of the measuring station; c is the speed of light; /(I)Clock skew for the receiver; A tropospheric delay wet mapping function related to satellite altitude; ZWD r is zenith direction troposphere delay wet component; For the ionospheric delay amplification factor in relation to frequency,/> Ionospheric delay corresponding to a first frequency f 1; The original ambiguity corresponding to the frequency j; /(I) The wavelength corresponding to the frequency j; /(I)Measuring noise for a pseudo-range observation value and a carrier phase observation value which respectively comprise residual errors which are not modeled, wherein a and b are constants; e is the satellite altitude in radians.
6. The method of claim 2, wherein ionosphere-free combined floating ambiguity and its corresponding variance-covariance matrix are obtained as follows: will beOriginal frequency floating ambiguity sum/>The original frequency floating ambiguity is combined without an ionosphere to obtain the floating ambiguity without the ionosphere combination, which is as follows:
In the method, in the process of the invention, For ionosphere-free combined wavelength, it is assumed that the floating solution ambiguity parameters obtained from the GNSS non-differential non-combined precise single-point positioning observation model and the random model are:
In the method, in the process of the invention, And/>Floating ambiguity corresponding to the first frequency and the jth frequency of the multi-frequency satellite navigation signal respectively,
The variance covariance matrix corresponding to the ionosphere combination floating ambiguity or not is as follows:
In the method, in the process of the invention, A variance covariance matrix corresponding to the ionosphere-free combined floating ambiguity; d NN is a variance covariance matrix corresponding to the original frequency floating ambiguity, where,
M＝[A1 B1]T (19)
In the method, in the process of the invention,
According to the followingOriginal frequency floating ambiguity sum/>The original frequency floating ambiguity, the obtained floating point wide lane ambiguity is:
In the method, in the process of the invention, The floating point wide lane ambiguity; /(I)The delay is the hardware delay of the wide lane at the GNSS receiver end, and is in units of weeks.
7. The method of claim 2, wherein the single-difference floating point narrow-lane ambiguity between stars is determined as follows:
Wherein s 1 is a reference star and s 2 is a non-reference star; the method is characterized by comprising the following steps of determining the single-difference wide lane ambiguity between satellites, wherein the variance-covariance matrix corresponding to the single-difference floating point narrow lane ambiguity between satellites is as follows:
In the method, in the process of the invention, For the variance-covariance matrix corresponding to the single difference ionosphere-free combined floating ambiguity between stars,
The fixed solution of non-difference non-combination precise single point positioning is obtained according to the fixed inter-satellite single difference non-ionization combination ambiguity as follows:
Correcting the floating solution of the non-differential non-combination precise single point positioning by taking the fixed inter-satellite single difference non-ionization combination ambiguity as constraint to obtain a fixed solution of the non-differential non-combination precise single point positioning:
Wherein X is a floating point solution of non-differential non-combined precise single point positioning; combining floating ambiguity matrixes for single difference ionosphere-free between satellites; /(I) Combining floating ambiguity matrixes for fixed inter-star single difference ionosphere-free combinations; d XX is a variance covariance matrix corresponding to a floating point solution of non-difference non-combination precise single point positioning; /(I)For X and/>Is a covariance matrix of (1); /(I)A variance covariance matrix corresponding to the single difference ionosphere-free combined floating ambiguity between the stars; accordingly, a new measuring station three-dimensional coordinate parameter/> isobtainedThe non-differential non-combined precise single-point positioning fixed solution is obtained by pseudo-range single-point positioning, wherein X 0 is the initial coordinate of a measuring station.
8. A GNSS non-differential non-combined precision single point positioning system, the system comprising:
The error source compensation correction unit is used for carrying out error source compensation and correction on the GNSS satellite navigation signals to obtain a pseudo-range observed value after compensation and correction and a carrier phase observed value after compensation and correction, wherein the pseudo-range observed value after compensation and correction is the difference between the pseudo-range observed value after eliminating the satellite end differential code deviation of the GNSS satellite navigation signals and the initial value of the satellite distance, and the carrier phase observed value after compensation and correction is the difference between the carrier phase observed value of the GNSS satellite navigation signals and the initial value of the satellite distance;
The model building unit is used for building a GNSS non-differential non-combination precise single-point positioning observation model and a random model by using the pseudo-range observation value after compensation and correction and the carrier phase observation value after compensation and correction;
The floating solution and floating ambiguity obtaining unit obtains a floating solution of GNSS non-differential non-combination precise single-point positioning and a corresponding original frequency floating ambiguity according to the GNSS non-differential non-combination precise single-point positioning observation model and the random model; and
And the fixed solution acquisition unit is used for carrying out ambiguity fixing on the floating ambiguity to obtain a fixed solution of GNSS non-differential non-combination precise single-point positioning.
9. The system of claim 8, wherein the stationary solution acquisition unit obtains a stationary solution for GNSS non-differential non-combined precise single point positioning as follows:
Obtaining ionosphere-free combined floating ambiguity and a variance covariance matrix thereof by using GNSS non-differential non-combination of the 1 st frequency floating ambiguity, the j-th frequency floating ambiguity and the variance covariance matrix corresponding to the two floating ambiguities;
obtaining floating point wide lane ambiguity by using the GNSS non-difference non-combination 1 st frequency floating point ambiguity and the j-th frequency floating point ambiguity;
Obtaining single-difference ionosphere-free combined floating ambiguity and single-difference floating wide lane ambiguity between stars by using the ionosphere-free combined floating ambiguity and the floating wide lane ambiguity;
Carrying out ambiguity fixing on the inter-satellite single-difference floating point wide lane ambiguity to obtain a fixed inter-satellite single-difference wide lane ambiguity;
Obtaining inter-satellite single difference floating point narrow lane ambiguity according to the inter-satellite single difference ionosphere-free combined floating point ambiguity, the variance covariance matrix and the fixed inter-satellite single difference wide lane ambiguity;
carrying out ambiguity fixing on the inter-satellite single-difference floating point narrow-lane ambiguity to obtain a fixed inter-satellite single-difference narrow-lane ambiguity;
Obtaining fixed inter-satellite single-difference ionization-free combined ambiguity according to the fixed inter-satellite single-difference narrow-lane ambiguity and the fixed inter-satellite single-difference wide-lane ambiguity; and
And correcting the floating point solution of the non-differential non-combination precise single point positioning by taking the fixed inter-satellite single difference non-ionization combination ambiguity as constraint to obtain a fixed solution of the non-differential non-combination precise single point positioning.
10. The system according to claim 8, wherein:
the fixed solution acquisition unit also acquires a reliability statistical test quantity Ratio value; and
The system also comprises a positioning result confirmation unit which confirms the floating solution and the fixed solution according to the reliability statistics test quantity Ratio value to obtain a GNSS non-difference non-combination high-precision single point positioning result,
When the Ratio is more than or equal to 3.0 and is more than or equal to 2.0, the positioning result confirming unit obtains a floating solution of GNSS non-differential non-combination precise single point positioning and a variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combination precise single point positioning according to the GNSS non-differential non-combination precise single point positioning observation model and the random model, carries out weight determination processing on the variance elements of the variance-covariance matrix corresponding to the floating solution of GNSS non-differential non-combination precise single point positioning and the variance elements of the variance-covariance matrix corresponding to the fixed solution by using a Hummett variance component estimation method,
When the ratio of 2.0> is more than or equal to 1.5, according to the floating solution and the fixed solution of the GNSS non-differential non-combination precise single point positioning, the high-precision single point positioning result based on the GNSS is confirmed as follows:
Where ω is a weight coefficient, determined as follows:
wherein eta 1＝1.4～1.6,η2＝2.4～2.6,VX and The floating solution correction and the corresponding variance of the three-dimensional coordinate parameters of the measuring station are respectively obtained; /(I)A fixed solution correction for the three-dimensional coordinate parameters of the measuring station; /(I)And (3) a variance-covariance matrix of a solution for the three-dimensional coordinate parameters of the measuring station, wherein X 0 is the initial coordinate of the measuring station and is obtained by pseudo-range single-point positioning.
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