Method, device, equipment and computer storage medium for fixing base frequency ambiguity

Abstract

The disclosed embodiments provide a method, apparatus, device and computer storage medium for fixing baseband ambiguity. The method uses the initial value of wide lane ambiguity of observation data as a parameter to be estimated, and performs loose constraint filtering and tight constraint filtering and ambiguity domain search on the baseband ambiguity through wide lane observation equations and ionosphere-free combined equations, and finally obtains baseband ambiguity with high accuracy. The method is suitable for RTK positioning solution of medium and long baselines, and is also suitable for solution of short baselines, and does not require any changes, has a wide range of application, and has good solution effect.

Description

Technical Field

[0001] The present invention relates to the field of satellite positioning technology, and more particularly to a method, device, equipment and computer storage medium for fixing baseband ambiguity. Background Art

[0002] Based on double-difference GNSS relative positioning, after double-difference, the ionospheric error, tropospheric error, satellite clock error, receiver clock error, satellite ephemeris error, etc. in the short baseline can be fully weakened or completely eliminated. However, as the baseline length increases, the errors gradually increase and the spatial correlation weakens, especially the ionospheric error. Even after double-difference, the residual error is still large; when the baseline length exceeds 30km, it is difficult for the non-combined double-difference observation value to correctly fix the ambiguity, resulting in the inability to achieve high-precision RTK (Real-Time Kinematic) positioning effect. Summary of the invention

[0003] The embodiments of the present disclosure provide a method, apparatus, device and computer storage medium for fixing base frequency ambiguity, which can correctly fix the ambiguity and facilitate obtaining a high-precision positioning effect.

[0004] In a first aspect, an embodiment of the present disclosure provides a method for fixing a base frequency ambiguity, the method comprising:

[0005] Based on the carrier observation data of the reference station and the mobile station, the initial value of the wide lane ambiguity is calculated;

[0006] The baseband ambiguity initial value is filtered through the first joint observation equation, and the floating point solution of the first baseband ambiguity obtained after filtering is converted into a wide lane ambiguity filter value; the first joint observation equation includes an ionosphere-free combined observation equation and a wide lane ambiguity loose constraint equation, wherein the wide lane ambiguity loose constraint equation is constrained by the wide lane ambiguity initial value;

[0007] Perform ambiguity domain search on the wide lane ambiguity filter value to obtain fixed wide lane ambiguity;

[0008] The first baseband ambiguity is filtered again through the second joint observation equation to obtain a floating point solution of the second baseband ambiguity; the second joint observation equation includes an ionosphere-free combined observation equation and a wide lane ambiguity tight constraint equation, wherein the wide lane ambiguity tight constraint equation is constrained by a fixed wide lane ambiguity;

[0009] An ambiguity domain search is performed on the floating-point solution of the second baseband ambiguity to obtain a fixed solution of the baseband ambiguity of the carrier observation data.

[0010] In some embodiments, the initial value of the wide lane ambiguity is calculated based on the carrier observation data of the reference station and the mobile station, specifically including:

[0011] According to the dual-frequency carrier observation data of the reference station and the mobile station, the double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange and used as the initial value of the wide-lane ambiguity.

[0012] In some embodiments, the initial value of the wide lane ambiguity is calculated based on the carrier observation data of the reference station and the mobile station, specifically including:

[0013] According to the triple-frequency carrier observation data between reference stations, two sets of ultra-wide lane ambiguities are obtained by smoothing pseudoranges and rounding.

[0014] The two sets of ultra-wide lane ambiguities are combined to form the initial value of wide lane ambiguity.

[0015] In some embodiments, the initial value of the wide lane ambiguity is calculated based on the carrier observation data of the reference station and the mobile station, specifically including:

[0016] When the carrier observation data only include dual-frequency observation data, the double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange according to the dual-frequency carrier observation data of the reference station and the mobile station as the initial value of the wide-lane ambiguity;

[0017] When the carrier observation data includes triple-frequency observation data, two sets of ultra-wide lane ambiguities are obtained by smoothing and rounding the pseudoranges according to the triple-frequency carrier observation data between reference stations, and the two sets of ultra-wide lane ambiguities are combined to form the initial value of the wide lane ambiguity.

[0018] In some embodiments, after calculating the initial value of the wide lane ambiguity according to the carrier observation data of the reference station and the mobile station, and before filtering the initial value of the baseband ambiguity through the first joint observation equation and converting the floating point solution of the first baseband ambiguity obtained after filtering into the wide lane ambiguity filtered value, the method further includes:

[0019] The initial values ​​of wide lane ambiguity are extracted one by one, and the least squares solution is performed to obtain the corresponding multiple position data;

[0020] Outlier detection is performed according to the position data, and the corresponding wide lane ambiguity initial value of the position outlier is deleted to obtain the remaining wide lane ambiguity initial value after outlier detection;

[0021] The loosely constrained wide lane ambiguity equation is constrained by the initial value of the residual wide lane ambiguity.

[0022] In some embodiments, filtering the initial value of the baseband ambiguity through the first joint observation equation, and converting the floating-point solution of the first baseband ambiguity obtained after filtering into a wide-lane ambiguity filtering value specifically includes:

[0023] The first joint observation equation is composed of the following ionosphere-free combined observation equation (1) and the wide-lane ambiguity loose constraint equation (2):

[0024]

[0025]

[0026] Among them, φ1 and φ2 are the observed values ​​of carrier L1 frequency point and carrier L2 frequency point respectively. is the carrier phase observation value after ionospheric-free combination; f1 and f2 are the frequencies of carrier L1 frequency point and carrier L2 frequency point respectively; are the double-difference carrier phase observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; i, j represent the reference station respectively, N1, N2 represent the initial value of the fundamental frequency ambiguity of the observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively, △ represents the single difference between stations; N mw is the initial value of wide lane ambiguity.

[0027] In some embodiments, filtering the first baseband ambiguity again through the second joint observation equation to obtain a floating-point solution value of the second baseband ambiguity includes:

[0028] The second joint observation equation is composed of the following ionosphere-free combined observation equation (1) and the wide-lane ambiguity tight constraint equation (3):

[0029]

[0030]

[0031] is a fixed wide-lane ambiguity.

[0032] In a second aspect, an embodiment of the present disclosure provides a device for fixing a base frequency ambiguity, the device comprising:

[0033] The first calculation module is used to calculate the initial value of the wide lane ambiguity according to the carrier observation data of the reference station and the mobile station;

[0034] The first filtering module is used to filter the initial value of the baseband ambiguity through the first joint observation equation, and convert the floating-point solution of the first baseband ambiguity obtained after filtering into a wide-lane ambiguity filter value; The first joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity loose constraint equation, wherein the wide-lane ambiguity loose constraint equation is constrained by the initial value of the wide-lane ambiguity;

[0035] The first search module is used to perform ambiguity domain search on the wide lane ambiguity filter value to obtain a fixed wide lane ambiguity;

[0036] A second filtering module is used to filter the first baseband ambiguity again through a second joint observation equation to obtain a floating-point solution of the second baseband ambiguity; the second joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity tight constraint equation, wherein the wide-lane ambiguity tight constraint equation is constrained by a fixed wide-lane ambiguity;

[0037] The second search module is used to perform an ambiguity domain search on the floating-point solution of the second baseband ambiguity to obtain a baseband ambiguity fixed solution of the carrier observation data.

[0038] In a third aspect, an embodiment of the present disclosure provides a device for fixing base frequency ambiguity, the device comprising: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement a method for fixing base frequency ambiguity as described in any of the above embodiments.

[0039] In a fourth aspect, an embodiment of the present disclosure provides a computer storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, a method for fixing baseband ambiguity as in any of the above embodiments is implemented.

[0040] The positioning method, device, equipment and computer storage medium with fixed baseband ambiguity of the disclosed embodiments use the initial value of wide lane ambiguity of observation data as the parameter to be estimated, and perform loose constraint filtering and tight constraint filtering and ambiguity domain search on the baseband ambiguity through wide lane observation equation and ionosphere-free combination equation, so as to finally obtain the baseband ambiguity with high accuracy. The method is suitable for RTK positioning solution of medium and long baselines, and is also suitable for solution of short baselines, and does not require any changes, has a wide range of application, and has good solution effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solution of the embodiment of the present disclosure, the following is a brief introduction to the drawings required for use in the embodiment of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] Figure 1 It is a flowchart of a method for fixing base frequency ambiguity provided by an embodiment of the present disclosure;

[0043] Figure 2 It is a flowchart of a method for fixing base frequency ambiguity provided by a specific embodiment of the present disclosure;

[0044] Figure 3 yes Figure 1 A flowchart of an example of step S101 is shown in FIG.

[0045] Figure 4 yes Figure 2 A flowchart of a specific example of the method for fixing the base frequency ambiguity shown;

[0046] Figure 5 It is a structural schematic diagram of a device for fixing base frequency ambiguity provided by an embodiment of the present disclosure;

[0047] Figure 6 yes Figure 5 A schematic diagram of a structure of a specific example of a device for fixing base frequency ambiguity shown;

[0048] Figure 7 It is a structural diagram of a device with fixed baseband ambiguity provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0049] The features and exemplary embodiments of various aspects of the present disclosure will be described in detail below. In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present disclosure, rather than to limit the present disclosure. For those skilled in the art, the present disclosure can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present disclosure by illustrating examples of the present disclosure.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0051] In order to solve the problem that ambiguity is difficult to fix correctly in RTK positioning in long baseline, the methods commonly used in traditional technology mainly include three categories: (1) The non-combined observations and the combined ionosphere-free observations are filtered together, and the wide lane ambiguity and carrier L1 ambiguity are estimated as parameters to be estimated, and in the non-combined observations, the ionospheric parameters are used as parameters to be estimated. (2) The ionospheric error is estimated as a parameter to be estimated through the non-combined mode. At this time, the carrier L1 or L2 ambiguity is still directly estimated as a parameter to be estimated. (3) The three-frequency or multi-frequency ambiguity fixing technology fixes the long baseline ambiguity, and fixes the ultra-wide lane and wide lane ambiguities step by step, and finally fixes the L1 or L2 ambiguity. However, in methods (1) and (2), since each satellite sets an ionospheric parameter as a parameter to be estimated, plus the carrier L1 or L2 ambiguity parameter, there are too many parameters to be estimated in the observation equation, and the calculation speed is slow. In addition, this method requires the prior value of the ionospheric delay error and its process noise, which is not easy to accurately give, but is very critical, and its accuracy directly affects the correctness of the L1 or L2 ambiguity fixation. Method (3) requires triple-frequency observations, but there are currently few satellites with triple-frequency observations in GPS, and this method cannot be used when the receiver only supports dual-frequency observations.

[0052] In order to solve the problems in the prior art, the embodiments of the present disclosure provide a method, an apparatus, a device and a computer storage medium for fixing baseband ambiguity.

[0053] The following first introduces the method for fixing the base frequency ambiguity provided by the embodiment of the present disclosure.

[0054] Figure 1 FIG. 2 is a flow chart showing a method for fixing base frequency ambiguity provided by an embodiment of the present disclosure. Figure 1 As shown, the method may include the following steps:

[0055] S101. Calculate the initial value of wide lane ambiguity based on the carrier observation data of the reference station and the mobile station;

[0056] S102. The baseband ambiguity initial value is filtered through the first joint observation equation, and the floating-point solution of the first baseband ambiguity obtained after filtering is converted into a wide-lane ambiguity filtered value; the first joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity loose constraint equation, wherein the wide-lane ambiguity loose constraint equation is constrained by the wide-lane ambiguity initial value;

[0057] S103. Perform ambiguity domain search on the wide lane ambiguity filter value to obtain a fixed wide lane ambiguity;

[0058] S104. The first baseband ambiguity is filtered again through a second joint observation equation to obtain a floating-point solution of the second baseband ambiguity; the second joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity tight constraint equation, wherein the wide-lane ambiguity tight constraint equation is constrained by a fixed wide-lane ambiguity;

[0059] S105. Perform an ambiguity domain search on the floating-point solution of the second baseband ambiguity to obtain a fixed solution of the baseband ambiguity of the carrier observation data.

[0060] In this embodiment, the original baseband ambiguity is used as the parameter to be estimated, the wide lane ambiguity initial value is used, the ionosphere-free combined observation equation is combined with loose constraint filtering, and the fixed wide lane ambiguity is obtained through ambiguity domain search. The constraint filtering is tightened to obtain a more accurate floating point solution and baseband ambiguity floating point value, which can be applied not only to the calculation of medium and long baseline ambiguity, but also to the calculation of short baseline ambiguity.

[0061] Figure 2 The flowchart of the method for fixing the baseband ambiguity in a specific embodiment of the present disclosure is shown. In this embodiment, when performing step S101., the initial value of the wide lane ambiguity can be obtained by different methods according to the properties of the observed data. Specifically, step S101. may include:

[0062] When the carrier observation data only include dual-frequency observation data, the double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange according to the dual-frequency carrier observation data of the reference station and the mobile station as the initial value of the wide-lane ambiguity;

[0063] When the carrier observation data includes triple-frequency observation data, two sets of ultra-wide lane ambiguities are obtained by smoothing and rounding the pseudoranges according to the triple-frequency carrier observation data between reference stations, and the two sets of ultra-wide lane ambiguities are combined to form the initial value of the wide lane ambiguity.

[0064] Exemplarily, for dual-frequency carrier observation data, step S101. Calculating the initial value of wide lane ambiguity according to the carrier observation data of the reference station and the mobile station may specifically include:

[0065] According to the dual-frequency carrier observation data of the reference station and the mobile station, the double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange and used as the initial value of the wide-lane ambiguity.

[0066] In this example, by smoothing pseudoranges over multiple epochs, the double-difference MW wide-lane ambiguity can be obtained according to the following equations (1.1) and (1.2):

[0067]

[0068]

[0069] In formulas (1.1) and (1.2), N mw is the double-difference wide-lane MW ambiguity calculated at the current epoch t, ​​i.e., the initial value of the wide-lane ambiguity; represents the double difference operator, i.e., the double difference of the observation value or the combined observation value between stations (i.e., between the reference station and the mobile station) and between satellites, φ1 and φ2 are the observation values ​​of the carrier L1 frequency point and the carrier L2 frequency point, respectively, the same below; then are the double-difference carrier phase observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; f1 and f2 are the frequencies of carrier L1 frequency point and carrier L2 frequency point respectively; λ1 and λ2 are the wavelengths of carrier L1 frequency point and carrier L2 frequency point respectively, and P1 and P2 are the corresponding pseudo-range observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; is the smoothed MW wide-lane ambiguity of the current epoch t, ​​n is a positive integer greater than 1, indicating the smoothing coefficient, and the value of n can be set according to experience, such as 300.

[0070] In other examples, the method of obtaining the initial widelane ambiguity value of dual-frequency carrier observation data can also adopt the parameter to be estimated method, that is, the initial widelane ambiguity value is estimated as the parameter to be estimated; or the direct rounding method can be adopted, that is, the initial widelane ambiguity value is obtained by direct evidence through the single-epoch widelane pseudorange observation value combined with the widelane wavelength.

[0071] Figure 3 FIG. 1 is a flow chart showing a specific example of step S101. Figure 3 As shown, in this embodiment, exemplarily, for triple-frequency carrier observation data, step S101. Calculating the initial value of wide lane ambiguity according to the carrier observation data of the reference station and the mobile station may specifically include:

[0072] S301. According to the three-frequency carrier observation data between the reference stations, two sets of ultra-wide lane ambiguities are obtained by smoothing the pseudorange and rounding;

[0073] S302. Combine the two sets of ultra-wide lane ambiguities to form initial values ​​of wide lane ambiguities.

[0074] In this example, when it is determined from the observation data that there is triple-frequency carrier observation data (ie, triple-frequency carrier observation values, the same below), step S301 is performed. Two sets of ultra-wide lane observation values ​​are formed according to the triple-frequency carrier observation values, and the corresponding ultra-wide lane ambiguity is obtained directly by rounding the smoothed pseudorange. The triple-frequency carrier observation value can be expressed as follows (1.3):

[0075]

[0076] Among them, i, j, k are all integer coefficients, φ1, φ2, φ3 are the carrier observation values ​​in meters corresponding to the three frequency points, and f1, f2, f3 are the frequencies corresponding to the three frequency points.

[0077] The ambiguity of the triple-frequency carrier observation value (also known as the combined observation value, the same below) can be expressed as:

[0078] N (i,j,k) =i·N1+j·N2+k·N3 (1.4)

[0079] Among them, N1, N2, and N3 are the original observation ambiguities corresponding to the three frequency points (that is, the initial values ​​of the base frequency ambiguities).

[0080] The combined observation frequency can be expressed as:

[0081] f (i,j,k) =i·f1+j·f2+k·f3 (1.5)

[0082] The wavelength of the combined observation value can be expressed as:

[0083] λ (i,j,k) =c / f (i,j,k) (1.6)

[0084] Where c is the speed of light.

[0085] For different systems, the integer coefficients i, j, k should take different values, which can be empirical values. Appropriate integer coefficients are taken to obtain a combined observation value with a wavelength that is long enough and is most conducive to ambiguity resolution.

[0086] In this example, by smoothing the pseudorange and rounding it, the three-frequency pseudorange combined observation value in meters can be expressed as follows:

[0087]

[0088] In formula (1.7), P1, P2, and P3 are the pseudo-range observation values ​​corresponding to the three frequency points in the three-frequency carrier observation data, and || represents the absolute value. Therefore, the ultra-wide lane double difference ambiguity can be expressed as:

[0089]

[0090] In formula (1.8), represents the double difference operator, i.e., the double difference of the observation value or the combined observation value between stations and satellites, h represents the combination coefficient, [] represents rounding, so the ultra-wide lane ambiguity N t ewl(i,j,k) It is already an integer, and because the wavelength of the combined observation value is long, this value can basically be guaranteed to be 100% correct.

[0091] By smoothing the pseudorange and rounding, two sets of ultra-wide lane ambiguities are obtained, and the two sets of ultra-wide lane ambiguities are combined to form a wide lane ambiguity, that is, as the above-mentioned wide lane ambiguity initial value, the accuracy of this value will be higher than the accuracy of the smoothed MW wide lane ambiguity, and this value can replace the MW wide lane ambiguity. Because only some satellites have three-frequency observations at this time, only a small part of the MW ambiguity will be replaced to obtain the final wide lane ambiguity initial value.

[0092] Exemplarily, the calculation formula of the initial value of wide lane ambiguity can be expressed as:

[0093] N wl(i,j,k) =m·N 1 ewl(i,j,k) +n·N 2 ewl(i,j,k) (1.9)

[0094] Where N 1 ewl(i,j,k) , N 2 ewl(i,j,k) These are two sets of ultra-wide lane ambiguities obtained by two combination coefficients of ultra-wide lanes. For example, for GPS, the two sets of ultra-wide lane ambiguities (i, j, k) can be selected as (0, -1, 1) and (1, -6, 5) respectively, and m and n can be selected as (-5, 1).

[0095] In this example, when the wavelengths of the two selected sets of ultra-wide lanes are long enough, the rounding error can be ignored by directly rounding, and the possibility of ambiguity error is small. Then, after the two sets of ultra-wide lane ambiguities are converted into wide lane ambiguities through linear combination, the wide lane ambiguity has a higher accuracy.

[0096] In a specific embodiment, after calculating the initial value of the wide lane ambiguity based on the carrier observation data of the reference station and the mobile station, and before filtering the initial value of the baseband ambiguity through the first joint observation equation, and converting the floating-point solution of the first baseband ambiguity obtained after filtering into a wide lane ambiguity filtered value, the method for fixing the baseband ambiguity may also include: S106. Eliminating erroneous initial values ​​of the wide lane ambiguity.

[0097] For example, Figure 4 FIG. 4 shows a flow chart of step S106 in an example. Figure 4 As shown, step S106 may specifically include:

[0098] S401. Extract the initial values ​​of the wide lane ambiguity one by one, perform least squares solution, and obtain corresponding multiple position data;

[0099] S402, performing outlier detection according to the position data, deleting the corresponding wide lane ambiguity initial values ​​of the position outliers, and obtaining the remaining wide lane ambiguity initial values ​​after the outlier detection.

[0100] In this example, assuming that there are m wide lane ambiguity initial values, one wide lane ambiguity initial value is eliminated one by one, and the least squares solution is performed to finally obtain m position data results. The obtained m position data results are subjected to outlier detection, and the wide lane ambiguity initial values ​​corresponding to the obvious outliers are determined to be wrong values. These wrong values ​​are eliminated to obtain the remaining wide lane ambiguity initial values, which are used for subsequent loose constraint processing.

[0101] In step S106 of this embodiment, in other examples, a least squares solution may be performed using a fixed initial wide lane ambiguity value to eliminate initial wide lane ambiguity values ​​whose priori and posterior residuals are obviously outliers.

[0102] In this embodiment, after obtaining the accurate initial value of wide lane ambiguity, step S102 can be performed. The initial value of baseband ambiguity is filtered through the first joint observation equation, and the floating point solution of the first baseband ambiguity obtained after filtering is converted into the wide lane ambiguity filter value. In this step, the first joint observation equation includes the ionosphere-free combined observation equation and the wide lane ambiguity loose constraint equation, wherein the wide lane ambiguity loose constraint equation is constrained by the initial value of wide lane ambiguity; if step S106 is performed before step S103, the wide lane ambiguity loose constraint equation is constrained by the above-mentioned residual initial value of wide lane ambiguity.

[0103] Since the ionospheric error is the most critical factor affecting the solution of medium and long baselines, and the receiver clock error, satellite clock error, ionospheric error, etc. are basically greatly weakened or completely eliminated after the inter-station and inter-satellite double differences, only the influence of ionospheric error is considered in the equations listed here.

[0104] Ionospheric errors have a dispersion effect. By using this characteristic, dual-frequency observations can be combined to form new observations that are independent of the ionosphere, called ionospheric-free combined observations. The ionospheric-free combined observations eliminate the influence of the ionosphere, but the ambiguity of the combined observations no longer has an integer characteristic. Therefore, when using ionospheric-free combined observations to fix ambiguities, it is necessary to first convert the ionospheric-free observation ambiguities into a combination of wide-lane ambiguities and baseband ambiguities. After the wide-lane ambiguities are fixed, the fixation of the ionospheric-free observation ambiguities can be converted to the fixation of the baseband ambiguities.

[0105] In this embodiment, after obtaining a basically accurate initial value of the wide lane ambiguity through step S101, filtering is performed through the ionosphere-free combined observation equation and the wide lane ambiguity loose constraint equation, and the parameters to be estimated are only set to the position and the baseband ambiguity of the carrier L1 frequency point and the carrier L2 frequency point observation value. The parameters to be estimated are consistent with the parameters to be estimated in the short baseline solution.

[0106] Considering only the ionospheric error, the original observation equations of carrier L1 and carrier L2 in meters can be expressed as:

[0107]

[0108] In formula (2.1), ρ is the satellite-to-ground distance containing three-dimensional position information, (x, y, z), (x i ,y i ,z i ) are the receiver position of the parameter to be estimated and the satellite position of the known parameter respectively.

[0109] In formula (2.1), φ1 and φ2 are the observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively, f1 and f2 are the frequencies of carrier L1 frequency point and carrier L2 frequency point respectively; λ1 and λ2 are the wavelengths of carrier L1 frequency point and carrier L2 frequency point respectively, N1 and N2 represent the initial values ​​of the fundamental frequency ambiguity of the observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; c is the speed of light; A represents the same ionospheric delay term for different signals on the same propagation path.

[0110] Based on formula (2.1), the double-difference ionosphere-free combined observation equation after eliminating the ionosphere can be expressed as:

[0111]

[0112] In formula (2.2), is the carrier phase observation value after ionospheric-free combination; is the double difference operator, which means the double difference between stations and satellites. They are the double-difference carrier phase observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively.

[0113] When there are only ionospheric-free combined observations, there is rank deficiency when solving the initial baseband ambiguity values ​​N1 and N2, so it is necessary to add wide lane ambiguity constraint equations for the initial baseband ambiguity values ​​N1 and N2.

[0114] For example, the added wide lane ambiguity loose constraint equation can be expressed as:

[0115]

[0116] In formula (2.3), N mwis the initial value of the wide lane ambiguity; i, j represent the two satellites for inter-satellite difference, △ represents the inter-station single difference, That is, the inter-station single-difference ambiguity of the carrier L1 observation value to the i-satellite, That is, the inter-station single-difference ambiguity of the carrier L2 observation value to the i-satellite, That is, the inter-station single-difference ambiguity of the carrier L1 observation value to the j satellite, That is, the inter-station single-difference ambiguity of the carrier L2 observation value to the j satellite.

[0117] Therefore, the first joint observation equation is formed by the following ionosphere-free combined observation equation (2.2) and the wide-lane ambiguity loose constraint equation (2.3):

[0118]

[0119]

[0120] When the loosely constrained filtering is performed on the initial value of the baseband ambiguity through the first joint observation equation composed of the ionosphere-free observation equation and the wide-lane ambiguity loose constraint equation, the parameters to be estimated are the position (x, y, z) and the baseband station single-difference floating-point ambiguity of each satellite for each frequency point of the carrier, that is, △N1 and △N2.

[0121] After the baseband ambiguity initial value is loosely constrained, a floating point solution of the first baseband ambiguity is obtained; converting the floating point solution of the first baseband ambiguity into a wide lane ambiguity filter value may specifically include:

[0122] Convert the floating point solution of the baseband single-difference ambiguity △N1 and △N2 between carriers L1 and L2 into the double-difference wide-lane ambiguity N wl The conversion method is:

[0123]

[0124] In formula (2.4), the D matrix represents the conversion of the single-difference ambiguity between stations into the double-difference ambiguity matrix, and the A matrix represents the conversion of the double-difference ambiguity into the wide-lane ambiguity matrix. Specifically, it can be expressed as:

[0125]

[0126]

[0127] Then the variance covariance matrix P of the carrier L1 and L2 single difference ambiguity △N , converted to the variance-covariance matrix of the L1-L2 double-difference wide-lane ambiguity. The conversion formula is:

[0128] P wl =(A·D)·P△N ·(A·D) T (2.7)

[0129] In formula (2.7), () T Indicates the transposition of a matrix, and “·” indicates matrix multiplication.

[0130] The variance-covariance matrix of the double-difference wide-lane ambiguity obtained by formula (2.7) contains the wide-lane ambiguity filter value converted from the floating-point solution of the first baseband ambiguity.

[0131] In this embodiment, through step S103, a fuzziness domain search is performed on the obtained wide lane fuzziness filter value to obtain a fixed wide lane fuzziness.

[0132] For example, the wide lane ambiguity N can be fixed by lambda search. wl Since the wide lane ambiguity accuracy of lambda search is much higher than that of pseudorange smoothed wide lane ambiguity, the fixed wide lane ambiguity N obtained by search is used. wl The MW ambiguity N obtained by replacing the pseudorange smoothing mw .

[0133] Get a fixed wide lane ambiguity N with high accuracy wl After that, step S104 can be performed. The first baseband ambiguity is filtered again through the second joint observation equation to obtain a floating point solution of the second baseband ambiguity. The second joint observation equation includes an ionosphere-free combined observation equation and a wide lane ambiguity tight constraint equation, wherein the wide lane ambiguity tight constraint equation is constrained by a fixed wide lane ambiguity; and the calculation accuracy of the wide lane ambiguity tight constraint equation is higher than the calculation accuracy of the wide lane ambiguity loose constraint equation.

[0134] In step S104, the second joint observation equation may be composed of the following ionosphere-free combined observation equation (3.1) and the wide-lane ambiguity tight constraint equation (3.2):

[0135]

[0136]

[0137] is the fixed wide lane ambiguity. as well as The value is obtained after being constrained by formula (2.3), which is also the first base frequency ambiguity.

[0138] The second joint equation treats the fundamental frequency ambiguity constraint in the same way as the first joint equation, except that the constraint value is different. wlThe accuracy is higher than the initial value N of the wide lane ambiguity mw , fixed wide lane ambiguity N wl Replace the pseudo MW ambiguity N mw After that, when the tight constraint filter is added, the calculation accuracy of the wide lane ambiguity tight constraint equation is higher than the calculation accuracy of the wide lane ambiguity loose constraint equation. In other words, both constraints refer to the given wide lane constraint equation accuracy, and the difference is the relative size of the given accuracy; the accuracy of the tight constraint should be higher than the accuracy of the loose constraint. For example, when the wide lane constraint equation is loosely constrained, the accuracy range given is 0.01 to 0.001 m, and when the tight constraint is used, the accuracy range given can be 0.001 to 0.0005.

[0139] In this embodiment, through step S105, an ambiguity domain search is performed on the floating-point solution of the second baseband ambiguity to obtain a baseband ambiguity fixed solution of the carrier observation data.

[0140] For example, in step S105, the baseband ambiguity of carrier L1 and L2 frequency points can be fixed by lambda search. After step S104, relatively accurate floating point solution coordinates, baseband ambiguity N1, N2, and their corresponding variance covariance matrix P are obtained. △N At this time, the base frequency ambiguities N1 and N2 are directly fixed through labmda search, with a high fixing rate and a low probability of fixing errors. When the ambiguities are fixed, the floating point solution can be converted into a fixed solution.

[0141] The baseband ambiguity fixing method provided in this embodiment is based on the conversion of the original single-difference ambiguity into the wide-lane ambiguity method. It is simple and clear, and avoids the complex transformation caused by the wide-lane ambiguity as a parameter to be estimated. It can be applied to RTK positioning solution of medium and long baselines. Since the parameters to be estimated are consistent, it is also applicable to the solution of short baselines without any changes, and the effect is good.

[0142] Figure 5 The schematic diagram of the structure of a device for fixing baseband ambiguity provided by an embodiment of the present disclosure is shown as follows: Figure 5 The device shown includes:

[0143] The first calculation module 501 is used to calculate the initial value of the wide lane ambiguity according to the carrier observation data of the reference station and the mobile station;

[0144] The first filtering module 502 is used to filter the baseband ambiguity initial value through the first joint observation equation, and convert the floating-point solution of the first baseband ambiguity obtained after filtering into a wide-lane ambiguity filter value; the first joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity loose constraint equation, wherein the wide-lane ambiguity loose constraint equation is constrained by the wide-lane ambiguity initial value;

[0145] The first search module 503 is used to perform ambiguity domain search on the wide lane ambiguity filter value to obtain a fixed wide lane ambiguity;

[0146] The second filtering module 504 is configured to filter the first baseband ambiguity again through a second joint observation equation to obtain a floating point solution of the second baseband ambiguity; the second joint observation equation includes an ionosphere-free combined observation equation and a wide lane ambiguity tight constraint equation, wherein the wide lane ambiguity tight constraint equation is constrained by a fixed wide lane ambiguity;

[0147] The second search module 505 is used to perform an ambiguity domain search on the floating-point solution of the second baseband ambiguity to obtain a baseband ambiguity fixed solution for the carrier observation data.

[0148] Exemplarily, the first computing module 501 may perform the above Figure 1 In step S101 shown in FIG. 1 , the first filtering module 502 may perform the above Figure 1 In step S102 shown in FIG. 1 , the first search module 503 may perform the above Figure 1 In step S103 shown in FIG. 1 , the second filtering module 504 may perform the above Figure 1 In step S104 shown in FIG. 1 , the second search module 505 may perform the above Figure 1 Step S105 shown in FIG.

[0149] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and can achieve its corresponding technical effects. For the sake of concise description, they will not be repeated here.

[0150] In one embodiment, the apparatus may further include:

[0151] The error elimination module 601 is used to eliminate the erroneous initial value of the wide lane ambiguity. That is, the error elimination module 601 can perform the above Figure 3 Steps S401 and S402 shown in FIG.

[0152] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and can achieve its corresponding technical effects. For the sake of concise description, they will not be repeated here.

[0153] Figure 7 A hardware structure diagram of a device with fixed base frequency ambiguity provided by an embodiment of the present disclosure is shown.

[0154] The device for fixing the base frequency ambiguity may include a processor 701 and a memory 702 storing computer program instructions.

[0155] Specifically, the processor 701 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present disclosure.

[0156] The memory 702 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 702 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In one example, the memory 702 may include a removable or non-removable (or fixed) medium, or the memory 702 is a non-volatile solid-state memory. The memory 702 may be inside or outside the integrated gateway disaster recovery device.

[0157] The memory 702 may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Thus, in general, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0158] The processor 701 reads and executes the computer program instructions stored in the memory 702 to implement Figure 1 The method / steps S101 to S105 in the embodiment shown in the figure are achieved Figure 1 The corresponding technical effects achieved by executing the methods / steps in the example shown are not repeated here for the sake of brevity.

[0159] In one example, the device for fixing the base frequency ambiguity may further include a communication interface 703 and a bus 710. Figure 7 As shown, the processor 701, the memory 702, and the communication interface 703 are connected via a bus 710 and communicate with each other.

[0160] The communication interface 703 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present disclosure.

[0161] The bus 710 includes hardware, software, or both, coupling components of the baseband ambiguity fixation device to each other. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a Memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable busses or a combination of two or more of the above. Where appropriate, the bus 710 may include one or more buses. Although the embodiments of the present disclosure describe and illustrate specific buses, the present disclosure contemplates any suitable bus or interconnect.

[0162] In addition, in combination with the baseband ambiguity fixing method in the above embodiment, the embodiment of the present disclosure may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any baseband ambiguity fixing method in the above embodiment is implemented.

[0163] It should also be noted that the above reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present disclosure describes various aspects of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0164] The above is only a specific implementation of the present disclosure. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present disclosure is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present disclosure, and these modifications or replacements should be included in the protection scope of the present disclosure.

Claims

1. A method for fixing base frequency ambiguity, characterized in that: The method comprises: Based on the carrier observation data of the reference station and the mobile station, the initial value of the wide lane ambiguity is calculated; The baseband ambiguity initial value is filtered through the first joint observation equation, and the floating-point solution of the first baseband ambiguity obtained after the filtering is converted into a wide-lane ambiguity filtered value; the first joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity loose constraint equation, wherein the wide-lane ambiguity loose constraint equation is constrained by the wide-lane ambiguity initial value; Performing an ambiguity domain search on the wide lane ambiguity filter value to obtain a fixed wide lane ambiguity; The first baseband ambiguity is filtered again by a second joint observation equation to obtain a floating-point solution of the second baseband ambiguity; the second joint observation equation includes the ionosphere-free combined observation equation and a wide lane ambiguity tight constraint equation, wherein the wide lane ambiguity tight constraint equation is constrained by the fixed wide lane ambiguity; Performing an ambiguity domain search on the floating-point solution of the second baseband ambiguity to obtain a baseband ambiguity fixed solution of the carrier observation data; The filtering of the initial value of the baseband ambiguity by the first joint observation equation and converting the floating-point solution of the first baseband ambiguity obtained after the filtering into a wide-lane ambiguity filtering value specifically includes: The first joint observation equation is composed of the following ionosphere-free combined observation equation (1) and the wide-lane ambiguity loose constraint equation (2): Among them, φ1 and φ2 are the observed values ​​of carrier L1 frequency point and carrier L2 frequency point respectively. is the carrier phase observation value after ionospheric-free combination; f1 and f2 are the frequencies of carrier L1 frequency point and carrier L2 frequency point respectively; are the double-difference carrier phase observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; i, j represent the reference station respectively, N1, N2 represent the initial value of the fundamental frequency ambiguity of the observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively, Δ represents the single difference between stations; N mw is the initial value of the wide lane ambiguity; The filtering the first baseband ambiguity again through the second joint observation equation to obtain a floating-point solution value of the second baseband ambiguity includes: The second joint observation equation is composed of the following ionosphere-free combined observation equation (1) and the wide-lane ambiguity tight constraint equation (3): is the fixed wide-lane ambiguity.

2. The method for fixing the base frequency ambiguity according to claim 1, characterized in that: The calculation of the initial value of the wide lane ambiguity based on the carrier observation data of the reference station and the mobile station specifically includes: According to the dual-frequency carrier observation data of the reference station and the mobile station, the double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange to obtain the wide-lane ambiguity initial value.

3. The method for fixing base frequency ambiguity according to claim 1, characterized in that: The calculation of the initial value of the wide lane ambiguity based on the carrier observation data of the reference station and the mobile station specifically includes: According to the triple-frequency carrier observation data between the reference stations, two sets of ultra-wide lane ambiguities are obtained by smoothing and rounding pseudoranges; The two groups of the ultra-wide lane ambiguities are combined to form the initial wide lane ambiguity value.

4. The method for fixing base frequency ambiguity according to claim 1, characterized in that: The calculation of the initial value of the wide lane ambiguity based on the carrier observation data of the reference station and the mobile station specifically includes: When the carrier observation data only includes dual-frequency observation data, according to the dual-frequency carrier observation data of the reference station and the mobile station, a double-difference MW wide-lane ambiguity is solved by multi-epoch smoothing pseudorange to obtain the wide-lane ambiguity initial value; When the carrier observation data includes triple-frequency observation data, two sets of ultra-wide lane ambiguities are obtained according to the triple-frequency carrier observation data between the reference stations by smoothing the pseudorange and rounding, and the two sets of ultra-wide lane ambiguities are combined to form the wide lane ambiguity initial value.

5. The method for fixing base frequency ambiguity according to claim 1, characterized in that: After calculating the initial value of the wide lane ambiguity according to the carrier observation data of the reference station and the mobile station, and before filtering the initial value of the baseband ambiguity through the first joint observation equation and converting the floating point solution of the first baseband ambiguity obtained after filtering into a wide lane ambiguity filtered value, the method further includes: Extracting the initial values ​​of the wide lane ambiguity one by one, performing least squares solution, and obtaining corresponding multiple position data; Performing outlier detection according to the position data, deleting the initial wide lane ambiguity value corresponding to the position outlier, and obtaining the remaining initial wide lane ambiguity value after outlier detection; The wide lane ambiguity loose constraint equation is constrained by the initial value of the residual wide lane ambiguity.

6. A device for fixing base frequency ambiguity, characterized in that: The device comprises: The first calculation module is used to calculate the initial value of the wide lane ambiguity according to the carrier observation data of the reference station and the mobile station; A first filtering module is used to filter the baseband ambiguity initial value through a first joint observation equation, and convert the floating-point solution of the first baseband ambiguity obtained after the filtering into a wide-lane ambiguity filter value; the first joint observation equation includes an ionosphere-free combined observation equation and a wide-lane ambiguity loose constraint equation, wherein the wide-lane ambiguity loose constraint equation is constrained by the wide-lane ambiguity initial value; A first search module is used for performing an ambiguity domain search on the wide lane ambiguity filter value to obtain a fixed wide lane ambiguity; A second filtering module is configured to filter the first baseband ambiguity again through a second joint observation equation to obtain a floating-point solution of the second baseband ambiguity; the second joint observation equation includes the ionosphere-free combined observation equation and a wide lane ambiguity tight constraint equation, wherein the wide lane ambiguity tight constraint equation is constrained by the fixed wide lane ambiguity; A second search module is used to perform an ambiguity domain search on the floating point solution of the second base frequency ambiguity to obtain a base frequency ambiguity fixed solution of the carrier observation data; The first filtering module specifically comprises: a first joint observation equation consisting of the following ionosphere-free combined observation equation (1) and a wide-lane ambiguity loose constraint equation (2): Among them, φ1 and φ2 are the observed values ​​of carrier L1 frequency point and carrier L2 frequency point respectively. is the carrier phase observation value after ionospheric-free combination; f1 and f2 are the frequencies of carrier L1 frequency point and carrier L2 frequency point respectively; are the double-difference carrier phase observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively; i, j represent the reference station respectively, N1, N2 represent the initial value of the fundamental frequency ambiguity of the observation values ​​of carrier L1 frequency point and carrier L2 frequency point respectively, Δ represents the single difference between stations; N mw is the initial value of the wide lane ambiguity; The second filtering module specifically comprises: a second joint observation equation consisting of the following ionosphere-free combined observation equation (1) and the wide lane ambiguity tight constraint equation (3): is the fixed wide-lane ambiguity.

7. A device for fixing base frequency ambiguity, characterized in that: The device includes: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the method for fixing base frequency ambiguity as described in any one of claims 1-5.

8. A computer storage medium, characterized in that: The computer storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the method for fixing base frequency ambiguity as described in any one of claims 1 to 5 is implemented.

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