Satellite screening and ranking based GNSS integer ambiguity rapid determination method

Abstract

The application relates to a GNSS integer ambiguity fast determination method based on satellite screening and grading. The method comprises the following steps: screening and grading all observation satellites in a single epoch, and dividing the observation satellites into reference satellites, class I satellites and class II satellites; establishing double-difference carrier phase observation equations of class I satellite pairs and class II satellite pairs; solving double-difference integer ambiguities of the class I satellite pairs, obtaining double-difference integer ambiguities of the class I satellite pairs that pass the check, and then solving local solutions of the class I satellite pairs that can be used for positioning; substituting the local solutions of the class I satellite pairs that can be used for positioning into the double-difference carrier phase observation equations of the class II satellite pairs, and rounding to solve double-difference integer ambiguities of the class II satellite pairs; and determining GNSS single-epoch double-difference integer ambiguities according to the double-difference integer ambiguities of the class I satellite pairs and the class II satellite pairs.

Description

[0001] This application is a divisional application of the invention patent application filed on June 28, 2020, with application number 202010599437.7 and invention title "Rapid Determination Method of Integer Ambiguity of GNSS Single Epoch Double Difference". Technical Field

[0002] This invention relates to a rapid determination technology for GNSS single-epoch double-difference integer ambiguity, and particularly to the application of GNSS receivers in the field of safety monitoring of construction tower cranes (construction tower cranes or tower cranes). Background Technology

[0003] In the field of high-precision satellite positioning, GNSS carrier phase measurement is generally used. The carrier phase signal is a periodic sinusoidal signal, but phase measurement can only measure a portion of it less than one wavelength, thus introducing integer uncertainty, or integer ambiguity (also known as integer unknowns). Rapidly determining integer ambiguity is one of the keys to high-precision real-time dynamic satellite positioning.

[0004] To quickly determine integer unknowns, researchers in this field have made various efforts, developed various methods, and achieved many successes. However, in practical engineering applications, especially in tower crane systems for building construction, where higher precision real-time positioning is required, current methods still need improvement to reduce computational load and increase determination efficiency. Summary of the Invention

[0005] The present invention is made in view of the above-mentioned situation of the prior art, in order to solve one or more problems existing in the prior art, and at least provide an advantageous alternative.

[0006] According to one aspect of the present invention, a method for rapid determination of GNSS integer ambiguity based on satellite screening and classification is provided. The method includes: a satellite screening and classification step, which screens and classifies all observed satellites in a single epoch into reference satellites, Class I satellites, and Class II satellites. Class I satellites are a predetermined number of satellites with relatively good spatial geometric distribution, while Class II satellites are satellites other than the reference satellites and Class I satellites, representing satellites with relatively poor spatial geometric distribution; and a double-difference carrier phase observation equation establishment step, which establishes the double-difference carrier phase observation equations for Class I satellite pairs and the double-difference carrier phase observation equations for Class II satellite pairs. The process involves: wave phase observation equation; local solution steps for Type I satellite pairs, solving and verifying the double-difference integer ambiguity of the Type I satellite pairs to obtain the double-difference integer ambiguity of the Type I satellite pairs that has passed the verification, and then solving the local solution of the Type I satellite pairs that can be used for positioning; double-difference integer ambiguity determination steps for Type II satellite pairs, substituting the local solution of the Type I satellite pairs used for positioning into the double-difference carrier phase observation equation of the Type II satellite pairs, rounding and solving the double-difference integer ambiguity of the Type II satellite pairs; and determining the GNSS single-epoch double-difference integer ambiguity based on the double-difference integer ambiguity of the Type I satellite pairs and the double-difference integer ambiguity of the Type II satellite pairs.

[0007] According to another aspect of the present invention, a satellite positioning intelligent monitoring system for construction tower cranes is provided. The system includes a GNSS receiver for a reference station and a monitoring station, as well as a communication link. The GNSS receiver uses the aforementioned method for rapid determination of GNSS single-epoch double-difference integer ambiguity of construction tower cranes (tower cranes).

[0008] The GNSS receivers are a base station GNSS receiver installed near the construction site of the tower crane and a monitoring station GNSS receiver installed on the tower arm or tower body.

[0009] According to some embodiments of the present invention, integer unknowns can be solved more quickly and efficiently without affecting the positioning accuracy and reliability of the GNSS system.

[0010] According to some embodiments of the present invention, all observation satellites in a single epoch are screened and classified, and a predetermined number of Class I satellites are controlled, thereby significantly compressing the search space for double-difference ambiguities by satellites and accelerating the efficiency of GNSS single-epoch double-difference integer ambiguity resolution, thus appropriately increasing the GNSS receiver sampling rate. For example, the GNSS receiver sampling rate can be increased to 10Hz. Attached Figure Description

[0011] The invention can be better understood by referring to the accompanying drawings, which are illustrative and not intended to limit the scope of protection of the invention.

[0012] Figure 1A schematic flowchart of a method for rapid determination of GNSS single-epoch double-difference integer ambiguity according to an embodiment of the present invention is shown.

[0013] Figure 2 A schematic flowchart of a double-difference integer ambiguity resolution and verification method for Class I satellite pairs according to an embodiment of the present invention is shown.

[0014] Figure 3 A schematic block diagram of a GNSS single-epoch double-difference integer ambiguity rapid determination device according to one embodiment of the present invention is shown. Detailed Implementation

[0015] Figure 1 A schematic flowchart of a GNSS single-epoch double-difference integer ambiguity determination method according to an embodiment of the present invention is shown.

[0016] like Figure 1 The diagram illustrates a schematic flow of a method for rapid determination of GNSS single-epoch double-difference integer ambiguity according to an embodiment of the present invention. First, in step S10, satellite screening and classification are performed, that is, all observed satellites in a single epoch are screened and classified into reference satellites, Class I satellites, and Class II satellites. Class I satellites are a predetermined number of satellites with relatively good spatial geometric distribution, while Class II satellites are satellites other than the reference satellites and Class I satellites, and are satellites with relatively poor spatial geometric distribution.

[0017] According to one implementation, in step S10, firstly, the satellite with the largest elevation angle is determined as the reference satellite; then, for the satellites other than the reference satellite, the azimuth difference between each pair of adjacent satellites is compared to obtain the two satellites with the smallest azimuth difference, and the satellite with the smaller elevation angle among these two satellites is retained. This process is repeated to obtain a predetermined number of satellites that are determined as Class I satellites; finally, the remaining satellites are determined as Class II satellites.

[0018] According to one embodiment, the predetermined quantity is 5-7. According to another embodiment, the predetermined quantity can be determined based on the GNSS receiver sampling interval as follows:

[0019]

[0020] Where SatNum is the predetermined quantity, and T is the GNSS receiver sampling interval.

[0021] Where: F is the GNSS receiver sampling rate.

[0022] Then, in step S20, the double-difference carrier phase observation equation is established for Class I satellite pairs and Class II satellite pairs.

[0023] According to one implementation, in step S20, the double-difference carrier phase observation equation for Class I satellite pairs is established as follows:

[0024]

[0025] And the following establishes the double-difference carrier phase observation equations for Class II satellite pairs:

[0026]

[0027] Where s represents the total number of Class I satellite pairs, j1 represents Class I satellites (j1 = 1, 2, ..., s), k represents the total number of Class II satellite pairs, j2 represents Class II satellites (j2 = 1, 2, ..., k), i represents the reference satellite, λ represents the wavelength of the frequency signal, subscript b represents the base station, and subscript m represents the monitoring station. This represents the double-difference carrier phase observations for a Class I satellite pair. This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class I satellite pair. and This represents the cosine coefficient of the satellite-to-ground distance direction for a Class I satellite pair. This represents the double-difference integer ambiguity of a Class I satellite pair. This represents the double-difference carrier phase observations for a Class II satellite pair. This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class II satellite pair. and This represents the cosine coefficient of the satellite-to-ground distance direction for Class II satellite pairs. This represents the double-difference integer ambiguity of a Class II satellite pair. and 1+s+k is the three-dimensional coordinate correction number of monitoring station m, where 1+s+k is a positive integer, representing the total number of satellites observed in this epoch.

[0028] Next, in the local solution step of the Type I satellite pair in step S30, the double-difference integer ambiguity of the Type I satellite pair is solved and checked to obtain the double-difference integer ambiguity of the Type I satellite pair that has passed the check, and then the local solution of the Type I satellite pair that can be used for positioning is solved.

[0029] According to one implementation, such as Figure 2 As shown, the double-difference integer ambiguity resolution for Class I satellite pairs is performed in S30 as follows:

[0030] Step S1: Determine the primary frequency signal and the secondary frequency signal. In one embodiment, the first frequency signal of the GPS, GLONASS, BDS, or Galileo system, or a combined frequency signal formed by linearly combining the first frequency signal with the second and / or third frequency signals, is determined as the primary frequency signal. The second frequency signal, third frequency signal, or combined frequency signal other than the primary frequency signal is determined as the secondary frequency signal. The first frequency signal of the GPS, GLONASS, BDS, or Galileo system is the primary frequency signal of the GPS, GLONASS, BDS, or Galileo system.

[0031] Step S2: Establish the double-difference carrier phase observation equation for the main frequency signal and the double-difference carrier phase observation equation for the auxiliary frequency signal.

[0032] According to one implementation, the double-difference carrier phase observation equations for the primary frequency signal and the secondary frequency signal are established as follows:

[0033]

[0034] Where λ is the wavelength of the frequency signal, including the wavelengths of the primary frequency signal and the secondary frequency signal. When λ is the wavelength of the primary frequency signal, a double-difference carrier phase observation equation for the primary frequency signal is established; when λ is the wavelength of the secondary frequency signal, a double-difference carrier phase observation equation for the secondary frequency signal is established.

[0035] Wherein, subscript b represents the base station, subscript m represents the monitoring station, superscript i represents the reference satellite with the largest satellite elevation angle, and superscript j represents satellites other than the reference satellite, j1 = 1, 2, ..., s. These are double-difference carrier phase observations for a Class I satellite pair. This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class I satellite pair. and For Class I satellite pairs, the cosine coefficient of the satellite-to-ground distance direction is... For double-difference integer-cycle ambiguity of Class I satellite pairs, and s is the three-dimensional coordinate correction number of monitoring station m, where s is a positive integer and refers to the total number of Class I satellite pairs among the satellites observed in this epoch;

[0036] Step S3: Using the double-difference carrier phase observation equation of the auxiliary frequency signal, determine the candidate group of double-difference integer ambiguity of the main frequency signal.

[0037] According to one implementation, candidate groups for the double-difference integer ambiguity of the main frequency signal are determined as follows:

[0038] First, calculate the initial value of the double-difference integer ambiguity of the secondary frequency signal as follows:

[0039]

[0040] in, Auxiliary frequency signal f Fu The initial value of the double-difference integer ambiguity. Auxiliary frequency signal f Fu The difference between the observed inter-satellite distance and the satellite-to-Earth distance. Auxiliary frequency signal f Fu The double-difference carrier phase observation, λ fFu Auxiliary frequency signal f Fu The wavelength;

[0041] Secondly, using the initial value, candidate values ​​for the double-difference integer ambiguity of the auxiliary frequency signal are determined:

[0042] For satellite pairs i and j1,

[0043]

[0044] Where i is the reference satellite, j1 is a Class I satellite, j1 = 1, 2, ..., s, E Length This refers to the band length of the error band for Class I satellites, i and j1. Where: σ is the standard error of the pseudorange difference observations of a single epoch of GNSS. The wavelength of the secondary frequency signal is l = 2 to 5, and int(·) represents the integer operation. Auxiliary frequency signal f Fu Candidate values ​​for double-difference integer ambiguity. w is the number of candidate values;

[0045] Secondly, using the following relational formula, of Determine the main frequency signal f Zhu Candidate values ​​for double-difference integer ambiguity:

[0046]

[0047] in:

[0048] Where u represents the error band. Main frequency signal f Zhu Residual error and measurement noise after inter-satellite double difference Auxiliary frequency signal f Fu Residual error and measurement noise after inter-satellite double difference The wavelength of the main frequency signal. The wavelength of the secondary frequency signal. Auxiliary frequency signal f Fu Candidate values ​​for double-difference integer ambiguity, E Wide The bandwidth of the error band for Class I satellites i and j1 can be determined in one implementation as follows: Wide :

[0049] Where: L bm The baseline length L between base station b and monitoring station m bm ,

[0050] Main frequency signal f Z h Candidate values ​​for double-difference integer ambiguity. v represents the number of candidate values;

[0051] Finally, the candidate values ​​for the double-difference integer ambiguity of the main frequency signal of the Class I satellite pair are expressed as follows:

[0052]

[0053] Perform on the candidate values By arranging and combining groups, candidate groups of double-difference integer ambiguities of the main frequency signals of all satellite pairs in a single epoch are obtained, where t represents the total number of candidate groups;

[0054] Step S4: Using the double-difference carrier phase observation equation of the main frequency signal, perform a significance test on the candidate groups, and determine the candidate groups that pass the significance test as the optimal group. According to one embodiment, the optimal group of double-difference integer ambiguity of the main frequency signal is determined as follows:

[0055] First, the t candidate groups of the double-difference integer ambiguity of the main frequency signal are substituted sequentially into the double-difference carrier phase observation equation of the main frequency signal. According to the least squares indirect adjustment principle, the error equation of the corresponding double-difference carrier phase observation equation of the main frequency signal is:

[0056]

[0057] Written in matrix form:

[0058]

[0059] in,

[0060] The subscript b indicates the base station, the subscript m indicates the monitoring station, the superscript i indicates the reference satellite with the largest elevation angle, and the superscript j1 indicates a satellite other than the reference satellite, where j1 = 1, 2, ..., s. These are double-difference carrier phase observations for a Class I satellite pair. The wavelength of the main frequency signal. Candidate groups for the double-difference integer ambiguity of the main frequency signal of Class I satellite pairs; This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class I satellite pair. and The cosine coefficient of the satellite-to-Earth distance direction. The residuals of the double-difference carrier phase observations for a Class I satellite pair. The constant term in the double-difference carrier phase observation equation for the main frequency signal. and Let m be the correction value for the three-dimensional coordinates of monitoring station m;

[0061] Secondly, based on the least squares parameter estimation method, the unit weight variance factor of the double-difference carrier phase observation equation of the main frequency signal is calculated as follows:

[0062]

[0063] Where: s is the total number of Class I satellite pairs, and P is the weight matrix of the double-difference carrier phase observations of Class I satellite pairs;

[0064] From t candidate groups, t unit weight variance factors can be calculated, which can be represented by a set.

[0065] Next, sort the elements in set {Ω} in ascending order to obtain set {Ω} = {Ω1 Ω2 …Ω}. t Construct significance test values:

[0066]

[0067] The candidate group of double-difference integer ambiguities corresponding to Ω1 with ratio > R is determined as the optimal group, i.e. Where R = 1.8 to 3;

[0068] Step S5: Using the double-difference carrier phase observation equation of the main frequency signal, determine the rounding group of the double-difference integer ambiguity of the main frequency signal. According to one embodiment, the rounding group of the double-difference integer ambiguity of the main frequency signal is determined as follows:

[0069] First, the optimal group of double-difference integer ambiguities of the determined main frequency signal is... Substituting the double-difference carrier phase observation equation of the main frequency signal, the three-dimensional coordinate correction of monitoring station m is calculated using the least squares parameter indirect adjustment method. The three-dimensional coordinate correction is then substituted back into the double-difference carrier phase observation equation of the main frequency signal to solve the real solution of the double-difference integer ambiguity of the main frequency signal as follows:

[0070]

[0071] Then, the real number solution is rounded according to the principle of "rounding up if odd, not if even", to obtain the rounded set of the double-difference integer ambiguity of the main frequency signal as follows:

[0072]

[0073] in, The integer set of the double-difference integer ambiguity of the main frequency signal;

[0074] Step S6: Check the consistency between the optimal group and the rounding group. According to one embodiment, the consistency between the optimal group and the rounding group of the double-difference integer ambiguity of the main frequency signal is checked as follows:

[0075] For the double-difference integer ambiguity of i and j1 for Class I satellites, determine the optimal group. In the integer group Whether they are equal, j1 = 1, 2, ..., s;

[0076] if If the double-difference integer ambiguity resolution check for satellite pair I is passed, it means that the double-difference integer ambiguity resolution for satellite pair i and j1 is successful.

[0077] if If the double-difference integer ambiguity resolution check for satellite pair I is not passed, it means that the double-difference integer ambiguity resolution for satellite pair i and j1 failed.

[0078] Step S7: Obtain the double-difference integer ambiguity of the approved Class I satellite pairs, i.e.:

[0079] According to one implementation, if the double-difference integer ambiguity resolution check of the Type I satellite pair fails in step S6, the method further includes updating the double-difference carrier phase observation equations of the Type I and Type II satellites and the Type I and Type II satellite pairs, and using the updated equations to perform local solution calculation.

[0080] According to one implementation, Class I and Class II satellites are updated as follows: satellite j1 that successfully resolves double-difference integer ambiguity is retained in Class I satellites; conversely, satellite j1 that fails to resolve double-difference integer ambiguity is removed from Class I satellites and reclassified into Class II satellites.

[0081] According to one implementation, the double-difference carrier phase observation equations for Class I satellite pairs are updated as follows:

[0082]

[0083] Where: s1≤s

[0084] And the following updates the double-difference carrier phase observation equations for Class II satellite pairs:

[0085]

[0086] Where: k2≥k

[0087] Wherein, s1 represents the total number of updated Class I satellite pairs, s represents the total number of original Class I satellite pairs, j1 represents Class I satellites, j1 = 1, 2, ..., s1, k1 represents the total number of updated Class II satellite pairs, k represents the total number of original Class II satellite pairs, j2 represents Class II satellites, j2 = 1, 2, ..., k2, i represents the reference satellite, λ represents the wavelength of the frequency signal, subscript b represents the reference station, and subscript m represents the monitoring station. This represents the double-difference carrier phase observations for a Class I satellite pair. This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class I satellite pair. and This represents the cosine coefficient of the satellite-to-ground distance direction for a Class I satellite pair. This represents the double-difference integer ambiguity of a Class I satellite pair. This represents the double-difference carrier phase observations for a Class II satellite pair. This represents the difference between the observed inter-satellite distance and the satellite-to-ground distance for a Class II satellite pair. and This represents the cosine coefficient of the satellite-to-ground distance direction for Class II satellite pairs. This represents the double-difference integer ambiguity of a Class II satellite pair. and Let be the three-dimensional coordinate correction of monitoring station m, and 1+s1+k2 be a positive integer, referring to the total number of satellites observed in this epoch, 1+s1+k2=1+s+k.

[0088] Next, in the Type II satellite pair double-difference integer ambiguity determination step S40, the local solution used for positioning of the Type I satellite pair is substituted into the double-difference carrier phase observation equation of the Type II satellite pair, and the double-difference integer ambiguity of the Type II satellite pair is calculated by rounding.

[0089] In one implementation, the real solution for the double-difference integer ambiguity of a Type II satellite pair is calculated as follows:

[0090]

[0091] Then, the real number solution is rounded according to the principle of "rounding up if odd, not if even", to obtain the rounded set of the double-difference integer ambiguity of the frequency signal as follows:

[0092]

[0093] in, For the integer solutions of the double-difference integer ambiguity of the Class II satellite pair.

[0094] Then, in step S50, the GNSS single epoch double-difference integer ambiguity is determined based on the double-difference integer ambiguity of the Type I satellite pair and the double-difference integer ambiguity of the Type II satellite pair.

[0095] According to one implementation, the combined double-difference integer-cycle ambiguity of the verified Class I satellite pairs is... Double-difference integer ambiguity of Class II satellite pairs Directly determine the GNSS single-epoch double-difference integer ambiguity, i.e.:

[0096] According to one embodiment of the present invention, the method can be applied to real-time positioning with a GNSS receiver data sampling rate of not less than 1 Hz.

[0097] The aforementioned method of the present invention can be applied to a satellite positioning intelligent monitoring system for construction tower cranes. The system includes a GNSS receiver at a base station and a monitoring station, as well as a communication link. The GNSS receiver uses the aforementioned method for rapid determination of GNSS single-epoch double-difference integer ambiguity for construction tower cranes. The GNSS receiver is installed at a base station near the construction site of the tower crane and at a monitoring station on the tower arm or tower body.

[0098] The intelligent satellite positioning monitoring system for building tower cranes may include a GNSS single-epoch double-difference integer ambiguity rapid determination device. Figure 3 A schematic block diagram of a GNSS single-epoch double-difference integer ambiguity rapid determination device according to one embodiment of the present invention is shown. Figure 3 As shown, the device includes:

[0099] The satellite screening and grading processing unit 100 screens and grades all observation satellites in a single epoch, dividing them into reference satellites, Class I satellites, and Class II satellites. Class I satellites are a predetermined number of satellites with relatively good spatial geometric distribution, while Class II satellites are satellites other than reference satellites and Class I satellites, and have relatively poor spatial geometric distribution.

[0100] Unit 200 establishes the double-difference carrier phase observation equation for Class I satellite pairs and the double-difference carrier phase observation equation for Class II satellite pairs.

[0101] The local solution unit 300 for the Class I satellite pair solves the double-difference integer ambiguity of the Class I satellite pair to obtain the double-difference integer ambiguity of the Class I satellite pair that has passed the check, and then solves the local solution of the Class I satellite pair that can be used for positioning.

[0102] The Type II satellite pair double-difference integer ambiguity determination unit 400 substitutes the local solution used for positioning of the Type I satellite pair into the double-difference carrier phase observation equation of the Type II satellite pair, and calculates the double-difference integer ambiguity of the Type II satellite pair by rounding down the solution; and

[0103] The GNSS single-epoch double-difference integer ambiguity rapid determination unit 500 determines the GNSS single-epoch double-difference integer ambiguity based on the double-difference integer ambiguity of Class I satellite pairs and Class II satellite pairs.

[0104] The units described above respectively execute the aforementioned satellite screening and grading processing step S10, the double-difference carrier phase observation equation establishment step S20, the local solution step S30 for Class I satellites, the double-difference integer ambiguity determination step S40 for Class II satellites, and the rapid determination step S50 for GNSS single-epoch double-difference integer ambiguity. For details, please refer to the descriptions of the corresponding steps above. The units and devices described above can be implemented individually or in combination using programmed independent chips, specially manufactured chips, field-programmable gate arrays, or other hardware. They can also be implemented using a machine with computing capabilities combined with software.

[0105] The above detailed description of the invention is merely intended to provide those skilled in the art with further information for carrying out preferred aspects of the invention, and does not limit the scope of the invention. Only the claims are used to define the scope of protection of the invention. Therefore, the combination of features and steps in the foregoing detailed description is not necessary for carrying out the invention in the broadest possible sense, and is alternatively taught only for representative embodiments of the invention as described in a particularly detailed description. Furthermore, various different features taught in the specification can be combined in various ways to obtain additional useful embodiments of the invention; however, these ways are not specifically exemplified.

Claims

1. A method for fast determination of GNSS single epoch double-difference integer ambiguity based on satellite screening and ranking, the method comprising: a satellite screening and ranking step, screening and ranking all observed satellites in a single epoch into reference satellites, class I satellites and class II satellites, the class I satellites being a predetermined number of satellites with relatively better spatial geometry distribution, and the class II satellites being satellites other than the reference satellites and the class I satellites, and being satellites with relatively worse spatial geometry distribution; a double-difference carrier phase observation equation establishment step, establishing double-difference carrier phase observation equations for pairs of class I satellites and pairs of class II satellites; a class I satellite pair local solution step, solving double-difference integer ambiguities for the pairs of class I satellites, obtaining double-difference integer ambiguities for the pairs of class I satellites that pass the check, and then solving local solutions of the pairs of class I satellites that can be used for positioning; a class II satellite pair double-difference integer ambiguity determination step, substituting the local solutions of the pairs of class I satellites that can be used for positioning into the double-difference carrier phase observation equations for the pairs of class II satellites, and solving double-difference integer ambiguities for the pairs of class II satellites; and a GNSS single epoch double-difference integer ambiguity fast determination step, determining GNSS single epoch double-difference integer ambiguities according to the double-difference integer ambiguities for the pairs of class I satellites and the double-difference integer ambiguities for the pairs of class II satellites, wherein in the class I satellite pair local solution step, the double-difference integer ambiguities for the pairs of class I satellites are solved as follows: Step S1, determining a primary frequency signal and a secondary frequency signal, determining a first frequency signal of a GPS, GLONASS, BDS or Galileo system, or a combined frequency signal formed by linear combination of the first frequency signal and a second frequency signal and / or a third frequency signal as the primary frequency signal, and determining the second frequency signal or the third frequency signal or the combined frequency signal other than the primary frequency signal as the secondary frequency signal, the first frequency signal of the GPS, GLONASS, BDS or Galileo system being a primary frequency signal of the GPS, GLONASS, BDS or Galileo system; Step S2, establishing double-difference carrier phase observation equations for the primary frequency signal and the secondary frequency signal, the double-difference carrier phase observation equations for the primary frequency signal and the secondary frequency signal are established as follows: wherein λ is the wavelength of the frequency signal, including the wavelength of the primary frequency signal and the wavelength of the secondary frequency signal, when λ is the wavelength of the primary frequency signal, the double-difference carrier phase observation equation established is for the primary frequency signal, and when λ is the wavelength of the secondary frequency signal, the double-difference carrier phase observation equation established is for the secondary frequency signal, wherein subscript b represents a reference station, subscript m represents a monitoring station, superscript i represents a reference satellite with the largest satellite elevation angle, superscript j represents a satellite other than the reference satellite, j1=1,2,…,s, is a double-difference carrier phase observation value of a satellite pair of the first type, is a difference between a station-satellite distance observation value and a satellite-ground distance difference of the satellite pair of the first type, and is a satellite-ground distance direction cosine coefficient of the satellite pair of the first type, is a double-difference integer ambiguity of the satellite pair of the first type, and is a three-dimensional coordinate correction of the monitoring station m, s is a positive integer, and indicates the total number of the satellite pair of the first type in the current epoch. Step S3, determining a candidate group of double-difference integer ambiguities for the primary frequency signal by using the double-difference carrier phase observation equation for the secondary frequency signal, the candidate group of double-difference integer ambiguities for the primary frequency signal is determined as follows: firstly, an initial value of the double-difference integer ambiguity for the secondary frequency signal is calculated as follows: wherein is a double-difference integer ambiguity initial value for the secondary frequency signal f Fu , is a difference between a station-to-satellite range observation value for the secondary frequency signal f Fu , is a double-difference carrier phase observation value for the secondary frequency signal f Fu , is a wavelength for the secondary frequency signal f Fu . secondly, a candidate value of the double-difference integer ambiguity for the secondary frequency signal is determined by using the initial value: for satellite pairs i and j1, wherein i represents a reference satellite, j1 is a satellite of the first type, j1 = 1, 2, …, s, E Length denotes the length of the error band of the satellite of the first type i and j1, is an auxiliary frequency signal f Fu of the double-difference integer ambiguity of the carrier phase, w is the number of candidate values; Again, using the relation the double-difference integer ambiguity candidate value for the primary frequency signal f Zhu is determined as​ wherein: where u is the error band, is the main frequency signal f Zhu the residual error and measurement noise after station inter- satellite double difference, is the auxiliary frequency signal f Fu the residual error and measurement noise after station inter- satellite double difference, is the wavelength of the main frequency signal, is the wavelength of the auxiliary frequency signal, is the auxiliary frequency signal f Fu the double-difference integer ambiguity candidate value of E Wide denotes the bandwidth of the error band of the class I satellite pair i and j1, is the double-difference integer ambiguity candidate value of E Zhu v is the number of candidate values;​ Finally, the candidate value of the double-difference integer ambiguity of the main frequency signal of the satellite pair of the first type is expressed as follows: performing the following operations on the candidate values obtaining a candidate set of double-difference integer ambiguity of the main frequency signal of the satellite pair of the first type, t represents the total number of candidate sets; In step S4, the candidate group is subjected to a significance test by using the double-difference carrier phase observation equation of the main frequency signal, and the candidate group that passes the significance test is determined as the optimal group, The optimal group of the double-difference integer ambiguity of the main frequency signal is determined as follows: Firstly, the t candidate groups of the double-difference integer ambiguity of the main frequency signal are sequentially substituted into the double-difference carrier phase observation equation of the main frequency signal, and the error equation of the corresponding double-difference carrier phase observation equation of the main frequency signal is calculated according to the least squares indirect adjustment principle: The matrix form is written as: wherein, subscript b denotes a reference station, subscript m denotes a monitoring station, superscript i denotes a reference satellite with the largest satellite elevation angle, superscript j1 denotes a satellite of the first type, j1 = 1, 2, …, s, is a double-difference carrier phase observation value of a satellite pair of the first type, is a wavelength of a main frequency signal, is a candidate set of double-difference integer ambiguity of the main frequency signal of the satellite pair of the first type; is a difference between a station-satellite distance observation value and a geodetic distance difference of the satellite pair of the first type, and is a geodetic distance direction cosine coefficient, is a residual of the double-difference carrier phase observation value of the satellite pair of the first type, is a constant term of a double-difference carrier phase observation equation of the main frequency signal, and is a three-dimensional coordinate correction of the monitoring station m; Secondly, the unit weight variance factor of the double-difference carrier phase observation equation of the main frequency signal is calculated according to the least squares parameter estimation method as follows: Wherein: s is the total number of the satellite pair of the first type, and P is the weight matrix of the double-difference carrier phase observation value of the satellite pair of the first type; From the t sets of candidate groups, t unit-weight variance factors can be computed, denoted by the set Then, the elements in the set {Ω} are sorted from small to large, and the set {Ω} = {Ω1Ω2…Ω t} is obtained, and the significance test value is constructed: The candidate group of double-difference integer ambiguity corresponding to Ω1 with ratio > R is determined as the optimal group, that is wherein R = 1.8-3; In step S5, the double-difference integer ambiguity of the main frequency signal is determined by using the double-difference carrier phase observation equation of the main frequency signal, The rounding group of the double-difference integer ambiguity of the main frequency signal is determined as follows: First, the optimal group of double-difference integer ambiguity of the determined main frequency signal is calculated The double-difference carrier phase observation equation of the main frequency signal is substituted, the least square parameter indirect adjustment method is adopted, the three-dimensional coordinate correction number of the monitoring station m is calculated and obtained, and the three-dimensional coordinate correction number is substituted back to the double-difference carrier phase observation equation of the main frequency signal. The real solution of the double-difference integer ambiguity of the main frequency signal is calculated as follows: Then, the real solution is rounded according to the principle of "rounding up six and rounding down four, rounding in when five is encountered, and not rounding in when even number is encountered", and the rounding group of the double-difference integer ambiguity of the main frequency signal is obtained as follows: wherein an integer number of double-difference cycle slips of the primary frequency signal; In step S6, the consistency of the optimal group and the rounding group is checked, The consistency of the optimal group and the rounding group of the double-difference integer ambiguity of the main frequency signal is checked as follows: For the double-difference integer ambiguity of i and j1 of Class I satellite, judge whether the optimal group is equal to the rounding group or not, j1 = 1, 2, …, s ​ If then the double-difference integer ambiguity resolution check for class I satellite pairs is passed, indicating that the double-difference integer ambiguity resolution for satellite pair i and j1is successful; If then it is determined that the double-difference integer ambiguity resolution check for the class I satellite pair fails, indicating that the double-difference integer ambiguity resolution for the satellite pair i and j1failed. Step S7, obtain the double-difference integer ambiguity of the Class I satellite pair that passes the check, that is:

2. The method of claim 1, wherein, The satellite screening and grading processing step includes: Firstly, the satellite with the largest satellite elevation angle is determined as the reference satellite; Secondly, for the satellites other than the reference satellite, the satellite azimuth angle difference comparison is performed on the two adjacent satellites, the two satellites with the smallest satellite azimuth angle difference are obtained, and the satellite with the smaller satellite elevation angle is retained, and then the process is repeated to obtain a predetermined number of satellites as the satellite of the first type; Finally, the remaining satellites are determined as the satellite of the second type.

3. The method of claim 1, wherein, If the double-difference integer ambiguity solution of the satellite pair of the first type fails in step S6, the method further includes: Updating the satellite of the first type and the satellite of the second type, retaining the satellite j1 that passes the double-difference integer ambiguity solution in the satellite of the first type, and putting the satellite j1 that fails the double-difference integer ambiguity solution into the satellite of the second type, Updating the double-difference carrier phase observation equation of the satellite pair of the first type: Wherein: s1≤s And updating the double-difference carrier phase observation equation of the satellite pair of the second type: Wherein: k2≥k where s1 is the total number of updated satellite pairs of class I, s is the total number of original satellite pairs of class I, j1 represents a satellite of class I, j1 = 1, 2, …, s1, k2 is the total number of updated satellite pairs of class II, k is the total number of original satellite pairs of class II, j2 represents a satellite of class II, j2 = 1, 2, …, k2, i represents a reference satellite, λ is the wavelength of a frequency signal, the subscript b represents a base station, and the subscript m represents a monitoring station, represents a double-difference carrier phase observation value of a satellite pair of class I, represents a difference between an inter-station distance observation value and a satellite-earth distance difference of a satellite pair of class I, and represents a satellite-earth distance direction cosine coefficient of a satellite pair of class I, represents a double-difference integer ambiguity of a satellite pair of class I, represents a double-difference carrier phase observation value of a satellite pair of class II, represents a difference between an inter-station distance observation value and a satellite-earth distance difference of a satellite pair of class II, and represents a satellite-earth distance direction cosine coefficient of a satellite pair of class II, represents a double-difference integer ambiguity of a satellite pair of class II, and is a three-dimensional coordinate correction of the monitoring station m, 1 + s1 + k2 is a positive integer, indicates the total number of satellites observed at the current epoch, and 1 + s1 + k2 = 1 + s + k.

4. The method of claim 1, wherein, The local solution of the satellite pair of the first type that can be used for positioning is solved as follows: The double-difference integer ambiguity of the satellite pair of the first type that passes the check is substituted into the double-difference carrier phase observation equation of the satellite pair of the first type that is re-established, and the least squares parameter estimation method is used to obtain the local solution of the satellite pair of the first type that can be used for positioning.

5. The method of claim 4, wherein, In the double-difference integer ambiguity determination step of the satellite pair of the second type, the real solution of the double-difference integer ambiguity of the satellite pair of the second type is solved as follows: Then, the real solution is rounded according to the principle of "rounding up six and rounding down four, rounding in when five is encountered, and not rounding in when even number is encountered", and the rounding group of the double-difference integer ambiguity of the main frequency signal is obtained as follows: wherein is the integer solution of the double-difference integer ambiguity for the pair of class II satellites.

6. The method of claim 1, wherein, E is determined as follows Wide : wherein: L bm is the baseline length formed between the reference station b and the monitoring station m.

7. The method of claim 1, wherein, E is determined as follows Length : wherein: σ is the mean error of GNSS single-epoch pseudorange difference observation value, is the wavelength of the auxiliary frequency signal, l = 2 ~ 5, and int(·) represents the rounding operation.

Images