GNSS integer ambiguity resolution checking method based on primary frequency and secondary frequency

Abstract

The application relates to a GNSS integer ambiguity resolution method based on a main frequency and an auxiliary frequency. The method comprises the following steps: determining a main frequency signal and an auxiliary frequency signal; establishing a double-difference carrier phase observation equation of the main frequency signal and the auxiliary frequency signal; determining a candidate group of double-difference integer ambiguity of the main frequency signal by using the double-difference carrier phase observation equation of the auxiliary frequency signal; performing a significance test on the candidate group by using the double-difference carrier phase observation equation of the main frequency signal, so as to determine an optimal group; determining an integer group of double-difference integer ambiguity of the main frequency signal by using the double-difference carrier phase observation equation of the main frequency signal; and checking the consistency of the optimal group and the integer group. The application provides a reliable, simple and effective checking algorithm for fast determination of GNSS single-epoch double-difference integer ambiguity, and has important significance when the GNSS receiver is applied to the field of safety monitoring of construction tower cranes.

Description

[0001] This application is a divisional application of the invention patent application with the application date of June 28, 2020, the application number of 202010599281.2, and the invention name of "GNSS single epoch double difference integer ambiguity resolution verification method, receiver and tower crane". TECHNICAL FIELD

[0002] The present application relates to the application of GNSS receiver in the field of construction tower crane (construction tower crane or tower crane) safety monitoring, and in particular to the resolution verification of GNSS single epoch double difference integer ambiguity fast determination technology. BACKGROUND

[0003] Compared with the GNSS pseudorange measurement method, the GNSS carrier phase measurement method has higher accuracy. Therefore, in the field of high-precision satellite positioning, the GNSS carrier phase measurement method is generally used. The carrier phase signal is a periodic sinusoidal signal, and the phase measurement can only measure the part less than one wavelength, so there is an integer ambiguity problem (also known as integer unknown number) problem. The fast determination of integer ambiguity is one of the keys to high-precision satellite real-time kinematic positioning.

[0004] In order to quickly determine the integer unknown number, the workers in the field have made various efforts, developed various methods, and achieved a lot of achievements. However, in actual engineering application practice, especially in the field of construction tower crane safety monitoring with high precision requirements, the current method still needs to be improved. SUMMARY

[0005] The present application is made in view of the above situation of the prior art, in order to solve one or more problems existing in the prior art, and at least provide a beneficial option.

[0006] According to one aspect of the present application, a GNSS integer ambiguity resolution verification method based on a main frequency and an auxiliary frequency is provided, the method comprising: determining a main frequency signal and an auxiliary frequency signal; establishing a double difference carrier phase observation equation of the main frequency signal and a double difference carrier phase observation equation of the auxiliary frequency signal; using the double difference carrier phase observation equation of the auxiliary frequency signal, determining a candidate group of double difference integer ambiguity of the main frequency signal; using the double difference carrier phase observation equation of the main frequency signal, performing a significance test on the candidate group, and determining the candidate group that passes the significance test as an optimal group; using the double difference carrier phase observation equation of the main frequency signal, determining an integer group of double difference integer ambiguity of the main frequency signal; and verifying the consistency of the optimal group and the integer group.

[0007] According to another aspect of the present invention, a GNSS receiver is provided for use with GPS, BDS, GLONASS, Galileo systems, or multi-system GNSS, characterized in that it uses the method described above. Multi-system GNSS refers to a GNSS system comprising a combination of two or more systems from GPS, BDS, GLONASS, or Galileo systems.

[0008] According to another aspect of the invention, a tower crane is provided that uses the receiver described above, wherein the receiver is installed at a base station GNSS receiver near the construction site of the tower crane and at a monitoring station GNSS receiver on the tower arm or tower body.

[0009] According to the embodiments of the present invention, not only can integer unknowns be solved quickly, but their correctness can also be reasonably judged, which can effectively improve the positioning accuracy and positioning reliability of the GNSS system. Attached Figure Description

[0010] 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.

[0011] Figure 1 The illustration shows a schematic flow of a GNSS single-epoch double-difference integer ambiguity resolution and verification method for applying a GNSS receiver to a construction tower crane according to an embodiment of the present invention.

[0012] Figure 2 A schematic block diagram of a GNSS single-epoch double-difference integer ambiguity resolution and verification device according to one embodiment of the present invention is shown. Detailed Implementation

[0013] Figure 1 This paper illustrates a schematic flowchart of a GNSS single-epoch double-difference integer ambiguity resolution and verification method for applying a GNSS receiver to a construction tower crane, according to one embodiment of the present invention. Figure 1As shown, according to one embodiment of the present invention, the GNSS single-epoch double-difference integer ambiguity resolution and verification method for tower cranes first determines the main frequency signal and the auxiliary frequency signal in step S10. The main frequency signal is mainly used for positioning, and the auxiliary frequency signal is mainly used for rapid integer ambiguity resolution. According to one embodiment, the GPS L1 frequency signal (first frequency signal), BDS B1 frequency signal, GLONASS L1 frequency signal, or Galileo E1 frequency signal can be determined as the main frequency signal based on the satellite positioning system corresponding to the GNSS system, while frequency signals other than the main frequency signal are determined as auxiliary frequency signals. Alternatively, multiple frequency signals from a single system (e.g., L1, L2, or L5 of a GPS system) can be linearly combined using wide-lane combination, narrow-lane combination, or ultra-wide-lane combination to form a new combined frequency signal, which is then determined as the main frequency signal, while frequency signals other than the main frequency signal are determined as auxiliary frequency signals. According to one embodiment, a single original frequency signal with high observation accuracy, or a new combined frequency signal formed by linearly combining multiple original frequency signals, is determined as the main frequency signal.

[0014] According to one embodiment, the first frequency signal of the GPS, GLONASS, BDS, or Galileo system, or the combined frequency signal formed by linearly combining the first frequency signal with the second and / or third frequency signals, is determined as the main frequency signal, while the second frequency signal, the third frequency signal, or the combined frequency signal other than the main frequency signal is determined as the auxiliary frequency signal. The first frequency signal of the GPS, GLONASS, BDS, or Galileo system is the main frequency signal of the GPS, GLONASS, BDS, or Galileo system.

[0015] Then, in step S20, the double-difference carrier phase observation equations for the main frequency signal and the double-difference carrier phase observation equations for the auxiliary frequency signal are constructed.

[0016] 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:

[0017]

[0018] 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.

[0019] 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, j = 1, 2, ..., i-1, i+1, ..., k. This represents the double-difference carrier phase observation value. This represents the difference between the observed inter-satellite distance and the satellite-to-Earth distance. and This represents the cosine coefficient of the satellite-to-Earth distance direction. and Let m be the correction value for the three-dimensional coordinates of monitoring station m. This represents the double-difference integer ambiguity, where k is a positive integer representing the total number of satellites observed in this epoch.

[0020] Next, in step S30, the candidate group of double-difference integer ambiguity of the main frequency signal is determined by using the double-difference carrier phase observation equation of the auxiliary frequency signal.

[0021] According to one implementation, candidate groups for the double-difference integer ambiguity of the main frequency signal are determined as follows:

[0022] First, calculate the initial value of the double-difference integer ambiguity of the secondary frequency signal as follows:

[0023]

[0024] in, Represents the auxiliary frequency signal f Fu The initial value of the double-difference integer ambiguity. Represents the auxiliary frequency signal f Fu The difference between the observed inter-satellite distance and the satellite-to-Earth distance. Represents the auxiliary frequency signal f Fu Double-difference carrier phase observations, Auxiliary frequency signal f Fu The wavelength;

[0025] Secondly, using the initial value, candidate values ​​for the double-difference integer ambiguity of the auxiliary frequency signal are determined:

[0026] For satellite pairs i and j,

[0027]

[0028] Where i is the reference satellite, j is a satellite other than the reference satellite, j = 1, 2, ..., i-1, i+1, ..., k, E Length The band length of the error band for satellite pairs i and j is, according to one implementation method, constructed using the mean square error σ of l times the pseudorange difference observations of a single GNSS epoch. Specifically, it can be determined as follows:

[0029]

[0030] Where σ is the standard error of the pseudorange difference observations in a single epoch of GNSS. The wavelength of the auxiliary frequency signal is l = 2 to 5, and int(·) represents the integer operation.

[0031] The accuracy of the error bands of satellite pairs i and j can be increased by constructing the error σ of GNSS single-epoch pseudorange differential observations, where the pseudorange differential observations can be single-difference or double-difference observations.

[0032] In the above formula, Auxiliary frequency signal f Fu Candidate values ​​for double-difference integer ambiguity. The number of candidate values;

[0033] Secondly, using the following relational formula, of Determine the main frequency signal f Zhu Candidate values ​​for double-difference integer ambiguity:

[0034]

[0035] in:

[0036] 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 This refers to the bandwidth of the error band between satellites i and j. According to one implementation, the baseline length L formed between the base station b and the monitoring station m can be used. bm Construction. Determined according to one implementation method as follows:

[0037]

[0038] Using this implementation, due to the use of baseline length L bm This allows for better determination of bandwidth, increasing the accuracy of the satellite's error band construction for i and j.

[0039] Main frequency signal f Zhu Candidate values ​​for double-difference integer ambiguity.

[0040] v represents the number of candidate values;

[0041] Finally, the candidate values ​​for the double-difference integer ambiguity of the main frequency signal for all satellite pairs in a single epoch are expressed as follows:

[0042]

[0043] 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.

[0044] Then, in step S40, the candidate groups are subjected to a significance test using the double-difference carrier phase observation equation of the main frequency signal, and the candidate groups that pass the significance test are determined as the optimal groups.

[0045] According to one implementation, the optimal set of double-difference integer ambiguities of the main frequency signal is determined as follows:

[0046] First, the candidate groups of t for 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. 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:

[0047]

[0048] Written in matrix form:

[0049]

[0050] in, Subscript b indicates the base station, subscript m indicates the monitoring station, superscript i indicates the reference satellite with the largest elevation angle, and superscript j indicates a satellite other than the reference satellite, j = 1, 2, ..., i-1, i+1, ..., k. These are double-difference carrier phase observations. The wavelength of the main frequency signal. Candidate groups for the double-difference integer ambiguity of the main frequency signal; The difference between the observed inter-satellite distance and the satellite-to-Earth distance is given. and The cosine coefficient of the satellite-to-Earth distance direction. and Let m be the correction value for the three-dimensional coordinates of monitoring station m. The residuals of the double-difference carrier phase observations The constant term of the double-difference carrier phase observation equation at the main frequency;

[0051] 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:

[0052]

[0053] Where: k is the total number of observation satellites in a single epoch, and P is the weight matrix of the double-difference carrier phase observations in a single epoch;

[0054] From t candidate groups, t unit weight variance factors can be calculated, which can be represented by a set.

[0055] Next, sort the set {Ω} in ascending order to obtain the set {Ω} = {Ω1 Ω2 … Ω}. t Construct significance test values:

[0056]

[0057] 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.

[0058] Then, in step S50, the rounding group of the double-difference integer ambiguity of the main frequency signal is determined using the double-difference carrier phase observation equation of the main frequency signal.

[0059] According to one implementation, the rounding group of the double-difference integer ambiguity of the main frequency signal is determined as follows:

[0060] First, the optimal set of the determined double-difference integer ambiguities of the main frequency signal is substituted into the double-difference carrier phase observation equation of the main frequency signal. The least squares parameter indirect adjustment method is used to calculate the three-dimensional coordinate correction of monitoring station m. 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:

[0061]

[0062] 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:

[0063]

[0064] in, It is an integer set of double-difference integer ambiguities of the main frequency signal.

[0065] Finally, in step S60, the consistency between the optimal group and the rounding group is checked.

[0066] According to one implementation, the consistency between the optimal set and the rounding set of the double-difference integer ambiguity of the main frequency signal is checked as follows:

[0067] For the double-difference integer ambiguity of satellite pairs i and j in a single epoch, determine the optimal group. In the integer group Whether they are equal, j = 1, 2, ..., i-1, i+1, ..., k;

[0068] if If the GNSS single-epoch double-difference integer ambiguity resolution check is passed, it means that the satellite has successfully resolved the double-difference integer ambiguity for i and j.

[0069] if If the GNSS single-epoch double-difference integer ambiguity resolution check fails, it means that the satellite's double-difference integer ambiguity resolution for i and j has failed. The satellite's double-difference carrier phase observation equation for i and j is deleted, the double-difference carrier phase observation equation for the frequency signal is updated, and the GNSS single-epoch double-difference integer ambiguity resolution check is performed again.

[0070] The present invention provides a verification method for rapid GNSS single-epoch double-difference integer ambiguity resolution, which can be applied to construction tower cranes for various satellite positioning scenarios. In this case, the construction tower crane system may include a base station GNSS receiver and a monitoring station GNSS receiver. The monitoring station GNSS receiver may be installed on the tower arm or tower body of the construction tower crane. Using the GNSS single-epoch double-difference integer ambiguity resolution verification method of the present invention on the base station GNSS receiver and the monitoring station GNSS receiver can improve the reliability of the rapidly resolved double-difference integer ambiguity.

[0071] Figure 2 A schematic block diagram of a GNSS single-epoch double-difference integer ambiguity resolution and verification device according to one embodiment of the present invention is shown. Figure 2 As shown, a GNSS single-epoch double-difference integer ambiguity resolution and verification device according to an embodiment of the present invention includes:

[0072] The main frequency signal and auxiliary frequency signal determination unit 100 determines the main frequency signal and auxiliary frequency signal;

[0073] The double-difference carrier phase observation equation establishment unit 200 establishes 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.

[0074] Candidate group determination unit 300 uses the double-difference carrier phase observation equation of the auxiliary frequency signal to determine the candidate group of the double-difference integer ambiguity of the main frequency signal.

[0075] The optimal group determination unit 400 uses the double-difference carrier phase observation equation of the main frequency signal to perform a significance test on the candidate groups, and determines the candidate groups that pass the significance test as the optimal groups.

[0076] The integer group is determined by unit 500, using the double-difference carrier phase observation equation of the main frequency signal to determine the integer group of the double-difference integer ambiguity of the main frequency signal; and

[0077] The consistency check unit 600 checks the consistency between the optimal group and the rounding group.

[0078] The units described above perform the operations described in steps S10, S20, S30, S40, S50, and S60, respectively. 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.

[0079] 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 GNSS integer ambiguity resolution and verification method based on primary and secondary frequencies, the method comprising: Determine the primary frequency signal and the secondary frequency signal; Establish the double-difference carrier phase observation equations for the main frequency signal and the auxiliary frequency signal; By using the double-difference carrier phase observation equation of the auxiliary frequency signal, candidate groups of double-difference integer ambiguity of the main frequency signal are determined. The candidate groups are subjected to a significance test using the double-difference carrier phase observation equation of the main frequency signal, and the candidate groups that pass the significance test are determined as the optimal groups. Using the double-difference carrier phase observation equation of the main frequency signal, the integer group of the double-difference integer ambiguity of the main frequency signal is determined; and Check the consistency between the optimal group and the rounding group. The candidate groups for the double-difference integer ambiguity of the main frequency signal are determined as follows: First, calculate the initial value of the double-difference integer ambiguity of the secondary frequency signal as follows: in, Represents the auxiliary frequency signal f Fu The initial value of the double-difference integer ambiguity. Represents the auxiliary frequency signal f Fu The difference between the observed inter-satellite distance and the satellite-to-Earth distance. Represents the auxiliary frequency signal f Fu Double-difference carrier phase observations, Auxiliary frequency signal f Fu The wavelength; Secondly, using the initial value, candidate values ​​for the double-difference integer ambiguity of the auxiliary frequency signal are determined: For satellite pairs i and j, Where i is the reference satellite, j is a satellite other than the reference satellite, j = 1, 2, ..., i-1, i+1, ..., k, E Length The length of the error band for satellite pairs i and j. Auxiliary frequency signal f Fu Candidate values ​​for double-difference integer ambiguity. w is the number of candidate values; Secondly, using the following relational formula, of Determine the main frequency signal f Zhu Candidate values ​​for double-difference integer ambiguity: in: 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 secondary frequency signal. Auxiliary frequency signal f Fu Candidate values ​​for double-difference integer ambiguity, E Wide This refers to the bandwidth of the error band for satellite pairs i and j. Main frequency signal f Zhu Candidate values ​​for double-difference integer ambiguity. v represents the number of candidate values; Finally, the candidate values ​​for the double-difference integer ambiguity of the main frequency signal for all satellite pairs in a single epoch are expressed as follows: 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.

2. The method according to claim 1, characterized in that, The first frequency signal of the GPS, GLONASS, BDS, or Galileo system, or the 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.

3. The method according to claim 1, characterized in that, The optimal set of double-difference integer ambiguities for the main frequency signal is determined as follows: 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: Written in matrix form: in, Subscript b indicates the base station, subscript m indicates the monitoring station, superscript i indicates the reference satellite with the largest elevation angle, and superscript j indicates a satellite other than the reference satellite, j = 1, 2, ..., i-1, i+1, ..., k. These are double-difference carrier phase observations. The wavelength of the main frequency signal. Candidate groups for the double-difference integer ambiguity of the main frequency signal; The difference between the observed inter-satellite distance and the satellite-to-Earth distance is given. and The cosine coefficient of the satellite-to-Earth distance direction. and Let m be the correction value for the three-dimensional coordinates of monitoring station m. The residuals of the double-difference carrier phase observations, The constant term in the double-difference carrier phase observation equation of the main frequency signal; 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: Where: k is the total number of observation satellites in a single epoch, and P is the weight matrix of the double-difference carrier phase observations in a single epoch; From t candidate groups, t unit weight variance factors can be calculated, which can be represented by a set. Next, sort the elements in set {Ω} in ascending order to obtain set {Ω} = {Ω1Ω2…Ω}. t Construct significance test values: 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.

4. The method according to claim 3, characterized in that, The integer group of the double-difference integer ambiguity of the main frequency signal is determined as follows: 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: 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: in, It is an integer set of double-difference integer ambiguities of the main frequency signal.

5. The method according to claim 4, characterized in that, 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: For the double-difference integer ambiguity of satellite pairs i and j in a single epoch, determine the optimal group. In the integer group Whether they are equal, j = 1, 2, ..., i-1, i+1, ..., k; if If the GNSS single-epoch double-difference integer ambiguity resolution check is passed, it means that the satellite has successfully resolved the double-difference integer ambiguity for i and j. if If the GNSS single-epoch double-difference integer ambiguity resolution check fails, it means that the satellite failed to resolve the double-difference integer ambiguity for i and j.

6. The method according to claim 1, characterized in that, Determine E as follows Length : Where σ is the standard error of the pseudorange difference observations in a single epoch of GNSS. The wavelength of the auxiliary frequency signal is l = 2 to 5, and int(·) represents the integer operation; And determine E as follows Wide : Where: L bm The baseline length L between base station b and monitoring station m bm .

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