GNSS single-frequency real-time cycle slip detection and repair method, electronic device and storage medium

Abstract

The application discloses a GNSS single-frequency real-time cycle slip detection and repair method, electronic equipment and a storage medium, and relates to the technical field of GNSS positioning, in particular to a GNSS single-frequency real-time cycle slip detection and repair method, electronic equipment and a storage medium. The method comprises the following steps: obtaining an inter-epoch position change based on the relationship between GNSS Doppler observation values and GNSS carrier phase observation values, obtaining an inter-epoch single-difference equation by subtracting the carrier phase observation values of adjacent time points, and constructing satellite sample statistics; generating a cluster according to the density around each sample point in the satellite sample statistics and a set threshold; obtaining a position change by using the observation values corresponding to the satellite samples in the cluster through a time-difference carrier phase method; calculating a new satellite position based on the position change; calculating an omc value based on the new satellite position; judging whether a cycle slip occurs based on the omc value, and repairing the cycle slip. The application realizes high-precision positioning based on GNSS observation data of a smart phone by collecting GNSS observation data of the smart phone itself, fusing Doppler velocity and inter-epoch difference observation values of carrier phase, and constructing clustered satellite sample statistics.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation positioning, in particular to a GNSS single-frequency real-time cycle slip detection and repair method suitable for smart phones, an electronic device and a storage medium. BACKGROUND

[0002] At present, most users of CORS systems are surveying and mapping units and engineering construction units. In daily use, they all use professional surveying RTK equipment terminals to obtain centimeter-level navigation positioning results. However, professional RTK equipment terminals are expensive and inconvenient to carry, and the data transmission is complex for professional applications such as daily land law enforcement and natural resource investigation. If positioning data is collected directly through a mobile phone or a tablet, it is difficult to track the carrier phase with a phase-locked loop under high dynamic conditions such as vehicle navigation due to the limitations of the hardware conditions, and the phase-locked loop is easily lost, which leads to a large number of cycle slips in the observation values. If the cycle slips are not accurately detected and repaired, the ambiguity will be affected and the positioning result will be affected. Therefore, real-time cycle slip detection and repair is the primary prerequisite for high-precision positioning.

[0003] The prior art has carried out a large number of studies on single-frequency cycle slip detection. The main methods are mainly divided into three categories: the first category of method regards the cycle slip as a gross error, and then determines the satellite with abnormal residual as a cycle slip satellite based on least squares. This method is mainly suitable for a small number of cycle slips, but under complex high dynamic conditions, a large number of cycle slips are easily generated. Since the least squares has good error balancing properties, it is easily affected by gross errors. Therefore, when there are a large number of cycle slip satellites, the success rate of this method decreases and even misjudgments occur. The second category is to use the smoothness of the sequence. When a cycle slip occurs, this property is destroyed, which is used to detect cycle slips. However, this method requires a certain amount of historical data, which is not conducive to real-time mode, and is easily affected by the change of the motion state of the receiver, and is not suitable for high dynamic scenes. The third category is to use the frequency shift value of the Doppler measurement value which is independent of the integer cycle counter to detect cycle slips. However, due to the limitation of the sampling frequency, misjudgments easily occur under high dynamic conditions. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a GNSS single-frequency real-time cycle slip detection and repair method suitable for smart phones, an electronic device and a storage medium, so that the repaired smart phone GNSS observation data can also obtain good positioning accuracy through connection to CORS.

[0005] To achieve the above purpose, the technical scheme of the present application is as follows:

[0006] In a first aspect, the present application provides a GNSS single-frequency real-time cycle slip detection and repair method suitable for smart phones, characterized in that it comprises:

[0007] acquiring GNSS carrier phase observations and GNSS Doppler observations;

[0008] obtaining an inter-epoch position change based on a relationship between the GNSS Doppler observations and the GNSS carrier phase observations, differencing GNSS carrier phase observations at adjacent times to obtain an inter-epoch single difference equation, and constructing satellite sample statistics;

[0009] generating a cluster based on a density around each satellite sample point in the satellite sample statistics and a set threshold value;

[0010] obtaining a position change by time-differenced carrier phase using GNSS carrier phase observations corresponding to satellite samples in the cluster;

[0011] calculating a new satellite position based on the position change and calculating an omc value based on the new satellite position;

[0012] judging whether a cycle slip occurs based on the omc value and repairing the cycle slip.

[0013] Optionally, the omc value is:

[0014]

[0015] is a GNSS carrier phase observation, and D is a distance between the new satellite position and the receiver.

[0016] The GNSS carrier phase observation is calculated by a GNSS carrier phase observation equation as follows:

[0017]

[0018] where λ is a wavelength, is a carrier phase observation in cycles, d is a geometric distance between a satellite and a receiver, c is a speed of light, dt u is a receiver clock error, dt s is a satellite clock error, N is an integer ambiguity, d ion is an ionospheric delay, d trop is a tropospheric delay, B r is an uncalibrated phase delay at a receiver end, B s is an uncalibrated phase delay at a satellite end, ε L is a carrier phase observation noise and multipath effect and other un-modeled errors.

[0019] Optionally, the inter-epoch position change is:

[0020]

[0021] In the formula, is an unknown change vector, is a velocity vector of the previous epoch, is a velocity vector of the current epoch, t k is a time of the current epoch, t k-1 is a time of the previous epoch.

[0022] Optionally, the inter-epoch single difference equation is:

[0023]

[0024] In the formula, λ is a wavelength, is a difference value of GNSS carrier phase observations between two epochs, δd is a difference value of geometric distances between satellites and receivers between two epochs, c is a speed of light, δdt u is a difference value of receiver clock errors between two epochs, δdt s is a difference value of satellite clock errors between two epochs, ΔN is a difference value of integer ambiguities between two epochs, δd ion is a difference value of ionospheric delays between two epochs, δd trop is a difference value of tropospheric delays between two epochs, is a difference value of carrier phase observation noises and multipath effects and other un-modeled errors between two epochs.

[0025] Optionally, the satellite sample statistical quantity content is a sum of receiver clock error change, cycle slip and noise:

[0026]

[0027] In the formula, ν is a satellite sample statistical quantity.

[0028] Optionally, the generating a cluster according to a density around each satellite sample point in the satellite sample statistical quantity and a set threshold value comprises:

[0029] The difference between the ν value of each satellite in the satellite sample statistical quantity and the ν value of other satellites is calculated, and N sets are formed assuming that there are N satellites; N is a positive integer;

[0030] The density is represented by the number of samples within a set threshold value range of the region radius, the number of elements within the boundary of each set region is counted, and the set with the largest number is taken as the generated cluster.

[0031] Optionally, the judging whether a cycle slip occurs based on the omc value and repairing the cycle slip comprises:

[0032] The omc value is compared with a preset threshold value, and if it is greater than the threshold value, it is considered that a cycle slip occurs in the satellite;

[0033] For the satellite with cycle slip, if the set condition is met, cycle slip repair is performed, otherwise the satellite with cycle slip does not participate in subsequent calculation.

[0034] In a second aspect, the present application provides an electronic device comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete the communication among each other through the communication bus.

[0035] The memory is used for storing a computer program.

[0036] The processor is used for executing the program stored on the memory, and realizes the steps of the GNSS single-frequency real-time cycle slip detection and repair method for smart phones according to any one of the above.

[0037] In a third aspect, the present application provides a computer readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to realize the steps of the GNSS single-frequency real-time cycle slip detection and repair method for smart phones according to any one of the above.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] The present application realizes high-precision positioning based on GNSS observation data of smart phones by collecting GNSS observation data of smart phones, fusing Doppler velocity and carrier phase epoch difference observation values to construct clustered satellite sample statistics, and then generating clusters according to the density of sample distribution, and further detecting and repairing cycle slip by using accurate position increments. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The flowchart of the GNSS single-frequency real-time cycle slip detection and repair method for smart phones according to the present application embodiment 1 is provided.

[0041] Figure 2 The composition schematic diagram of the electronic device according to the present application embodiment 2 is provided. DETAILED DESCRIPTION

[0042] The technical solutions of the present application will be further described below in combination with the drawings and embodiments.

[0043] Embodiment 1:

[0044] In order to solve the problem that the existing smart phones are prone to cycle slip in high dynamic scenes and affect the positioning accuracy, the present embodiment provides a GNSS single-frequency real-time cycle slip detection and repair method for smart phones, as shown in Figure 1 The method mainly includes the following steps:

[0045] 110, acquiring GNSS carrier phase observation values and GNSS Doppler observation values;

[0046] 120、Based on the relationship between the GNSS Doppler observation value and the GNSS carrier phase observation value, the interepoch position change quantity is obtained, and the GNSS carrier phase observation values at adjacent time points are subtracted to obtain an interepoch single-difference equation, so as to construct a satellite sample statistical quantity;

[0047] In this step, the Doppler velocity measurement and the interepoch difference observation value of the carrier phase are fused, and the accuracy of the satellite sample statistical quantity is improved.

[0048] 130、Generating a cluster according to the density around each satellite sample point in the satellite sample statistical quantity and a set threshold value;

[0049] In this step, the density clustering algorithm is adopted, and a large number of cycle slip situations that may occur in a high dynamic scene are effectively processed.

[0050] 140、Using the GNSS carrier phase observation value corresponding to the satellite sample in the cluster, a position change quantity is obtained through time-difference carrier phase resolution (referred to as TDCP resolution);

[0051] In this step, the accurate position change quantity is obtained by using the time-difference carrier phase resolution, and the precision of cycle slip detection and repair is improved

[0052] 150、According to the position change quantity, a new satellite position (the new satellite position can be obtained by adding the position increment to the original satellite position) is calculated, and an omc value is calculated based on the new satellite position;

[0053] 160、Based on the omc value, it is judged whether the satellite has cycle slip, and the cycle slip is repaired.

[0054] As can be seen, by using the collected GNSS observation data of the intelligent mobile phone, the Doppler velocity measurement and the interepoch difference observation value of the carrier phase are fused to construct the clustered satellite sample statistical quantity, then the cluster is generated according to the density of the sample distribution, and then the accurate position increment is further used to detect and repair the cycle slip, so as to realize the high-precision positioning based on the GNSS observation data of the intelligent mobile phone.

[0055] In a specific implementation, the omc value is:

[0056]

[0057] is the GNSS carrier phase observation value, and D is the distance between the new satellite position and the receiver.

[0058]

[0059] In the formula, (X r ,Y r ,Zr ) is the three-dimensional Cartesian coordinate of the receiver position, s s s ) is the three-dimensional Cartesian coordinate of the new satellite position.

[0060] In a specific embodiment, the GNSS carrier phase observation is calculated by the GNSS carrier phase observation equation as follows:

[0061]

[0062] where λ is the wavelength, is the carrier phase observation in cycles, d is the geometric distance between the satellite and the receiver, c is the speed of light, dt u is the receiver clock error, dt s is the satellite clock error, N is the integer ambiguity, d ion is the ionospheric delay, d trop is the tropospheric delay, B r is the uncalibrated phase delay at the receiver end, B s is the uncalibrated phase delay at the satellite end, ε L is the noise and multipath effect of the carrier phase observation and other un-modeled errors.

[0063] The inter-epoch position change is

[0064]

[0065] where is the unknown change vector, is the velocity vector of the previous epoch, is the velocity vector of the current epoch, t k is the time of the current epoch, t k-1 is the time of the previous epoch.

[0066] The single-difference equation between epochs is

[0067]

[0068] where λ is the wavelength, is the difference of the carrier phase observation between two epochs, δd is the difference of the geometric distance between the satellite and the receiver between two epochs, c is the speed of light, δdt u is the difference of the receiver clock error between two epochs, δdt s is the difference of the satellite clock error between two epochs, ΔN is the difference of the integer ambiguity between two epochs, δd ion is the difference of the ionospheric delay between two epochs, δd trop is the difference of the tropospheric delay between two epochs,​​ is the difference of the noise and multipath effect between two epochs.

[0069] The satellite sample statistical quantity content is the sum of the receiver clock difference variation, cycle slip and noise.

[0070]

[0071] In the formula, v is the satellite sample statistical quantity, and other variables are the same as the above formula.

[0072] In this way, by constructing the satellite sample statistical quantity considering various factors, a reliable data basis is provided for subsequent density clustering and cycle slip detection, and the accuracy and sensitivity of cycle slip detection are effectively improved.

[0073] In a specific embodiment, the step 130 comprises:

[0074] The difference between the v value of each satellite in the satellite sample statistical quantity and the v value of other satellites is calculated, and assuming that there are N satellites, N sets can be formed:

[0075] E i = {d | d = |v j -v i |, j = 1, 2,..., N, j ≠ i} i = 1, 2,..., N

[0076] In the formula, E i is the difference value set of the ith satellite, d is the difference value between two satellites, v j is the sample value of the jth satellite, and v i is the sample value of the ith satellite.

[0077] The density is represented by the number of samples in the set within the set radius threshold range, the number of elements within the boundary of each set is counted, and the set with the largest number of elements is taken as the generated cluster.

[0078] Specifically, in this embodiment, the region radius threshold is empirically set to 0.05 m, and the minimum number of elements in the region must be no less than 8, if not, the region radius is adjusted appropriately. The number of elements within the boundary of each set E i is counted, and the set with the largest number of elements is recorded as E max The difference between the v value of each satellite and the v value of other satellites is calculated for each satellite, and assuming that there are N satellites, N sets can be formed: the set is the generated cluster.

[0079] In this way, the above density clustering algorithm can effectively handle a large number of cycle slips that may occur in high dynamic scenarios, accurately filter out satellites that may have cycle slips by identifying high-density regions, and improve the robustness and accuracy of cycle slip detection.

[0080] In a specific embodiment, step 160 comprises:

[0081] When omc>0.05m, it is considered that cycle slip occurs for the satellite;

[0082] For the satellite with cycle slip, if |omc / λ-ΔN|<0.15, cycle slip is repaired, otherwise the satellite does not participate in subsequent calculation.

[0083] In this way, by setting a reasonable threshold, the method can effectively identify cycle slip, accurately correct the repairable cycle slip, and eliminate the observation values that cannot be reliably repaired, thereby significantly improving the quality of GNSS observation data and the accuracy of subsequent positioning.

[0084] Embodiment 2:

[0085] The embodiment provides an electronic device, referring to Figure 2 as shown, comprising a processor 111, a communication interface 112, a memory 113 and a communication bus 114, wherein the processor 111, the communication interface 112 and the memory 113 complete mutual communication through the communication bus 114; the memory 113 is used for storing a computer program; the processor 111 is used for executing the program stored on the memory 113, and realizes the steps of the GNSS single-frequency real-time cycle slip detection and repair method suitable for a smart phone provided in embodiment 1.

[0086] Embodiment 3:

[0087] The embodiment of the application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the steps of the GNSS single-frequency real-time cycle slip detection and repair method suitable for a smart phone provided in any one of the preceding method embodiments.

[0088] It should be noted that in this paper, relationship terms such as "first" and "second" 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 the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a…" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0089] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the essence of the present application should be covered within the protection scope of the present application.

Claims

1. A GNSS single-frequency real-time cycle-slip detection and repair method suitable for a smartphone, characterized in that, The method comprises: acquiring GNSS carrier phase observations and GNSS Doppler observations; obtaining an inter-epoch position change based on a relationship between the GNSS Doppler observations and the GNSS carrier phase observations, and obtaining an inter-epoch single-difference equation by differencing GNSS carrier phase observations at adjacent time instants, and constructing satellite sample statistics; generating a cluster according to a density around each satellite sample point in the satellite sample statistics and a set threshold value; obtaining a position change by time-difference carrier phase using GNSS carrier phase observations corresponding to satellite samples in the cluster; calculating a new satellite position based on the position change, and calculating an omc value based on the new satellite position; judging whether a cycle slip occurs in the satellite based on the omc value, and repairing the cycle slip; the omc value is: D is the distance between the new position of the satellite and the receiver; the inter-epoch position change is: wherein is the unknown change vector, is the velocity vector of the previous epoch, is the velocity vector of the current epoch, t k is the time of the current epoch, t k-1 is the time of the previous epoch; the generating a cluster according to a density around each satellite sample point in the satellite sample statistics and a set threshold value comprises: calculating a difference between a value of each satellite in the satellite sample statistics and values of other satellites, assuming that there are N satellites, and then N sets are formed; N is a positive integer; representing the density by a number of samples within a set radius threshold range, counting a number of elements within a boundary of each set, and taking a set with the largest number as a generated cluster. 2.The GNSS single-frequency cycle slip detection and repair method for smartphones of claim 1, wherein, the GNSS carrier phase observations are calculated by a GNSS carrier phase observation equation as follows: where λ is the wavelength, is the carrier phase observation in cycles, d is the geometric range between the satellite and receiver, c is the speed of light, dt u is the receiver clock error, dt s is the satellite clock error, N is the integer ambiguity, d ion is the ionospheric delay, d trop is the tropospheric delay, B r is the uncalibrated phase delay at the receiver end, B s is the uncalibrated phase delay at the satellite end, ε L is the carrier phase observation noise and multipath effects and other unmodelled errors. 3.The GNSS single-frequency cycle slip detection and repair method for smartphones of claim 2, wherein, the inter-epoch single-difference equation is: where λ is the wavelength, is the difference of GNSS carrier phase observations between two epochs, δd is the difference of geometric distance between satellite and receiver between two epochs, c is the speed of light, δdt u is the difference of receiver clock error between two epochs, δdt s is the difference of satellite clock error between two epochs, ΔN is the difference of integer ambiguity between two epochs, δd ion is the difference of ionosphere delay between two epochs, δd trop is the difference of troposphere delay between two epochs, is the difference of carrier phase observation noise and multipath effect and other un-modeled errors between two epochs.

4. The GNSS single-frequency cycle slip detection and repair method for smartphones of claim 3, wherein, the satellite sample statistics content is a sum of a receiver clock change, a cycle slip and noise: wherein, v is a satellite sample statistics. 5.The GNSS single-frequency cycle slip detection and repair method for smartphones of claim 1, wherein, the judging whether a cycle slip occurs in the satellite based on the omc value, and repairing the cycle slip comprises: comparing the omc value with a preset threshold value, and considering that a cycle slip occurs in the satellite if the omc value is greater than the threshold value; for the satellite with the cycle slip, if a set condition is met, the cycle slip is repaired, otherwise the satellite with the cycle slip does not participate in subsequent calculation.

6. An electronic device, comprising: The device comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete mutual communication through the communication bus; the memory is used for storing a computer program; the processor is used for executing the program stored on the memory, and realizes steps of the GNSS single-frequency real-time cycle slip detection and repair method for a smart phone according to any one of claims 1-5.

7. A computer-readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to realize steps of the provided GNSS single-frequency real-time cycle slip detection and repair method for a smart phone according to any one of claims 1-5.

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