A method for detecting cycle slip of single-frequency global navigation satellite system observation data

Abstract

The application relates to a cycle slip detection method of single-frequency global navigation satellite system observation data, which comprises the following steps: collecting single-frequency global navigation satellite system observation data; calculating the phase increment of the carrier phase cumulative observation value of each satellite between adjacent epochs based on the carrier phase cumulative observation value of each satellite under an epoch sequence; performing time domain integration on the Doppler observation value of each satellite between adjacent epochs based on the Doppler observation value of each satellite under the epoch sequence to obtain a time domain integration result; subtracting the time domain integration result of the Doppler observation value of the current satellite between the current epoch and the previous epoch from the phase increment of the carrier phase cumulative observation value of the current satellite between the current epoch and the previous epoch to obtain a deviation detection quantity; setting a deviation detection quantity threshold value, and if the deviation detection quantity of the current satellite at the current epoch is greater than the deviation detection quantity threshold value, it is judged that the current satellite has a cycle slip at the current epoch.

Description

TECHNICAL FIELD

[0001] The present application relates to a cycle slip detection method for single-frequency global navigation satellite system (GNSS) observation data, and belongs to the technical field of satellite navigation and positioning. BACKGROUND

[0002] Global Navigation Satellite System (GNSS) carrier phase observations are the core data source for achieving centimeter to millimeter level high-precision positioning. However, in complex application scenarios (such as urban canyons, high-voltage tower perimeters, forest areas, etc.), factors such as signal obstruction, strong multipath interference, ionospheric scintillation, and receiver instantaneous loss of lock can cause discontinuous jumps in carrier phase integer counting (i.e., "cycle slip"). A single cycle slip event will directly introduce a positioning error equivalent to the carrier wavelength (for example, the wavelength of Beidou B1I is about 19 cm, and the error is as high as 0.19 m), and this error is cumulative and uncorrectable - if not detected and repaired in time, it will cause all subsequent epoch positioning results to fail.

[0003] It is worth noting that single-frequency receivers are significantly affected by ionospheric disturbances due to the lack of dual-frequency ionospheric delay correction capability. Real-world data shows that during periods of moderate ionospheric activity, the cycle slip occurrence rate of single-frequency devices can be 3-5 times that of dual-frequency devices. This poses a serious challenge to long-term high-precision positioning scenarios such as power inspection and geological disaster monitoring.

[0004] Current mainstream cycle slip detection methods have fundamental limitations when faced with single-frequency data:

[0005] Ionospheric residual method: relies on dual-frequency observations to construct ionosphere-independent combinations, which inherently excludes the possibility of single-frequency receivers, and cannot solve the pain points of low-cost devices that dominate the civilian market.

[0006] TurboEdit method (Ge et al., GPS Solutions, 2006): based on the Melbourne-Wübbena (MW) wide-lane combination, although it can effectively detect cycle slips, it strictly relies on dual-frequency observations to generate wide-lane ambiguities, and is completely ineffective in single-frequency systems.

[0007] Polynomial fitting method (Blewitt, Bulletin Géodésique, 1990): extrapolates and predicts current values from historical phase data, which is effective in static scenarios, but difficult to adapt to dynamic environments. Verification shows that when the receiver's acceleration exceeds 0.5 m / s², the cycle slip misjudgment rate exceeds 40%, and it cannot meet the needs of mobile power equipment inspection.

[0008] Traditional Doppler method: directly compare the rate of change of carrier phase with the instantaneous Doppler observation, which is suitable for single frequency data in principle. However, this method is extremely sensitive to observation noise: there is high frequency noise in the Doppler observation itself (typical noise level ± 0.5-1 cycle / s), and the integration error is amplified at low sampling rate (≤1 Hz), resulting in a detection noise as high as ±2 cycles. When the sampling rate is reduced to 1 Hz, the Doppler integration error can reach ±1.2 cycles, completely hiding the single cycle slip signal. SUMMARY

[0009] In order to solve the problems existing in the prior art, the present application provides a cycle slip detection method for single frequency global navigation satellite system observation data.

[0010] The technical scheme of the present application is as follows:

[0011] On the one hand, the present application provides a cycle slip detection method for single frequency global navigation satellite system observation data, comprising the following steps:

[0012] Collecting single frequency global navigation satellite system observation data, the observation data including carrier phase cumulative observation values of each satellite at a sequence of epochs and Doppler observation values;

[0013] Based on the carrier phase cumulative observation values of each satellite at a sequence of epochs, calculating the phase increment of the carrier phase cumulative observation values of each satellite between adjacent epochs;

[0014] Based on the Doppler observation values of each satellite at a sequence of epochs, performing time domain integration on the Doppler observation values of each satellite between adjacent epochs to obtain a time domain integration result;

[0015] Subtracting the phase increment of the carrier phase cumulative observation values of the current satellite between the current epoch and the previous epoch from the time domain integration result of the Doppler observation values of the current satellite between the current epoch and the previous epoch to obtain a bias detection quantity;

[0016] Setting a bias detection quantity threshold, if the bias detection quantity of the current satellite at the current epoch is greater than the bias detection quantity threshold, it is judged that there is a cycle slip of the current satellite at the current epoch.

[0017] Preferably, the phase increment calculation formula of the carrier phase cumulative observation values of each satellite between adjacent epochs is:

[0018]

[0019] Wherein: represents the carrier phase cumulative observation value of satellite at epoch to epoch ; and represents the phase increment of the carrier phase cumulative observation value of satellite the carrier phase accumulated observation value of the satellite at the epoch the carrier phase accumulated observation value of the satellite at the epoch the carrier phase accumulated observation value of the satellite

[0020] Preferably, the Doppler observation value of each satellite between adjacent epochs is time-domain integrated, and the specific steps are as follows:

[0021] setting a sampling time length , and dividing a plurality of time-domain intervals between the current epoch and the epoch according to the sampling time length;

[0022] time-domain integrating the Doppler observation value of each time-domain interval, and the specific formula is as follows:

[0023]

[0024] wherein: the Doppler observation value time-domain integration result of the satellite at the i-th time-domain interval; the starting time of the i-th time-domain interval; the Doppler observation value of the satellite at the i-th time-domain interval; the Doppler observation value of the satellite at the i-th time-domain interval ; and the integral variable;

[0025] adding the Doppler observation value time-domain integration results of all time-domain intervals to obtain the Doppler observation value time-domain integration result between the current epoch and the epoch .

[0026] Preferably, the calculated bias detection quantity is nearest-integer rounded.

[0027] In another aspect, the present application also provides a cycle slip detection system for single-frequency global navigation satellite system observation data, comprising a data acquisition module, a carrier phase increment calculation module, a Doppler observation value time-domain integration module, and a cycle slip judgment module.

[0028] The data acquisition module is used to acquire single-frequency global navigation satellite system observation data, and the observation data comprises carrier phase accumulated observation values of each satellite at a sequence of epochs and Doppler observation values;

[0029] The carrier phase increment calculation module is used to calculate phase increments of carrier phase accumulated observation values of each satellite between adjacent epochs based on the carrier phase accumulated observation values of each satellite at a sequence of epochs.​

[0030] The Doppler observation time domain integration module is configured to perform time domain integration on the Doppler observation values of each satellite between adjacent epochs based on the Doppler observation values of each satellite under a sequence of epochs, to obtain a time domain integration result.

[0031] The cycle slip judgment module is configured to subtract the phase increment of the carrier phase cumulative observation value of the current satellite between the current epoch and the previous epoch from the time domain integration result of the Doppler observation value of the current satellite between the current epoch and the previous epoch to obtain a bias detection quantity, set a bias detection quantity threshold, and if the bias detection quantity of the current satellite at the current epoch is greater than the bias detection quantity threshold, it is judged that the current satellite has a cycle slip at the current epoch.

[0032] Preferably, the phase increment calculation formula of the carrier phase cumulative observation value of each satellite between adjacent epochs is:

[0033]

[0034] Wherein: represents the carrier phase cumulative observation value of satellite at epoch to epoch ; represents the carrier phase cumulative observation value of satellite at epoch ; represents the carrier phase cumulative observation value of satellite at epoch .

[0035] Preferably, the time domain integration is performed on the Doppler observation values of each satellite between adjacent epochs, and the specific steps are as follows:

[0036] Set the sampling time length , and divide the time domain into multiple time domain intervals according to the sampling time length between the current epoch and epoch ;

[0037] For the Doppler observation value of each time domain interval, the time domain integration is performed as follows:

[0038]

[0039] Wherein: represents the Doppler observation value time domain integration result of satellite in the th time domain interval; represents the start time of the th time domain interval; represents the end time of the th time domain interval the Doppler observation value at the moment; denotes the integral variable;

[0040] adding the time-domain integral results of the Doppler observation values of all time-domain intervals to obtain the Doppler observation value time-domain integral result between the current epoch and the epoch .

[0041] Preferably, the calculated bias detection quantity is nearest-integer rounded.

[0042] In another aspect, the present application also provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the method as described in the present application when executing the program.

[0043] In another aspect, the present application also provides a computer readable storage medium, which stores a computer program, wherein the program is executable on a processor to implement the method as described in the present application.

[0044] The present application has the following beneficial effects:

[0045] 1. The present application performs time-domain integration on the Doppler observation value, can obtain high enough time resolution, ensures that the Doppler integral value can accurately reflect the real change trend of the carrier phase in a very short time, effectively suppresses the interference of observation noise on the bias detection quantity, and significantly improves the detection ability of the micro-cycle slip.

[0046] 2. The present application uses the consistent comparison between the high-precision time difference carrier phase change quantity between adjacent epochs and the short-time high-sampling-rate Doppler observation value integral, has the universal characteristics of signal frequency independence, is suitable for public service civilian signal frequency points, is widely used in low-cost single-frequency receivers, and can be effectively applied to the single-frequency data cycle slip detection of these mainstream civilian navigation frequency points. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The present application is a method flowchart. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0049] ​It should be understood that the step numbers used herein are only for the convenience of description and are not limited to the execution sequence of the steps.

[0050] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0051] The terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0052] The term "and / or" means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations.

[0053] Referring to Figure 1 A cycle slip detection method for single-frequency global navigation satellite system observation data, comprising the following steps:

[0054] Collecting single-frequency global navigation satellite system observation data, the observation data including carrier phase cumulative observation values of each satellite under a sequence of epochs and Doppler observation values;

[0055] Based on the carrier phase cumulative observation values of each satellite under the sequence of epochs, calculating the phase increment of the carrier phase cumulative observation values of each satellite between adjacent epochs;

[0056] Based on the Doppler observation values of each satellite under the sequence of epochs, performing time-domain integration on the Doppler observation values of each satellite between adjacent epochs to obtain a time-domain integration result;

[0057] Subtracting the phase increment of the carrier phase cumulative observation values of the current satellite between the current epoch and the previous epoch from the time-domain integration result of the Doppler observation values of the current satellite between the current epoch and the previous epoch to obtain a deviation detection quantity;

[0058] Setting a deviation detection quantity threshold, if the deviation detection quantity of the current satellite at the current epoch is greater than the deviation detection quantity threshold, it is judged that there is a cycle slip of the current satellite at the current epoch.

[0059] In some embodiments, the phase increment calculation formula of the carrier phase cumulative observation values of each satellite between adjacent epochs is:

[0060]

[0061] Wherein: represents the satellite At epoch To epoch Phase increment of carrier phase cumulative observations (essentially true phase increment including cycle slips) from epoch To epoch To epoch Carrier phase cumulative observations of satellite At epoch At epoch Carrier phase cumulative observations of satellite At epoch At epoch

[0062] In some embodiments, the Doppler observations of each satellite between adjacent epochs are integrated in time domain, and the specific steps are as follows:

[0063] Set the sampling time length , and divide the time domain into multiple time intervals between the current epoch and epoch according to the sampling time length;

[0064] Integrate the Doppler observations of each time interval in time domain, and the specific formula is as follows:

[0065]

[0066] Wherein: represents the Doppler observation time domain integration result of satellite in the th time interval; represents the starting time of the th time interval; represents the Doppler observation of satellite at the th time interval ; represents the integral variable;

[0067] Add the time domain integration results of the Doppler observations of all time intervals to obtain the Doppler observation time domain integration result between the current epoch and epoch .

[0068] In a specific embodiment, the sampling time length is in the range of seconds. A too long sampling interval (>1 second) will significantly increase the cumulative error of Doppler integration value, making it difficult to effectively capture the subtle phase change difference caused by a small cycle slip, thereby reducing the sensitivity and reliability of cycle slip detection.

[0069] In one specific embodiment, the sampling time length is in the range of [0.05, 0.2] seconds.

[0070] In some embodiments, the calculated bias detection quantity is nearest-integer rounded. The rounding method is critical to achieve the conversion of the bias detection quantity from a continuous value to the nearest integer with no bias and minimized rounding error. In the context of cycle slip detection, the theoretical value of the bias detection quantity should be an integer when there is no cycle slip, and in actual calculation, it is a decimal value close to the integer due to observation noise and residual error. By rounding down after adding 0.5 to the input value, it is ensured that when the decimal part is less than 0.5, the rounding is to the direction of the smaller absolute value, and when the decimal part is greater than or equal to 0.5, the rounding is to the direction of the larger absolute value, thereby achieving the optimal approximation of the true integer value.

[0071] Compared with simple truncation rounding or upward rounding, this rounding strategy can effectively avoid the risk of misjudgment or missed judgment of cycle slip caused by systematic rounding bias, especially in the critical region where the decimal part of the bias detection quantity is close to ±0.5. This feature is crucial for detecting small cycle slips (especially single cycle slips) with high reliability, because judgment errors near the critical region will directly affect the accuracy of detection. The use of this nearest-integer rounding method significantly improves the robustness and confidence of cycle slip detection in the presence of observation noise.

[0072] In one specific embodiment, the bias detection quantity threshold is set to 0.15 cycles. This specific threshold of 0.15 cycles is determined based on statistical analysis of the noise characteristics of single-frequency BDS / GNSS observation data (particularly carrier phase and Doppler observation values) in the power scenario, cycle slip detection sensitivity requirements, and false alarm rate control. On the one hand, the threshold is significantly larger than the carrier phase difference observation noise level (usually in the order of a few cycles to 0.1 cycles), which can effectively suppress normal fluctuations caused by random observation noise and residual multipath effects from being misjudged as cycle slips (i.e., control the false alarm rate); on the other hand, 0.15 cycles is significantly smaller than the minimum cycle slip to be detected (1 cycle), ensuring that the method has high sensitivity for detecting single cycle slips (i.e., the smallest possible integer cycle slip). The preferred threshold of 0.15 cycles provides an optimal balance between detection reliability and sensitivity in typical power application environments (e.g., with some degree of multipath and ionospheric scintillation interference).

[0073] The method is particularly suitable for processing single-frequency observation data from the following global navigation satellite system (GNSS) frequencies: B1I frequency of the BeiDou Satellite Navigation System (BDS), L1 frequency of the Global Positioning System (GPS), and E1 frequency of the Galileo Satellite Navigation System (Galileo).

[0074] In some embodiments, a cycle slip detection system for single-frequency global navigation satellite system observation data is provided, comprising a data acquisition module, a carrier phase increment calculation module, a Doppler observation value time domain integration module, and a cycle slip judgment module.

[0075] The data acquisition module is configured to acquire single-frequency global navigation satellite system observation data, wherein the observation data comprises carrier phase cumulative observation values of each satellite under a sequence of epochs and Doppler observation values of each satellite under the sequence of epochs.

[0076] The carrier phase increment calculation module is configured to calculate phase increments of carrier phase cumulative observation values of each satellite between adjacent epochs based on the carrier phase cumulative observation values of each satellite under the sequence of epochs.

[0077] The Doppler observation value time domain integration module is configured to perform time domain integration on Doppler observation values of each satellite between adjacent epochs based on the Doppler observation values of each satellite under the sequence of epochs to obtain time domain integration results.

[0078] The cycle slip judgment module is configured to subtract the time domain integration results of the Doppler observation values of the current satellite between the current epoch and the previous epoch from the phase increments of the carrier phase cumulative observation values of the current satellite between the current epoch and the previous epoch to obtain a deviation detection quantity, set a deviation detection quantity threshold, and if the deviation detection quantity of the current satellite at the current epoch is greater than the deviation detection quantity threshold, it is determined that there is a cycle slip of the current satellite at the current epoch.

[0079] In some embodiments, an electronic device is also provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of the embodiments of the present application when executing the program.

[0080] In some embodiments, a computer readable storage medium having a computer program stored thereon is also provided, wherein the program is executable on a processor to implement the method according to any one of the embodiments of the present application.

[0081] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects. "At least one of the following" and the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, and c can be single or multiple.

[0082] Those skilled in the art can clearly understand that the units and algorithm steps described in the embodiments disclosed herein can be realized by electronic hardware, computer software and a combination of electronic hardware and computer software. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0083] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0084] In several embodiments provided in the present application, any function realized in the form of a software function unit and sold or used as an independent product can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the parts that make contributions to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory; hereinafter referred to as: ROM), a random access memory (Random Access Memory; hereinafter referred to as: RAM), a magnetic disk or an optical disk and various program code storage media.

[0085] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation based on the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A cycle slip detection method for single-frequency global navigation satellite system (GNSS) observation data, characterized in that, The method comprises the following steps: Collecting single-frequency global navigation satellite system observation data, the observation data comprising carrier phase cumulative observation values of each satellite under a sequence of epochs and Doppler observation values; Based on the carrier phase cumulative observation values of each satellite under the sequence of epochs, calculating phase increments of the carrier phase cumulative observation values of each satellite between adjacent epochs; Based on the Doppler observation values of each satellite under the sequence of epochs, performing time-domain integration on the Doppler observation values of each satellite between adjacent epochs to obtain time-domain integration results; Subtracting the phase increment of the carrier phase cumulative observation values of the current satellite between the current epoch and the previous epoch from the time-domain integration result of the Doppler observation values of the current satellite between the current epoch and the previous epoch to obtain a deviation detection quantity; Setting a deviation detection quantity threshold, and if the deviation detection quantity of the current satellite at the current epoch is greater than the deviation detection quantity threshold, it is determined that there is a cycle slip of the current satellite at the current epoch.

2. The cycle slip detection method of single-frequency global navigation satellite system observation data according to claim 1, characterized in that, The formula for calculating the phase increment of the carrier phase cumulative observation values of each satellite between adjacent epochs is: wherein: denotes the satellite at epoch to epoch the phase increment of the carrier phase accumulated observations; denotes the satellite at epoch the carrier phase accumulated observations; denotes the satellite at epoch the carrier phase accumulated observations.

3. The method of cycle slip detection for single-frequency global navigation satellite system observations according to claim 1, characterized in that, The specific steps for performing time-domain integration on the Doppler observation values of each satellite between adjacent epochs are: Setting a sampling time length , dividing a plurality of time domain intervals between the current epoch and the epoch according to the sampling time length; For each time-domain interval, the time-domain integration of the Doppler observation values is performed as shown in the following formula: in: Indicates the first Satellites in each time domain interval Time-domain integral results of Doppler observations; Indicates the first The start time of each time domain interval; Indicates the first time domain intervals Satellite at all times Doppler observations; Represents the integral variable; The time domain integration results of Doppler observations of all time domain intervals are added to obtain the current epoch Doppler observations of all time domain intervals are added to obtain the current epoch Doppler observations of all time domain intervals are added to obtain the current epoch 4. The method of cycle slip detection for single-frequency global navigation satellite system observations according to claim 1, characterized in that, The nearest-integer rounding is performed on the calculated deviation detection quantity.

5. A cycle slip detection system for single-frequency global navigation satellite system observation data, characterized in that, The method comprises a data collection module, a carrier phase increment calculation module, a Doppler observation value time-domain integration module, and a cycle slip judgment module; The data collection module is configured to collect single-frequency global navigation satellite system observation data, the observation data comprising carrier phase cumulative observation values of each satellite under a sequence of epochs and Doppler observation values; The carrier phase increment calculation module is configured to calculate phase increments of the carrier phase cumulative observation values of each satellite between adjacent epochs based on the carrier phase cumulative observation values of each satellite under the sequence of epochs; The Doppler observation value time-domain integration module is configured to perform time-domain integration on the Doppler observation values of each satellite between adjacent epochs based on the Doppler observation values of each satellite under the sequence of epochs to obtain time-domain integration results; The cycle slip judgment module is configured to subtract the phase increment of the carrier phase cumulative observation values of the current satellite between the current epoch and the previous epoch from the time-domain integration result of the Doppler observation values of the current satellite between the current epoch and the previous epoch to obtain a deviation detection quantity; A deviation detection quantity threshold is set, and if the deviation detection quantity of the current satellite at the current epoch is greater than the deviation detection quantity threshold, it is determined that there is a cycle slip of the current satellite at the current epoch.

6. The cycle slip detection system for single-frequency global navigation satellite system observations according to claim 5, wherein, The formula for calculating the phase increment of the carrier phase cumulative observation values of each satellite between adjacent epochs is: wherein: denotes the satellite at epoch denotes the satellite at epoch denotes the phase increment of the carrier phase cumulative observation value of the satellite at epoch denotes the carrier phase cumulative observation value of the satellite at epoch denotes the carrier phase cumulative observation value of the satellite at epoch 7. The cycle slip detection system for single-frequency global navigation satellite system observations of claim 5, wherein, The specific steps for performing time-domain integration on the Doppler observation values of each satellite between adjacent epochs are: Setting a sampling time length , according to the sampling time length in the current epoch and dividing a plurality of time domain intervals between the epoch ; For each time-domain interval, the time-domain integration of the Doppler observation values is performed as shown in the following formula: wherein: denotes the Doppler observation value of the satellite at the time interval ; denotes the time-domain integral result of the Doppler observation value of the satellite at the time interval ; denotes the starting time of the time interval ; denotes the Doppler observation value of the satellite at the time interval ; denotes the Doppler observation value of the satellite at the time interval ; denotes the integral variable; The time domain integration results of Doppler observations of all time domain intervals are added to obtain the current epoch Doppler observation time domain integration results between epochs ​ 8. The cycle slip detection system of single-frequency global navigation satellite system observation data according to claim 5, wherein, The nearest-integer rounding is performed on the calculated deviation detection quantity.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the method of any one of claims 1 to 4.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method of any one of claims 1 to 4.

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