Adaptive frequency modulation cycle slip detection method and system considering ionospheric changes and storage medium

Abstract

The application provides an adaptive frequency modulation cycle slip detection method, system and storage medium considering ionospheric changes, the method comprising: step 1, determining the frequency and frequency number of available carrier phase observations of each satellite at the epoch; step 2, adaptively adapting the cycle slip detection method of three-frequency, double-frequency and single-frequency according to the available frequency and frequency number; step 3, in the case of adapting three-frequency, the epoch-differential three-frequency pseudorange / carrier phase ionosphere-free combination cycle slip detection quantity and threshold value are established, and three-frequency cycle slip detection is carried out; step 4, in the case of adapting double-frequency, the epoch-differential double-frequency double-difference carrier phase ionosphere-free combination cycle slip detection quantity and threshold value are established, and double-frequency cycle slip detection is carried out; step 5, in the case of adapting single-frequency, the twice epoch-differential single-frequency double-difference carrier phase weak ionosphere combination cycle slip detection quantity and threshold value are established, and single-frequency cycle slip detection is carried out; step 6, based on the cycle slip detection result, cycle slip marking is carried out, and cycle slip detection of the next epoch is started.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation and positioning technology, specifically relating to an adaptive frequency modulation cycle slip detection method, system, and storage medium that takes into account ionospheric changes. Background Technology

[0002] my country's BeiDou-based Global Navigation Satellite System (GNSS) not only possesses continuous, high-precision, all-weather monitoring capabilities, but can also directly acquire three-dimensional vector deformation of landslide surfaces, making it one of the most important means of landslide monitoring and early warning. Landslide disasters often occur in complex environments such as mountainous and hilly areas, which can easily affect the quality of BeiDou / GNSS data preprocessing and the accuracy of monitoring and positioning.

[0003] Cycle slips are a phenomenon where temporary interruptions in satellite signals, caused by factors such as obstruction, receiver malfunction, and low signal-to-noise ratio, result in abrupt changes in the integer count of carrier phase observations. The remaining portion of the count, even if less than a full cycle, remains correct. Missed or excessive cycle slips affect the accuracy and timing of multi-epoch ambiguity resolution, severely impacting positioning reliability and accuracy. Therefore, accurate detection and elimination of cycle slips are crucial for high-precision positioning. Currently, GNSS receivers can receive multi-frequency observation data. Using multi-frequency data can create combined observations with longer wavelengths, lower noise, and less ionospheric interference, effectively improving the accuracy of cycle slip detection and correction. However, cycle slips occur more frequently in complex observation environments, especially under adverse conditions such as vegetation obstruction, earthquakes, heavy rainfall, and ionospheric disturbances, making reliable detection even more difficult. This is mainly because under these conditions, receivers only obtain observation data for incomplete frequencies, making it impossible to detect cycle slips using fixed three-frequency or two-frequency methods, leading to missed cycle slips. Secondly, the occurrence of landslides induced by earthquakes will trigger short-term anomalies in the ionosphere, which urgently requires reliable cycle slip detection methods in an active ionospheric environment. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an adaptive frequency-modulated cycle slip detection method, system, and storage medium that takes into account ionospheric changes. It can adaptively select three-frequency, dual-frequency, and single-frequency cycle slip detection methods based on the frequency number of the received raw observation data, thereby achieving reliable detection of cycle slips under active ionospheric conditions and at different frequency numbers.

[0005] To achieve the above objectives, the present invention adopts the following solution:

[0006] <Method>

[0007] This invention provides an adaptive frequency modulation cycle slip detection method that takes into account ionospheric changes, comprising the following steps:

[0008] Step 1: Acquire carrier phase observation data, and determine the available carrier phase observation frequency and frequency number for each satellite in this epoch based on the frequency number discriminator;

[0009] Step 2: Adapt the cycle slip detection methods for three-frequency, two-frequency, and single-frequency based on the available frequency and the number of available frequencies;

[0010] Step 3: If, in step 2, it is determined that the epoch satellite should be compatible with the three-frequency cycle slip detection method, cycle slip test quantity and threshold of epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphere are constructed based on the frequency of the available three-frequency observation values, and three-frequency cycle slip detection is performed.

[0011] Step 4: If it is determined in Step 2 that the epoch satellite should be compatible with the dual-frequency cycle slip detection method, then based on the frequency of the available dual-frequency observations, establish the cycle slip check quantity and threshold of the epoch differential dual-frequency dual-difference carrier phase ionosphere-free combination, and perform dual-frequency cycle slip detection.

[0012] Step 5: If, in step 2, it is determined that the satellite of this epoch should be compatible with the single-frequency cycle slip detection method, then establish the cycle slip test quantity and threshold of the second epoch differential single-frequency double-difference carrier phase weak ionosphere combination, and perform single-frequency cycle slip detection.

[0013] Step 6: Based on the cycle slip detection results above, mark the corresponding carrier phase observation value for the epoch with cycle slips, and start data cycle slip detection for the next epoch.

[0014] Preferably, in the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided by the present invention, in step 3, a cycle slip check quantity ΔL is constructed for the epoch differential three-frequency pseudorange / carrier phase combination without geometry and without ionosphericity:

[0015]

[0016] In the formula, and P x These are the phase observation and pseudorange observation values ​​corresponding to frequency x, where x takes any value from (1,2,3), and f. x Let x be the observed frequency, λ be the wavelength of the three-frequency combination, λ1 be the wavelength of frequency 1, i,j,k,l,m,n be the combination coefficients, c be the speed of light, and Δ represent the continuous epoch difference.

[0017] Preferably, in the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided by the present invention, in step 4, a cycle slip check quantity ΔL is constructed for the epoch differential dual-frequency dual-difference carrier phase ionospheric combination:

[0018] ΔL=L(t)-L(t-1)

[0019]

[0020] In the formula, L represents the constructed dual-frequency dual-difference carrier phase-free combination. This indicates inter-station and inter-satellite double difference. and f x These are the phase observation value and the observation frequency corresponding to frequency x, where x takes the value of 1 or 2, and λ is the value of the phase observation value. x Let x be the wavelength of frequency x, r be the geometric distance between the station and the satellite, and ΔL = L(t) - L(t-1) represent the continuous epoch difference of the dual-frequency dual-difference carrier phase without ionosphere combination.

[0021] Preferably, the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided by the present invention, in step 5, constructs a cycle slip test quantity ΔL for a combination of second-epoch differential single-frequency double-difference carrier phase weak ionosphericity:

[0022]

[0023] In the formula, This indicates inter-station and inter-satellite double difference. t0 is the phase observation value, r is the geometric distance between the station and the satellite, t0 is the current time, t1 is the time of the next epoch, and t2 is the time of the epoch after that.

[0024] Preferably, in the adaptive frequency modulation cycle slip detection method that takes into account ionospheric changes provided by the present invention, in steps 3 to 5, the cycle slip discrimination is as follows: according to formula 4, when the cycle slip test quantity is greater than the cycle slip detection threshold of 3 times the combined observation noise, it is judged as a cycle slip;

[0025] |ΔL|>3σ ΔL (Formula 4).

[0026] Preferably, the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided by the present invention, in step 1, firstly constructs a receiver available frequency discriminator based on the observation header file, and presets the frequency and frequency number for each satellite; then, it performs available frequency discrimination on the satellite data input at the current epoch, and checks the carrier phase observation value of the specified bit in the header file. If the carrier phase observation value of the corresponding bit is empty, the corresponding frequency is unavailable, and the preset frequency number is decremented by one; and so on, it iterates through the carrier phase observation values ​​corresponding to all preset frequencies in the epoch, and finally determines the available frequency and available frequency number of each satellite in the epoch.

[0027] Preferably, the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided by the present invention, in step 2, selects cycle slip detection methods for different available frequencies based on the available frequency and available frequency number determined by the frequency number discriminator. If the available frequency number is three, a three-frequency cycle slip detection method is selected, and the process proceeds to step 3; if the available frequency number is two, a two-frequency cycle slip detection method is selected, and the process proceeds to step 4; if the available frequency number is one, a single-frequency cycle slip detection method is selected, and the process proceeds to step 5.

[0028] <System>

[0029] Furthermore, the present invention also provides an adaptive frequency-modulated cycle slip detection system that takes into account ionospheric changes, capable of automatically implementing the above-mentioned <method>, including:

[0030] The frequency number discrimination unit acquires carrier phase observation data and determines the available carrier phase observation frequency and frequency number of each satellite in this epoch based on the frequency number discrimination unit as the available frequency and available frequency number.

[0031] The adaptive unit adapts to three-frequency, two-frequency, and single-frequency cycle slip detection methods based on the available frequency and the number of available frequencies.

[0032] The three-frequency cycle slip detection unit, when the adaptive unit determines that the satellite of this epoch should be adapted to the three-frequency cycle slip detection method, constructs cycle slip check quantities and thresholds for the epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphere based on the frequency of the available three-frequency observations, and performs three-frequency cycle slip detection.

[0033] The dual-frequency cycle slip detection unit, when the adaptive unit determines that the satellite of this epoch should be adapted to the dual-frequency cycle slip detection method, constructs cycle slip check quantity and threshold of epoch differential dual-frequency dual-difference carrier phase ionosphere-free combination based on the frequency of available dual-frequency observations, and performs dual-frequency cycle slip detection.

[0034] The single-frequency cycle slip detection unit, when the adaptive unit determines that the satellite of this epoch should be adapted to the single-frequency cycle slip detection method, establishes the cycle slip check quantity and threshold of the second epoch differential single-frequency double-difference carrier phase weak ionosphere combination, and performs single-frequency cycle slip detection.

[0035] The marking unit, based on the cycle slip detection results mentioned above, marks the corresponding carrier phase observation value for that epoch with cycle slips and begins data cycle slip detection for the next epoch.

[0036] The control unit is communicatively connected to the frequency discrimination unit, the adaptive unit, the three-frequency cycle slip detection unit, the dual-frequency cycle slip detection unit, the single-frequency cycle slip detection unit, and the marking unit, and controls their operation.

[0037] Preferably, the adaptive frequency modulation cycle slip detection system that takes into account ionospheric changes provided by the present invention may further include: an input display unit, which is communicatively connected to the control unit, for allowing the user to input operation commands and displaying them accordingly.

[0038] Preferably, the adaptive frequency modulation cycle slip detection system provided by the present invention, which takes into account ionospheric changes, when the adaptive unit determines that the epoch satellite should be adapted to the three-frequency cycle slip detection method, controls the three-frequency cycle slip detection unit to construct the cycle slip verification quantity ΔL of the epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphericity:

[0039]

[0040] In formula 1, and P x These are the phase observation and pseudorange observation values ​​corresponding to frequency x, where x takes any value from (1,2,3), and f. x Let x be the observed frequency, λ be the wavelength of the three-frequency combination, λ1 be the wavelength of frequency 1, i,j,k,l,m,n be the combination coefficients, c be the speed of light, and Δ represent the continuous epoch difference.

[0041] If the adaptive unit determines that the satellite at this epoch should be adapted to the dual-frequency cycle slip detection method, the control unit controls the dual-frequency cycle slip detection unit to construct the cycle slip check quantity ΔL of the epoch differential dual-frequency dual-difference carrier phase ionospheric combination:

[0042] ΔL=L(t)-L(t-1)

[0043]

[0044] In Formula 2, L represents the constructed dual-frequency, dual-difference carrier phase-free combination. This indicates inter-station and inter-satellite double difference. and f x These are the phase observation value and the observation frequency corresponding to frequency x, where x takes the value of 1 or 2, and λ is the value of the phase observation value. x Let λ be the wavelength of frequency x, r be the geometric distance between the station and the satellite, and ΔL = L(t) - L(t-1) represent the continuous epoch difference of the dual-frequency dual-difference carrier phase without ionosphere.

[0045] If the adaptive unit determines that the satellite at this epoch should be adapted to the single-frequency cycle slip detection method, the control unit controls the single-frequency cycle slip detection unit to construct the cycle slip check quantity ΔL of the second epoch differential single-frequency double-difference carrier phase weak ionospheric combination:

[0046]

[0047] In formula 3, This indicates inter-station and inter-satellite double difference. t0 is the phase observation value, r is the geometric distance between the station and the satellite, t0 is the current time, t1 is the time of the next epoch, and t2 is the time of the epoch after that.

[0048] <Storage Media>

[0049] Furthermore, the present invention also provides a storage medium storing a program for performing the adaptive frequency-modulated cycle slip detection method that takes into account ionospheric changes as described in any of the methods.

[0050] The role and effect of invention

[0051] 1. This invention can adaptively adjust the three-frequency, dual-frequency, and single-frequency cycle slip detection strategies according to the actual observation frequency, overcoming problems such as receiver frequency drop, ionospheric activity during geological disasters, and missed detection of special types of cycle slips.

[0052] 2. This invention can specifically solve the problem of frequent cycle slips in complex environments and under active ionospheric conditions, and can reliably detect small cycle slips, large cycle slips, continuous cycle slips and insensitive cycle slips under active ionospheric conditions. Under ionospheric disturbance conditions, it can accurately detect different types of cycle slips.

[0053] 3. This invention can be widely applied to the data optimization of cycle slip detection by BeiDou / GNSS and other satellite navigation systems at monitoring stations in complex observation environments. Attached Figure Description

[0054] Figure 1 This is a flowchart of an adaptive frequency modulation cycle slip detection method that takes into account ionospheric changes, according to an embodiment of the present invention. Detailed Implementation

[0055] The following detailed description, in conjunction with the accompanying drawings, provides a detailed account of the specific implementation schemes of the adaptive frequency modulation cycle slip detection method, system, and storage medium that take into account ionospheric changes, as per the present invention.

[0056] <Example 1>

[0057] like Figure 1 As shown, the adaptive frequency modulation cycle slip detection method considering ionospheric changes provided in this embodiment includes the following steps (taking BeiDou / GNSS as an example):

[0058] S1: Input of BeiDou / GNSS carrier phase observation data. Based on the frequency discriminator, the available carrier phase observation frequencies for each satellite in this epoch are determined, specifically including:

[0059] S1-1: First, construct the available frequency discriminator for the receiver based on the observation header file, and preset the available frequencies and total available frequencies for BeiDou and various systems;

[0060] S1-2: Then, the available frequencies of the BeiDou / GNSS data input at the current epoch are determined, and the carrier phase observation values ​​of the specified bits in the header file are checked. If the carrier phase observation value of the corresponding bit is empty, the corresponding frequency is unavailable, and the number of available frequencies is reduced by one.

[0061] S1-3: By analogy, traverse all carrier phase observations corresponding to the preset frequencies in this epoch to determine the available frequencies and number of available frequencies for the satellite in this epoch.

[0062] S2: Based on the determined available frequencies and the number of available frequencies, adaptively adapt to three-frequency, dual-frequency, and single-frequency cycle slip detection methods. Specifically, this includes:

[0063] S2-1: First, based on the available frequency and available frequency number determined by the frequency discriminator, select the cycle slip detection method for different available frequencies. If the available frequency number is three (the satellite of this epoch has available three-frequency carrier phase observations), then select (adapted) three-frequency cycle slip detection method.

[0064] S2-2: If the number of available frequencies is two (the satellite at this epoch has available dual-frequency carrier phase observations), then select (adapted) dual-frequency cycle slip detection method;

[0065] S2-3: If the available frequency is one (the satellite of this epoch has available single-frequency carrier phase observations), then select (adapt) the single-frequency cycle slip detection method.

[0066] S3: If the epoch satellite is determined to be suitable for the three-frequency cycle slip detection method, then based on the frequencies of the available three-frequency observations, a cycle slip check quantity and threshold for the epoch differential three-frequency pseudorange / carrier phase combination without geometry or ionosphere are constructed, and three-frequency cycle slip detection is performed, specifically including:

[0067] S3-1: First, construct the cycle slip check ΔL for the epoch differential three-frequency pseudorange / carrier phase combination without geometry or ionosphere:

[0068]

[0069] In the formula, and P x Let f represent the phase observation value in cycles and the pseudorange observation value in meters, respectively, where x takes any value from (1,2,3). x Let x be the observed frequency, λ be the combined wavelength, i,j,k,l,m,n be the combination coefficients, and Δ represent the continuous epoch difference. In the combination coefficients, i,j,k are the determined carrier combination coefficients, such as (0,-1,1), while l,m,n are obtained by least squares estimation according to formula (1).

[0070] S3-2: Then perform cycle slip judgment. If the cycle slip test value is greater than the cycle slip detection threshold of 3 times the combined observation noise, it is judged as a cycle slip.

[0071] |ΔL|>3σ ΔL (2)

[0072] S4: If the epoch satellite is determined to be compatible with the dual-frequency cycle slip detection method, then based on the frequencies of the available dual-frequency observations, a cycle slip check quantity and threshold for the epoch differential dual-frequency dual-difference carrier phase ionospheric combination are constructed, and dual-frequency cycle slip detection is performed, specifically including:

[0073] S4-1: First, construct the cycle slip check ΔL for the epoch-differential dual-frequency dual-difference carrier phase-ionosphere-free combination:

[0074] ΔL=L(t)-L(t-1)

[0075]

[0076] In the formula, L represents the constructed dual-frequency dual-difference carrier phase-free combination. This indicates inter-station and inter-satellite double difference. and f x Let x represent the phase observation value and the observation frequency in weeks, respectively. x takes the value of 1 or 2. r is the geometric distance between the station and the satellite. For a quasi-static monitoring station, it can be obtained from the known coordinates of the station. ΔL = L(t) - L(t-1) represents the continuous epoch difference of the dual-frequency dual-difference carrier phase without ionospheric combination.

[0077] S4-2: Then perform cycle slip judgment. If the cycle slip test value is greater than the cycle slip detection threshold of 3 times the combined observation noise, it is judged as a cycle slip.

[0078] |ΔL|>3σ ΔL (4)

[0079] S5: If the satellite at this epoch is determined to be compatible with the single-frequency cycle slip detection method, then establish the cycle slip check quantity and threshold of the second-epoch differential single-frequency double-difference carrier phase weak ionospheric combination, and perform single-frequency cycle slip detection, specifically including:

[0080] S5-1: First, construct the cycle slip test ΔL for the second-epoch differential single-frequency double-difference carrier phase weak ionospheric combination:

[0081]

[0082] The symbols in the formula are consistent with those defined in formula (3);

[0083] S5-2: Then perform cycle slip judgment. If the cycle slip test value is greater than the cycle slip detection threshold of 3 times the combined observation noise, it is judged as a cycle slip.

[0084] |ΔL|>3σ ΔL (6)

[0085] S6: Based on the cycle slip detection results above, cycle slip marking is performed on the corresponding carrier phase observation values ​​for this epoch, and cycle slip detection of BeiDou / GNSS data for the next epoch begins.

[0086] Finally, the optimized BeiDou / GNSS observation files with cycle slip markings are output for data processing such as GNSS baseline calculation for monitoring stations.

[0087] In summary, this embodiment, by employing the above methods, can adaptively adjust the three-frequency, dual-frequency, and single-frequency cycle slip detection strategies according to the actual observation frequency, overcoming problems such as receiver frequency drop, ionospheric activity during geological disasters, and missed detection of special types of cycle slips. It can be reliably used for data optimization of BeiDou / GNSS cycle slip detection at monitoring stations under complex observation environments.

[0088] In addition, the above methods can be stored as computer programs in storage media. When the processor reads and runs the storage media, it executes the above methods to achieve cycle slip detection.

[0089] <Example 2>

[0090] Furthermore, this second embodiment provides an adaptive frequency modulation cycle slip detection system that takes into account ionospheric changes and can automatically implement the above-mentioned method of the present invention. The system includes a frequency number judgment unit, an adaptive unit, a three-frequency cycle slip detection unit, a dual-frequency cycle slip detection unit, a single-frequency cycle slip detection unit, a marking unit, an input display unit, and a control unit.

[0091] The frequency determination unit is used to perform the content described in step 1 above, acquire carrier phase observation data, and determine the frequency and frequency number of carrier phase observation available for each satellite in this epoch based on the frequency number discriminator as the available frequency and available frequency number.

[0092] The adaptive unit performs the functions described in step 2 above, and adapts (determines and selects) the cycle slip detection methods of three-frequency, two-frequency, and single-frequency based on the available frequency and the number of available frequencies.

[0093] The three-frequency cycle slip detection unit is used to perform the content described in step 3 above. When the adaptive unit determines that the epoch satellite should be adapted to the three-frequency cycle slip detection method, it constructs the cycle slip check quantity and threshold of the epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphere based on the frequency of the available three-frequency observation values, and performs three-frequency cycle slip detection.

[0094] The dual-frequency cycle slip detection unit is used to perform the content described in step 4 above. When the adaptive unit determines that the epoch satellite should be adapted to the dual-frequency cycle slip detection method, it constructs the cycle slip check quantity and threshold of the epoch differential dual-frequency dual-difference carrier phase ionosphere-free combination based on the frequency of the available dual-frequency observations, and performs dual-frequency cycle slip detection.

[0095] The single-frequency cycle slip detection unit is used to perform the content described in step 5 above. When the adaptive unit determines that the satellite of this epoch should be adapted to the single-frequency cycle slip detection method, it constructs the cycle slip check quantity and threshold of the second epoch differential single-frequency double-difference carrier phase weak ionosphere combination and performs single-frequency cycle slip detection.

[0096] The marking unit performs the functions described in step 6 above, marking the corresponding carrier phase observation for the epoch based on the cycle slip detection results, and starting the data cycle slip detection for the next epoch.

[0097] The input display unit is used to allow users to input operation commands and to display the input, output, and intermediate processing data of the corresponding units according to the operation commands.

[0098] The control unit is communicatively connected to the frequency judgment unit, adaptive unit, three-frequency cycle slip detection unit, dual-frequency cycle slip detection unit, single-frequency cycle slip detection unit, marking unit, and input display unit, and controls their operation.

[0099] The above embodiments are merely illustrative examples of the technical solutions of the present invention. The adaptive frequency modulation cycle slip detection method, system, and storage medium considering ionospheric changes involved in the present invention are not limited to the contents described in the above embodiments, but are defined by the scope of the claims. Any modifications, additions, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed by the claims of the present invention.

Claims

1. An adaptive frequency modulation cycle slip detection method that takes into account ionospheric changes, characterized in that, include: Step 1: Acquire carrier phase observation data, and determine the available carrier phase observation frequency and frequency number of each satellite in the current epoch based on the frequency number discriminator; Step 2: Adapt the cycle slip detection methods for three-frequency, two-frequency, and single-frequency based on the available frequency and the number of available frequencies; Step 3: If, in step 2, it is determined that the satellite at this epoch should be compatible with the three-frequency cycle slip detection method, cycle slip test quantity and threshold of epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphere are constructed based on the frequency of the available three-frequency observations, and three-frequency cycle slip detection is performed. Step 4: If, in step 2, it is determined that the satellite at this epoch should be compatible with the dual-frequency cycle slip detection method, then, based on the frequency of the available dual-frequency observations, establish the cycle slip check quantity and threshold of the epoch differential dual-frequency dual-difference carrier phase ionosphere-free combination, and perform dual-frequency cycle slip detection. Step 5: If, in step 2, it is determined that the satellite at this epoch should be compatible with the single-frequency cycle slip detection method, then establish the cycle slip test quantity and threshold of the second epoch differential single-frequency double-difference carrier phase weak ionosphere combination, and perform single-frequency cycle slip detection. Step 6: Based on the cycle slip detection results of Step 3, Step 4 or Step 5, mark the corresponding carrier phase observation value for the epoch with cycle slips, and start the data cycle slip detection for the next epoch.

2. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, characterized in that: in, In step 3, a cycle slip test quantity is constructed for the epoch differential three-frequency pseudorange / carrier phase geometry-free and ionosphere-free combination. : (Official 1) In the formula, and Frequency x The corresponding phase observations and pseudorange observations, x Take any value from (1,2,3). For frequency x The corresponding frequency of observations, It is a three-frequency combination wavelength. λ 1 represents the wavelength of frequency 1. For combination coefficients, At the speed of light, This represents the difference between consecutive epochs.

3. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, characterized in that: in, In step 4, the cycle slip test quantity of the epoch differential dual-frequency dual-difference carrier phase-ionosphere-free combination is constructed. : (Official 2) In the formula, This indicates a dual-frequency, dual-difference carrier phase-free combination. This indicates inter-station and inter-satellite double difference. and Frequency x The corresponding phase observations and observation frequencies, x Choose 1 or 2. λ x For frequency x wavelength, The geometric distance to the station star. This indicates a continuous epoch difference of dual-frequency dual-difference carrier phase without ionosphere.

4. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, characterized in that: in, In step 5, a cycle slip test quantity for a quadratic differential single-frequency double-difference carrier phase weak ionospheric combination is constructed. : (Official 3) In the formula, This indicates inter-station and inter-satellite double difference. For phase observations, Let t0 be the geometric distance to the star, t1 be the time of the next epoch, and t2 be the time of the epoch after that.

5. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, Its features are: in, In steps 3 to 5, cycle slip discrimination is as follows: according to formula 4, when the cycle slip test quantity is greater than the cycle slip detection threshold of 3 times the combined observation noise, it is judged as a cycle slip; (Official 4).

6. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, Its features are: in, In step 1, a receiver available frequency discriminator is first constructed based on the observation header file, and a preset frequency and frequency number are set for each satellite. Then, the available frequency is determined for the satellite data input at the current epoch, and the carrier phase observation value specified in the header file is checked. If the carrier phase observation value of the corresponding bit is empty, the corresponding frequency is unavailable, and the preset frequency number is reduced by one. By repeating this process, the carrier phase observations corresponding to all preset frequencies in that epoch are traversed to finally determine the available frequencies and available number of frequencies for each satellite in that epoch.

7. The adaptive frequency modulation cycle slip detection method considering ionospheric changes according to claim 1, Its features are: In step 2, based on the available frequency and available frequency number determined by the frequency discriminator, different cycle slip detection methods for different available frequencies are selected. If the available frequency number is three, the three-frequency cycle slip detection method is selected, and the process proceeds to step 3; if the available frequency number is two, the two-frequency cycle slip detection method is selected, and the process proceeds to step 4; if the available frequency number is one, the single-frequency cycle slip detection method is selected, and the process proceeds to step 5.

8. An adaptive frequency modulation cycle slip detection system that takes into account ionospheric changes, characterized in that, include: The frequency number discrimination unit acquires carrier phase observation data and determines the available carrier phase observation frequency and frequency number of each satellite in the current epoch based on the frequency number discrimination unit as the available frequency and available frequency number. The adaptive unit adapts to three-frequency, two-frequency, and single-frequency cycle slip detection methods based on the available frequency and the number of available frequencies. The three-frequency cycle slip detection unit, when the adaptive unit determines that the satellite at this epoch should be adapted to the three-frequency cycle slip detection method, constructs cycle slip check quantities and thresholds for the epoch differential three-frequency pseudorange / carrier phase without geometry and without ionosphere based on the frequency of the available three-frequency observation values, and performs three-frequency cycle slip detection. The dual-frequency cycle slip detection unit, when the adaptive unit determines that the satellite at this epoch should be adapted to the dual-frequency cycle slip detection method, constructs the cycle slip check quantity and threshold of the epoch differential dual-frequency dual-difference carrier phase ionosphere-free combination based on the frequency of the available dual-frequency observations, and performs dual-frequency cycle slip detection. The single-frequency cycle slip detection unit, when the adaptive unit determines that the satellite of this epoch should be adapted to the single-frequency cycle slip detection method, establishes the cycle slip check quantity and threshold of the second epoch differential single-frequency double-difference carrier phase weak ionospheric combination, and performs single-frequency cycle slip detection. The marking unit, based on the cycle slip detection results of the three-frequency cycle slip detection unit, the two-frequency cycle slip detection unit, or the single-frequency cycle slip detection unit, marks the corresponding carrier phase observation value for the epoch and begins data cycle slip detection for the next epoch. The control unit is communicatively connected to the frequency discrimination unit, the adaptive unit, the three-frequency cycle slip detection unit, the dual-frequency cycle slip detection unit, the single-frequency cycle slip detection unit, and the marking unit, and controls their operation.

9. The adaptive frequency modulation cycle slip detection system considering ionospheric changes according to claim 8, characterized in that: in, If the adaptive unit determines that the satellite at this epoch should be compatible with the three-frequency cycle slip detection method, the control unit controls the three-frequency cycle slip detection unit to construct a cycle slip check quantity for an epoch differential three-frequency pseudorange / carrier phase combination without geometry or ionosphere. : (Official 1) In formula 1, and Frequency x The corresponding phase observations and pseudorange observations, x Take any value from (1,2,3). For frequency x The corresponding frequency of observations, It is a three-frequency combination wavelength. λ 1 represents the wavelength of frequency 1. For combination coefficients, At the speed of light, Represents the difference between consecutive epochs; If the adaptive unit determines that the satellite at this epoch should be adapted to the dual-frequency cycle slip detection method, the control unit controls the dual-frequency cycle slip detection unit to construct a cycle slip check quantity for an epoch differential dual-frequency dual-difference carrier phase ionospheric combination. : (Official 2) In formula 2, This indicates a dual-frequency, dual-difference carrier phase-free combination. This indicates inter-station and inter-satellite double difference. and Frequency x The corresponding phase observations and observation frequencies, x Choose 1 or 2. λ x For frequency x wavelength, The geometric distance to the station star. This represents a continuous epoch difference of dual-frequency dual-difference carrier phase without ionosphere; If the adaptive unit determines that the satellite at this epoch should be adapted to the single-frequency cycle slip detection method, the control unit controls the single-frequency cycle slip detection unit to construct a cycle slip verification quantity for a second-epoch differential single-frequency double-difference carrier phase weak ionospheric combination. : (Official 3) In formula 3, This indicates inter-station and inter-satellite double difference. For phase observations, Let t0 be the geometric distance to the star, t1 be the time of the next epoch, and t2 be the time of the epoch after that.

10. A storage medium, characterized in that: The system stores a program for performing the adaptive frequency-modulated cycle slip detection method that takes into account ionospheric changes as described in any one of claims 1 to 7.

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