A service text abnormality monitoring method and system based on a satellite-based augmentation system

Abstract

The application provides a service text abnormality monitoring method and system based on a satellite-based augmentation system, and belongs to the field of satellite navigation and satellite-based augmentation. The method first acquires an augmentation text generated by a master control station based on observation data of an observation station, and performs static checking on the augmentation text. If the static checking passes, the augmentation text is uploaded. The broadcasted augmentation text is received, and the consistency between the satellite and the ground is compared in real time, the observation quality is evaluated based on O-C residual error to verify the augmentation effect of the augmentation text, and precise point positioning (PPP) integrity test is performed based on a monitoring station. If the test passes, the service text is normal. If the static checking does not pass and it is determined that there is a static abnormality, or the consistency comparison between the satellite and the ground is abnormal, or the O-C residual error verification does not pass, or the positioning test does not pass and it is determined that the monitoring station PPP positioning is abnormal, a rule library or an algorithm model is constructed, and fault correlation and positioning are performed according to the determination result. The application improves the abnormality monitoring capability of the augmentation text.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation and satellite-based augmentation, and specifically relates to a method and system for monitoring service message anomalies based on a satellite-based augmentation system. Background Technology

[0002] As a key infrastructure for improving the accuracy, integrity, continuity, and availability of satellite navigation systems, satellite-based augmentation systems have developed into a complete technical system after more than 30 years of development. Currently, multiple regional satellite-based augmentation systems have been established globally, including China's BDSBAS and PPP-B2b service, the US's WAAS, Europe's EGNOS, and Japan's MSAS. These systems broadcast differential correction information and integrity parameters via geostationary orbit (GEO) satellites or other medium- and high-orbit satellites, providing augmentation services for high-safety-requirement fields such as aviation and maritime navigation. Satellite-based augmentation systems adopt a three-tier architecture: the ground segment consists of a wide network of monitoring stations distributed over thousands of kilometers, responsible for collecting raw GNSS observation data, which is then processed by the master control station to generate augmentation information, including satellite orbit corrections, clock corrections, and ionospheric delay grids; the space segment broadcasts the augmentation information to users via GEO satellites or other medium- and high-orbit satellites. User receivers use the received message information to improve positioning accuracy and experience highly reliable and high-integrity services. Ensuring the proper transmission of service messages is crucial for improving user experience; therefore, real-time monitoring of messages is necessary.

[0003] In existing technologies, message monitoring is generally conducted by assessing signal distortion or performance, with a focus on the impact of the ionosphere on the signal. For example, Chinese patent CN202411575501.2 discloses a performance evaluation method and device for satellite-based augmentation navigation. This method boasts significant advantages, including ensuring comprehensive evaluation by dividing the entire evaluation area into grid points, achieving adaptive sampling through dynamically adjusted latitude and longitude intervals, effectively identifying and quantifying augmentation service errors through a precise positioning model, and objectively reflecting the actual positioning performance of satellite-based augmentation services. However, this approach is highly dependent on the accuracy and reliability of reference orbit data and clock bias data, and its high computational complexity may affect evaluation efficiency. Furthermore, the model's adaptability to different environmental conditions in practical applications needs further verification, and the evaluation accuracy may be limited for boundary areas and special terrains. For example, Chinese patent CN202010045376.X discloses a method for monitoring ionospheric anomalies in a ground-based augmentation system. This method calculates the cumulative delay value by accumulating the estimated matrix of ionospheric delay, thereby monitoring whether ionospheric messages are abnormal. However, this scheme only focuses on messages that are abnormal in the ionosphere during broadcast, ignoring other links and failing to achieve closed-loop monitoring. Therefore, the main drawbacks of existing technologies include: 1) fragmented monitoring links: existing solutions are limited to a single node in the navigation system, making true closed-loop management difficult; 2) insufficient fault location capabilities: when service anomalies occur, existing technologies may only be able to rule out abnormal satellites without tracing the root cause, or although they can detect anomalies, they cannot accurately pinpoint whether it is a ground injection error or an onboard equipment malfunction, leading to low maintenance efficiency; 3) imbalance between resource allocation and engineering feasibility: either excessively high requirements for user-end computing resources affecting real-time performance, placing complex computing loads on the satellite restricting efficiency, or adopting highly integrated solutions significantly increasing system complexity and cost. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, the present invention aims to provide a service message anomaly monitoring method and system based on satellite-based augmentation system. By constructing a triple collaborative monitoring mechanism of ground feedforward verification, satellite-ground consistency comparison and user terminal integrity assessment, the present invention implements full-link, multi-dimensional monitoring and accurate fault location of augmentation service messages, thereby improving the reliability and security of augmentation services.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] In a first aspect, embodiments of the present invention provide a method for monitoring service message anomalies based on a satellite-based augmentation system, the method comprising the following steps:

[0007] Step S1: Obtain the enhanced message generated by the master control station based on the observation data from the observation station;

[0008] Step S2: After the enhanced message is generated by the ground master control station and before it is injected into the satellite, a static check is performed on the enhanced message; if the static check passes, proceed to step S3; if the static check fails, it is determined that there is a static anomaly, and proceed to step S7.

[0009] Step S3: Upload the enhanced message to the corresponding enhanced information broadcasting satellite, and broadcast the enhanced message by the enhanced information broadcasting satellite;

[0010] Step S4: Receive the broadcast enhanced message and compare the satellite-to-ground consistency in real time; if the comparison passes, proceed to step S5; if the comparison fails, proceed to step S7.

[0011] Step S5: Observation quality assessment is performed based on OC residuals to verify the enhancement effect of the enhanced message; if the verification is successful, proceed to step S6; if the verification fails, the OC residuals are determined to be abnormal, and proceed to step S7.

[0012] Step S6: Within the enhanced service range, deploy several monitoring stations equivalent to user terminals, and perform a precise single-point positioning PPP integrity test based on the monitoring stations; if the test passes, the service message is normal; if the test fails, it is determined that the PPP positioning of the monitoring station is abnormal, and proceed to step S7.

[0013] Step S7: Construct a rule base or algorithm model, and perform fault association and location based on the judgment results.

[0014] In a preferred embodiment of the present invention, step S2 performs a static check on the enhanced message, including:

[0015] Step S21: Check the rationality of the parameters; if the test value of any parameter is negative, it is determined that there is a static anomaly in the current enhanced message; if the test values ​​of all parameters are positive, proceed to step S22.

[0016] Step S22: Check the consistency between the orbit and clock difference extrapolation; if any value exceeds the alarm threshold range, it is determined that the message does not meet the extrapolation consistency and the current enhanced message has a static anomaly; if all values ​​are within the alarm threshold range, it is determined that the current enhanced message passes the static check and is allowed to be added.

[0017] In a preferred embodiment of the present invention, step S22, which involves verifying the consistency between the orbit and the clock difference extrapolation, includes the following steps:

[0018] Step S221: Calculate the future satellite position sequence after enhancement over a predetermined time period using the broadcast message and the enhanced message to be added. and enhanced satellite clock sequence ; These are the coordinates of the satellite's position in the Earth-fixed coordinate system;

[0019] Step S222: Obtain the post-hoc precise satellite position sequence of the navigation satellites from the master control station. and precision clock difference sequence As a reference truth value;

[0020] Step S223: Calculate the orbital error vector based on the enhanced position sequence and the precise position sequence, using the following formula:

[0021] (3)

[0022] In equation (3), Represents the orbital error vector. These represent the position differences along the three axes in the Earth-fixed coordinate system;

[0023] Step S224, convert the orbital error vector Transform from the Earth-fixed coordinate system to the local orbital coordinate system of the satellite along the radial direction R, the track A, and the normal direction C, respectively;

[0024] Step S225: Based on the enhanced clock error sequence and the precise clock error sequence, calculate the clock error and convert it into an equivalent ranging error.

[0025] (4)

[0026] In equation (4), The speed of light;

[0027] Step S226: Based on the ranging error, the SISRE approximation model for spatial signal ranging error is used for calculation:

[0028] (5)

[0029] In equation (5), These represent the components of the broadcast track error in the tangential, normal, and radial directions, respectively. This represents the error in broadcast clock bias, expressed in meters (m). Represents weighting factors. Indicates the distance measurement error;

[0030] Step S227: Calculate the maximum value, average value and 95th percentile of the ranging error within the preset time period, and compare them with the preset alarm thresholds respectively; if any value exceeds the alarm threshold range, it is determined that the message does not meet the extrapolation consistency; if all values ​​are within the alarm threshold range, it is determined that the message passes the static check and is allowed to be bet.

[0031] In a preferred embodiment of the present invention, during the real-time comparison of satellite-to-ground consistency in step S4, bit-level comparison of the message content is performed, specifically including:

[0032] The monitoring station receiver demodulates and decodes the satellite downlink radio frequency signal to fully recover the enhanced message data block, ensuring the transmission of the enhanced message broadcast by the satellite. This is the data that the receiver considers correct; from the ground control system, the corresponding enhanced messages that should have been uploaded to the satellite are acquired in real time. ;

[0033] right and Perform time matching and execute the consistency function:

[0034] (6)

[0035] In equation (6), Represents a consistency function;

[0036] If all fields are completely identical, the result is "Match," indicating a match; otherwise, the result is "Mismatch," indicating an anomaly.

[0037] In a preferred embodiment of the present invention, step S5, which assesses the observation quality based on the OC residual, includes the following steps:

[0038] Step S51: The pseudorange observation value is obtained directly by the monitoring receiver. ;

[0039] Step S52, calculate the pseudorange value ;

[0040] Step S53, calculate the OC residual, using the following formula:

[0041] (8)

[0042] In equation (8), The OC residual represents the observed value. Compared with calculated values difference;

[0043] Step S54, calculate each satellite Residual statistics within a preset time period;

[0044] Step S55: If the residual statistic or the OC residual of a single epoch exceeds the alarm threshold set based on historical data, it is determined that the satellite broadcast message has a systematic deviation at the physical level.

[0045] In a preferred embodiment of the present invention, the pseudorange calculation value is calculated in step S52. The formula is as follows:

[0046] (7)

[0047] In equation (7), Indicates the satellite's location; This indicates the precisely known coordinates of the monitoring station; Indicates satellite clock bias; Indicates receiver clock bias; These represent the delay corrections for the ionosphere and troposphere, respectively. This represents the relativistic effect correction term.

[0048] In a preferred embodiment of the present invention, the PPP positioning integrity check is performed in step S6, and the steps are as follows:

[0049] Step S61: Based on the broadcast messages, enhanced messages and observations received by the monitoring station, calculate the PPP and PPP error;

[0050] Step S62: Preset a PPP error threshold for each monitoring station; determine whether the current monitoring station has a PPP positioning error that continuously exceeds the threshold within a predetermined time period; if so, determine that the test has failed and proceed to step S7.

[0051] As a preferred embodiment of the present invention, the PPP calculation formula is as follows:

[0052] (10)

[0053] (11)

[0054] In equations (10) and (11), Indicates satellite and signal frequency; These represent the pseudorange and carrier phase observations, respectively. Indicates the geometric distance between the user and the satellite; This indicates the broadcast clock error corrected by the enhanced message; Indicates receiver clock bias; These are the delay corrections for the ionosphere and troposphere, respectively. These represent the pseudorange code deviations of the receiver and the satellite, respectively. These represent the phase hardware delays of the receiver and the satellite, respectively. These represent the integer ambiguity of the carrier wavelength and phase observation, respectively; These represent pseudorange and carrier observation noise, respectively.

[0055] The formula for calculating PPP positioning error is as follows:

[0056] (12)

[0057] In equation (12), This represents the calculated coordinates of the receiver in the Earth-fixed coordinate system. This represents the known precise coordinate reference value of the monitoring station.

[0058] In a preferred embodiment of the present invention, step S7 involves fault association and location based on the determination result, including:

[0059] When a static anomaly is detected in the enhanced message, an enhanced message generation fault alarm is triggered, preventing the message from being uploaded. The fault is located in the ground master control station generation system, and an error analysis report is recorded to allow ground maintenance personnel to investigate potential problems in the master control station's orbit determination and prediction algorithm; this is the result R1.

[0060] When an anomaly is detected in the real-time comparison of satellite-to-ground consistency, a bit comparison alarm is triggered, the fault is located in the ground uplink injection chain or the satellite's storage / processing unit, and a check of the uplink injection station and onboard data management system is prompted; as result R2;

[0061] When an OC residual is determined to be abnormal, an OC residual alarm is triggered. The fault is located in the physical deviation of the satellite's Sat-C signal generation unit. The satellite is marked as unusable or used with reduced accuracy, and its health status is broadcast. This is the result R3.

[0062] If a single monitoring station is determined to have an abnormal PPP positioning, while its surrounding stations are normal, the positioning fault is due to an issue with the enhanced message precision correction number. The monitoring station is marked as suspicious, but no system-level alarm is triggered; this is the result R4.

[0063] If it is determined that at least two monitoring stations have abnormal PPP positioning, it is then confirmed whether the abnormal positioning is caused by an abnormal enhanced message of Sat-D. Based on the combined results R1, R2, R3 and R4, the fault is located on the ground, uplink or satellite.

[0064] Secondly, embodiments of the present invention provide a service message anomaly monitoring system based on a satellite-based augmentation system. The system includes: an augmentation message acquisition module, a static inspection module, a broadcast message acquisition module, a satellite-to-ground consistency comparison module, an OC residual assessment module, a positioning integrity verification module, a database, and a fault association and location module; wherein...

[0065] The enhanced message acquisition module is used to acquire the enhanced message generated by the main control station based on the observation data of the observation station.

[0066] The static check module is used to perform a static check on the enhanced message after it is generated by the ground master control station and before it is injected into the satellite. If the static check passes, uplink injection is allowed; if the static check fails, the fault association and location module is activated.

[0067] The broadcast message acquisition module is used to acquire the enhanced message broadcast by the enhanced information broadcasting satellite;

[0068] The satellite-to-ground consistency comparison module is used to compare satellite-to-ground consistency in real time; if the comparison passes, the OC residual evaluation module is activated; if the comparison fails, the fault association and location module is activated.

[0069] The OC residual assessment module is used to assess the observation quality based on the OC residual to verify the enhancement effect of the enhanced message; if the verification is successful, the positioning integrity check module is activated; if the verification fails, the OC residual is determined to be abnormal, and the fault association and positioning module is activated.

[0070] The positioning integrity verification module is used to deploy several monitoring stations equivalent to user terminals within the enhanced service range, and to perform precise single-point positioning PPP integrity verification based on the monitoring stations; if the verification passes, the service message is normal; if the verification fails, it is determined that the PPP positioning of the monitoring station is abnormal, and the fault association and positioning module is activated.

[0071] The database is used to store rule bases or algorithm models;

[0072] The fault association and location module is used to perform fault association and location based on a rule base or algorithm model and the judgment result. The technical solution provided by the embodiments of the present invention has the following beneficial effects:

[0073] The service message anomaly monitoring method and system based on a satellite-based augmentation system provided in this invention constructs a comprehensive augmentation service message monitoring and fault location system covering the entire "generation-injection-broadcast-application" link. It uses ground-based feedforward verification to predict parameter rationality and correction efficiency before augmentation message injection, intercepting abnormal messages at the source. It achieves bit-level data verification and multi-level positioning effect evaluation through satellite-ground consistency comparison. Finally, it forms a complete closed-loop monitoring system through user-end positioning performance monitoring and an intelligent fault diagnosis engine. This invention achieves comprehensive verification from data correctness to service effectiveness, enabling early detection and accurate location of faults in the augmentation message generation system, satellite uplink injection link, onboard storage and processing unit, and original navigation signals. This significantly improves the reliability, integrity, and operational efficiency of satellite-based augmentation services, providing solid technical support for high-safety-requirement fields such as aviation and maritime transport.

[0074] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0075] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 This is a schematic diagram illustrating the principle of service message anomaly monitoring based on a satellite-based augmentation system as described in an embodiment of the present invention;

[0077] Figure 2 This is a flowchart of the service message anomaly monitoring method based on a satellite-based augmentation system as described in an embodiment of the present invention. Detailed Implementation

[0078] After discovering the aforementioned problems, the inventors of this application conducted a detailed study of the existing service message monitoring process based on satellite-based augmentation systems. The study revealed several abnormal stages in the entire chain of augmentation information generation and broadcasting that could lead to service performance degradation or even failure. When the master control station processes the generation of differential corrections and integrity parameters, errors in the augmentation information itself may occur due to algorithm defects, abnormal input data, or model bias. During the uplink injection phase, message data may experience bit flips or loss due to channel interference or equipment failure. Furthermore, in the GEO satellite or other medium-to-high orbit satellite relay stage, onboard processing anomalies or signal generation unit malfunctions may cause inconsistencies between the broadcast signal and the injected message. Even a tiny bit error, if occurring at a critical parameter location, can cause the entire set of augmentation corrections to fail, not only failing to improve user positioning accuracy but also potentially worsening user positioning accuracy due to the broadcast of erroneous information, posing a serious threat to high-security applications such as aviation. Therefore, constructing an augmentation message monitoring and fault location system covering the entire chain of "generation-injection-relay-application" is the core key to ensuring the reliability of augmentation services.

[0079] It should be noted that the defects in the above-mentioned prior art solutions are all results obtained by the inventors after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present invention in the following text should be considered as contributions made by the inventors to the present invention.

[0080] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0081] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0082] After the above in-depth analysis, the embodiments of the present invention provide a service message anomaly monitoring method and system based on a satellite-based augmentation system. It can perform full-link, multi-dimensional monitoring and accurate fault location of augmentation service messages. By constructing a triple collaborative monitoring mechanism of ground feedforward verification, satellite-ground consistency comparison and user terminal integrity assessment, and integrating an intelligent fault diagnosis engine, it realizes closed-loop management of the entire process of augmentation service messages from generation, uploading to broadcasting, thereby discovering faults early and accurately locating fault links, and comprehensively improving the reliability and security of augmentation services.

[0083] like Figure 1 and Figure 2 As shown, the service message anomaly monitoring method based on satellite-based augmentation system includes the following steps:

[0084] Step S1: Obtain the enhanced message generated by the master control station based on the observation data from the observation station.

[0085] In this step, based on the main layout and functions of the satellite-based augmentation system, enhanced messages are calculated and generated using observation data from the observatories. This is a basic operation of the satellite-based augmentation system and forms the foundation for its message enhancement function.

[0086] Step S2: After the enhanced message is generated by the ground master control station and before it is injected into the satellite, a static check based on rules and physical laws is performed to ensure that the enhanced message parameters themselves have reasonable physical meaning and the expected enhancement effect. If the static check passes, proceed to step S3; if the static check fails, proceed to step S7.

[0087] This step intercepts augmented messages with anomalies or substandard performance at the source by inspecting the messages before uploading them to the satellite. The static check based on rules and physical laws includes verifying the rationality of the augmented message parameters and verifying the consistency between orbit and clock extrapolation. The specific steps are as follows:

[0088] Step S21: Verify the rationality of the parameters; if any parameter test value is negative, it is determined that there is a static anomaly in the current enhanced message; if all parameter test values ​​are positive, proceed to the track and clock difference extrapolation consistency verification procedure and proceed to step S22.

[0089] In practice, threshold and logical judgments are performed on all key parameters in the enhanced message, including basic parameters and integrity parameters. Specifically, this includes:

[0090] Check that the ephemeris reference time Toe and the clock parameter reference time Toc are within a reasonable time range, ensuring that they are neither too far in the past nor too far in the future.

[0091] Check whether the magnitudes of the orbital correction and clock error correction are within a reasonable threshold set based on the historical dynamic range; the algorithm is as follows:

[0092] (1)

[0093] (2)

[0094] In equations (1) and (2), Indicates the orbital correction number. and These represent the theoretical minimum and maximum values ​​of the correction.

[0095] Check whether the vertical delay values ​​and their rate of change of the grid points conform to the general physical laws of regional ionospheric activity and whether they conform to the reasonable values ​​of the ionospheric grid correction.

[0096] Verify that integrity parameters such as User Differential Range Error (UDRE) and Grid Ionospheric Vertical Error (GIVE) are within the valid range;

[0097] Check whether the dual frequency ranging error (DFRE) matches the expected performance.

[0098] Step S22: Check the consistency between orbit and clock difference extrapolation; if any value exceeds the alarm threshold range, it is determined that the message does not meet the extrapolation consistency, the current enhanced message has a static anomaly, and proceed to step S7 to trigger an alarm and prevent uploading; at the same time, record a detailed error analysis report for ground operation and maintenance personnel to check potential problems in the master control station orbit determination prediction algorithm; if all values ​​are within the alarm threshold range, it is determined that the current enhanced message has passed the static check and uploading is allowed.

[0099] Specifically, the steps include the following:

[0100] Step S221: Calculate the future satellite position sequence after enhancement over a predetermined time period using the broadcast message and the enhanced message to be added. and enhanced satellite clock sequence ; These are the coordinates of the satellite's position in the Earth-fixed coordinate system.

[0101] Step S222: Obtain the post-flash precise position sequence of navigation satellites from the master control station. and precision clock difference sequence As a reference truth value;

[0102] Step S223: Calculate the orbital error vector based on the enhanced position sequence and the precise position sequence, using the following formula:

[0103] (3)

[0104] In equation (3), Represents the orbital error vector. These represent the positional differences along the three axes in the Earth-fixed coordinate system.

[0105] Step S224, convert the orbital error vector Transform from the Earth-fixed coordinate system to the satellite's local orbital coordinate system (radial R, along the track A, normal C).

[0106] Step S225: Based on the enhanced clock error sequence and the precise clock error sequence, calculate the clock error and convert it into an equivalent ranging error.

[0107] (4)

[0108] In equation (4), It is the speed of light.

[0109] Step S226: Based on the ranging error, the SISRE approximation model for spatial signal ranging error is used for calculation:

[0110] (5)

[0111] In equation (5), These represent the components of the broadcast track error in the tangential, normal, and radial directions, respectively. This represents the error in broadcast clock bias, expressed in meters (m). This represents the weighting factor, the value of which depends on the altitude and cutoff elevation angle of the GNSS satellite. This indicates the distance measurement error.

[0112] Step S227: Calculate the maximum, average, and 95th percentile of the ranging error throughout the entire cycle, and compare them with preset alarm thresholds. If any value exceeds the alarm threshold range, the message is deemed to be inconsistent with extrapolation consistency, and the process proceeds to step S7. An alarm is triggered, and uploading is prevented. Simultaneously, a detailed error analysis report is recorded for ground maintenance personnel to investigate potential problems with the master control station's orbit determination and prediction algorithm. If all values ​​are within the alarm threshold range, the message is deemed to have passed the static check and uploading is permitted.

[0113] Step S3: Upload the enhanced message to the corresponding enhanced information broadcasting satellite, and broadcast the enhanced message by the enhanced information broadcasting satellite.

[0114] Step S4: Receive the broadcast enhanced message, compare the satellite-to-ground consistency in real time, and verify whether the message has been damaged during transmission after broadcasting, so as to confirm whether the satellite broadcast enhanced message and the message injected into the satellite from the ground are completely consistent at the bit level; if the comparison is successful, proceed to step S5; if the comparison is abnormal, proceed to step S7.

[0115] This step involves real-time comparison of satellite-to-ground consistency, that is, bit-level comparison of the message content, specifically including:

[0116] The monitoring station receiver demodulates and decodes the satellite downlink radio frequency signal to fully recover the enhanced message data block, ensuring the transmission of the enhanced message broadcast by the satellite. This is the data that the receiver considers correct; it retrieves the corresponding enhanced message that should have been uploaded to the satellite in real time from the database or data stream of the ground control system. Due to delays in message transmission and processing, it is necessary to determine the time based on the reference time in the message and the received timestamp. and Precise time matching is performed to ensure that the compared messages are of the same version. Specifically, during bit-level comparison, a consistency function is executed:

[0117] (6)

[0118] In equation (6), The consistency function compares the satellite broadcast message with the ground-injected message field by field. If all fields are completely consistent, the result is considered a match, meaning the comparison is consistent.

[0119] If the comparison results are consistent, it proves that the integrity of the entire data link from ground generation and satellite uploading to satellite broadcasting is guaranteed, and the process enters the next stage of physical-level verification.

[0120] If the result is an anomaly, a critical alarm is immediately triggered, and the fault is marked as occurring in the storage, processing, or modulation unit of the ground uplink injection link or the satellite itself. The above-mentioned fault confirmation and processing process is completed in step S7.

[0121] Step S5: Based on the OC residual, conduct an observation quality assessment to verify the enhancement effect of the enhanced message, confirm whether the enhanced message broadcast by the satellite can obtain accurate satellite position and clock error at the physical level, thereby supporting high-precision positioning; if the verification is successful, proceed to step S6; if the verification fails, it is determined that the OC residual is abnormal, and proceed to step S7.

[0122] This step, assuming bit alignment is consistent, involves a more in-depth physical layer verification to validate the enhancement effectiveness of the enhanced message and to assess observation quality based on OC residuals. Specifically, this includes:

[0123] Step S51: The pseudorange observation value is obtained directly by the monitoring receiver. ;

[0124] Step S52, calculate the pseudorange value The formula is as follows:

[0125] (7)

[0126] In equation (7), Indicates the satellite's location; This indicates the precisely known coordinates of the monitoring station; Indicates satellite clock bias; This indicates the receiver clock bias (which can be estimated through multi-satellite observations or provided by an external high-precision clock); These represent the delay corrections for the ionosphere and troposphere, respectively. This represents the relativistic effect correction term.

[0127] Step S53, calculate the OC residual:

[0128] (8)

[0129] In equation (8), The OC residual represents the observed value. Compared with calculated values difference.

[0130] Step S54, with the error correction complete, It should be close to zero-mean white noise. For each satellite Calculate the residual statistics, such as root mean square error, within a preset time period. :

[0131] (9)

[0132] In equation (9), This represents the root mean square error of the OC residuals of the satellite during the statistical period.

[0133] Step S55: If the residual statistic or the OC residual of a single epoch exceeds the alarm threshold set based on historical data, it is determined that the satellite broadcast message has a systematic deviation at the physical level.

[0134] For each satellite A dynamic or static alarm threshold is set. When the threshold is exceeded, a systematic deviation in the satellite broadcast message is determined. Since the bit comparison has passed, this fault can no longer be a simple data transmission error, but must be located at a physical deviation in the satellite's signal generation unit. For example, abnormal frequency drift or jumps in the onboard atomic clock cause the broadcast clock error after enhanced ephemeris correction to be inconsistent with the actual error.

[0135] Step S6: Within the enhanced service range, deploy several monitoring stations equivalent to user terminals, and perform a precise single-point positioning PPP integrity test based on the monitoring stations; if the test passes, the service message is normal; if the test fails, it is determined that the PPP positioning of the monitoring station is abnormal, and proceed to step S7.

[0136] In this step, the monitoring station, which is equivalent to the user terminal, is implemented by deploying multiple performance monitoring stations as virtual users over a wide area.

[0137] The specific steps for verifying the integrity of PPP positioning are as follows:

[0138] Step S61: Based on the broadcast message, enhanced message and observations received by the monitoring station, calculate the Precise Point Positioning (PPP) and PPP error.

[0139] The PPP solution formula in this step is as follows:

[0140] (10)

[0141] (11)

[0142] In equations (10) and (11), Indicates satellite and signal frequency; These represent the pseudorange and carrier phase observations, respectively. Indicates the geometric distance between the user and the satellite; This indicates the broadcast clock error corrected by the enhanced message; This indicates the receiver clock bias (which can be estimated through multi-satellite observations or provided by an external high-precision clock); These are the delay corrections for the ionosphere and troposphere, respectively. These represent the pseudorange code deviations of the receiver and the satellite, respectively. These represent the phase hardware delays of the receiver and the satellite, respectively. These represent the integer ambiguity of the carrier wavelength and phase observation, respectively; These represent pseudorange and carrier observation noise, respectively.

[0143] Extended Kalman filter is used to estimate the state vector. The time required from the start of filtering until the positioning error first falls below the threshold, and the standard deviation of the positioning error after convergence are calculated. The calculated position is then used to calculate the position. With known truth value Compare.

[0144] And calculate the 3D PPP positioning error:

[0145] (12)

[0146] In equation (12), This represents the calculated coordinates of the receiver in the Earth-fixed coordinate system. This represents the known precise coordinate reference value of the monitoring station.

[0147] Step S62: Preset a PPP error threshold for each monitoring station; determine whether the current monitoring station has a PPP positioning error that continuously exceeds the threshold within a predetermined time period; if so, determine that the test has failed and proceed to step S7.

[0148] In this step, "continuously exceeding the threshold" means that the PPP positioning error continuously exceeds the threshold within a preset time period.

[0149] Step S7: Construct a rule base or algorithm model, and perform fault association and localization based on the judgment results. Specific operations include:

[0150] When a static anomaly is detected in the enhanced message, an enhanced message generation fault alarm is triggered, preventing the message from being uploaded. The fault is located in the ground master control station generation system (specifically, the orbit determination / forecasting module that generates Sat-A messages). At the same time, a detailed error analysis report is recorded for ground maintenance personnel to investigate potential problems in the master control station's orbit determination and forecasting algorithm; this is the result R1.

[0151] When an anomaly is detected in the real-time comparison of satellite-to-ground consistency, a bit comparison alarm is triggered, the fault is located in the ground uplink injection chain or the satellite's storage / processing unit, and a check of the uplink injection station and onboard data management system is prompted; as result R2;

[0152] When an OC residual is determined to be abnormal, an OC residual alarm is triggered. The fault is located in the physical deviation of the satellite's Sat-C body signal generation unit (such as abnormal onboard atomic clock or attitude control). The satellite is marked as unusable or used with reduced accuracy, and its health status is broadcast; as a result R3.

[0153] When a single monitoring station is determined to have an abnormal PPP positioning, and its surrounding stations are normal, the positioning fault is due to an enhanced message precision correction problem, such as receiver failure, multipath interference, or local radio interference. The station is marked as suspicious, but no system-level alarm is triggered; this is the result R4.

[0154] If it is determined that at least two monitoring stations have abnormal PPP positioning, it is then confirmed whether the abnormal positioning is caused by an abnormal enhanced message of Sat-D. Based on the combined results R1, R2, R3 and R4, the fault is located on the ground, uplink or satellite.

[0155] This step is completed jointly by multiple performance monitoring stations (as virtual users) deployed across a wide area and the backend fault location engine to determine the overall quality of PNT service from the perspective of the end user; when the service is abnormal, the root cause satellite or fault link is accurately located through data correlation analysis.

[0156] Based on the same idea, this invention also provides a service message anomaly monitoring system based on a satellite-based augmentation system. The system includes: an augmentation message acquisition module, a static inspection module, a broadcast message acquisition module, a satellite-to-ground consistency comparison module, an OC residual assessment module, a positioning integrity verification module, a database, and a fault association and location module; wherein...

[0157] The enhanced message acquisition module is used to acquire the enhanced message generated by the main control station based on the observation data of the observation station.

[0158] The static check module is used to perform a static check on the enhanced message after it is generated by the ground master control station and before it is injected into the satellite. If the static check passes, uplink injection is allowed; if the static check fails, the fault association and location module is activated.

[0159] The broadcast message acquisition module is used to acquire the enhanced message broadcast by the enhanced information broadcasting satellite;

[0160] The satellite-to-ground consistency comparison module is used to compare satellite-to-ground consistency in real time; if the comparison passes, the OC residual evaluation module is activated; if the comparison fails, the fault association and location module is activated.

[0161] The OC residual assessment module is used to assess the observation quality based on the OC residual to verify the enhancement effect of the enhanced message; if the verification is successful, the positioning integrity check module is activated; if the verification fails, the OC residual is determined to be abnormal, and the fault association and positioning module is activated.

[0162] The positioning integrity verification module is used to deploy several monitoring stations equivalent to user terminals within the enhanced service range, and to perform precise single-point positioning PPP integrity verification based on the monitoring stations; if the verification passes, the service message is normal; if the verification fails, it is determined that the PPP positioning of the monitoring station is abnormal, and the fault association and positioning module is activated.

[0163] The database is used to store rule bases or algorithm models;

[0164] The fault association and location module is used to perform fault association and location based on rule base or algorithm model and judgment results.

[0165] In this embodiment, each module is implemented using a processor, with additional memory added as needed for storage. The processor can be, but is not limited to, a microprocessor (MPU), a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components, etc. The memory can include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory can also be at least one storage device located remotely from the aforementioned processor.

[0166] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0167] It should also be noted that the service message anomaly monitoring system based on satellite-based augmentation system described in this embodiment corresponds to the service message anomaly monitoring method based on satellite-based augmentation system. The description and limitations of the method also apply to the system, and will not be repeated here.

[0168] As can be seen from the above technical solutions, the service message anomaly monitoring method and system based on satellite-based augmentation systems provided in the embodiments of the present invention achieve the following objectives:

[0169] First, an enhanced message end-to-end collaborative monitoring system has been constructed. Existing technologies mostly involve scattered and independent monitoring nodes, while this invention organically links the four key nodes of enhanced message—ground generation, satellite injection, space broadcasting, and user-end application—to form a complete monitoring closed loop. By performing performance prediction and interception before the enhanced message is injected into the satellite, immediately comparing the consistency between the ground and space after satellite broadcasting, and verifying the enhanced service effect at the user end through multi-level positioning, seamless monitoring of the entire lifecycle of differential correction and integrity information—from generation to injection, broadcasting, and application—is achieved. This systematic design fundamentally changes the fragmented nature of traditional monitoring processes, enabling precise backtracking from user-end anomaly location to the source of the fault.

[0170] Second, a dual verification mechanism of "bit-level + positioning-level" was created. This invention goes beyond traditional single data verification. On the one hand, it performs bit-by-bit comparison between the enhanced messages broadcast by satellite and those generated on the ground to accurately detect "hard" faults caused by uplink or on-board storage. On the other hand, it innovatively introduces a verification method based on actual positioning performance, using two different methods, SPP (Standard Point Positioning) and PPP (Precise Point Positioning), to verify the positioning results and comprehensively evaluate the actual effectiveness of the enhanced messages. This dual verification mechanism, combining "data correctness" and "service effectiveness," can detect enhanced service performance degradation problems that traditional methods cannot identify, greatly improving the depth of enhanced service reliability monitoring.

[0171] Third, an intelligent fault location engine based on multi-source information fusion was developed. By correlating and analyzing the monitoring results across the entire link, a fault location engine with logical reasoning rules was constructed, capable of accurately locating faults in links such as the "enhanced information generation system," "satellite uplink injection link," "satellite itself," or "original navigation satellite signals." Based on the reasoning mechanism of multi-source information fusion, intelligent diagnosis of complex enhanced service links was achieved. This reasoning mechanism based on multi-source information fusion transforms the fault diagnosis process, which relies on manual experience, into an automatic, rapid, and accurate intelligent diagnosis, significantly improving system operation and maintenance efficiency and security.

[0172] This invention proposes a method for "enhanced message full-link closed-loop monitoring," which for the first time integrates the generation of differential corrections, calculation of integrity parameters, satellite-to-ground transmission links, and user-end enhancement effect verification—all unique to enhancement services—into a unified system. It establishes a complete quality traceability chain from the source of corrections to the final positioning enhancement effect, breaking through the limitations of traditional single-link monitoring. It constructs a dedicated "ground-satellite-user" full-link collaborative monitoring system for enhancement services. By performing feedforward verification of differential corrections and integrity parameters on the ground, problematic enhancement messages are intercepted at the source, significantly improving the early warning capability of the satellite-based enhancement system and effectively preventing erroneous corrections from affecting user positioning accuracy and integrity. Furthermore, it creates an innovative mechanism of "correction as enhancement effectiveness verification," breaking through the limitations of traditional data verification. Through bit-level consistency comparison and OC residual analysis for rapid verification, and PPP precise verification for dual precision evaluation, it directly verifies the actual enhancement effect of differential corrections and integrity parameters, achieving a fundamental leap from parameter correctness to service effectiveness. The system employs a dual verification mechanism of "bit-level data verification + location-level effect verification." This not only ensures the correctness of enhanced message transmission through bit-level comparison but also directly evaluates the actual enhancement effect of differential corrections through multi-level location verification using OC and PPP, achieving in-depth verification from data integrity to service effectiveness. A dedicated intelligent fault location engine for enhanced services, incorporating multi-source information fusion, has been designed. Addressing the unique characteristics of the enhanced service link, diagnostic rules based on consistency analysis of corrections and integrity parameters such as UDRE / GIVE have been established. This allows for accurate differentiation of enhancement system fault modes such as "abnormal correction generation," "distorted integrity parameters," and "enhanced service failure." By analyzing the consistency between integrity parameters such as UDRE and GIVE and actual errors, the system can accurately diagnose enhancement system-specific faults such as "abnormal correction generation" and "distorted integrity parameters," solving the technical challenge of ambiguous fault location in traditional methods and transforming fault diagnosis, which relies on manual experience, into automated intelligent diagnosis. This invention has significant advantages in enhancing the forward-looking nature of service monitoring, the accuracy of diagnosis, the efficiency of operation and maintenance, and the reliability of the system, providing comprehensive and intelligent quality assurance for satellite-based augmentation services from the generation of correction data to the final positioning effect.

[0173] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for monitoring service message anomalies based on a satellite-based augmentation system, characterized in that, The method includes the following steps: Step S1: Obtain the enhanced message generated by the master control station based on the observation data from the observation station; Step S2: After the enhanced message is generated by the ground master control station and before it is injected into the satellite via uplink, a static check is performed on the enhanced message; If the static check passes, proceed to step S3; If the static check fails, it is determined that there is a static anomaly, and proceed to step S7; Step S3: Upload the enhanced message to the corresponding enhanced information broadcasting satellite, and broadcast the enhanced message by the enhanced information broadcasting satellite; Step S4: Receive the broadcast enhanced message and compare the satellite-to-ground consistency in real time; if the comparison passes, proceed to step S5; if the comparison fails, proceed to step S7. Step S5: Observation quality assessment is performed based on OC residuals to verify the enhancement effect of the enhanced message; If the verification passes, proceed to step S6; if the verification fails, it is determined that the OC residual is abnormal, and proceed to step S7. Step S6: Within the enhanced service range, deploy several monitoring stations equivalent to user terminals, and conduct precise single-point positioning PPP integrity verification based on the monitoring stations; If the inspection passes, the service message is normal; If the test fails, it is determined that the PPP positioning of the monitoring station is abnormal, and proceed to step S7; Step S7: Construct a rule base or algorithm model, and perform fault association and location based on the judgment results.

2. The method according to claim 1, characterized in that, Step S2 performs a static check on the enhanced message, including: Step S21: Check the rationality of the parameters; if the test value of any parameter is negative, it is determined that there is a static anomaly in the current enhanced message; if the test values ​​of all parameters are positive, proceed to step S22. Step S22: Check the consistency between the orbit and clock difference extrapolation; if any value exceeds the alarm threshold range, it is determined that the message does not meet the extrapolation consistency and the current enhanced message has a static anomaly; if all values ​​are within the alarm threshold range, it is determined that the current enhanced message passes the static check and is allowed to be added.

3. The method according to claim 2, characterized in that, Step S22, which involves verifying the consistency between the orbit and clock extrapolation, includes the following steps: Step S221: Calculate the future satellite position sequence after enhancement over a predetermined time period using the broadcast message and the enhanced message to be added. and enhanced satellite clock sequence ; These are the coordinates of the satellite's position in the Earth-fixed coordinate system; Step S222: Obtain the post-hoc precise satellite position sequence of the navigation satellites from the master control station. and precision clock difference sequence As a reference truth value; Step S223: Calculate the orbital error vector based on the enhanced position sequence and the precise position sequence, using the following formula: (3) In equation (3), Represents the orbital error vector. These represent the position differences along the three axes in the Earth-fixed coordinate system; Step S224, convert the orbital error vector Transform from the Earth-fixed coordinate system to the local orbital coordinate system of the satellite along the radial direction R, the track A, and the normal direction C, respectively; Step S225: Based on the enhanced clock error sequence and the precise clock error sequence, calculate the clock error and convert it into an equivalent ranging error. (4) In equation (4), The speed of light; Step S226: Based on the ranging error, the SISRE approximation model for spatial signal ranging error is used for calculation: (5) In equation (5), These represent the components of the broadcast track error in the tangential, normal, and radial directions, respectively. This represents the error in broadcast clock bias, expressed in meters (m). Represents weighting factors. Indicates the distance measurement error; Step S227: Calculate the maximum value, average value and 95th percentile of the ranging error within the preset time period, and compare them with the preset alarm thresholds respectively; if any value exceeds the alarm threshold range, it is determined that the message does not meet the extrapolation consistency; if all values ​​are within the alarm threshold range, it is determined that the message passes the static check and is allowed to be bet.

4. The method according to claim 1, characterized in that, Step S4 involves real-time comparison of satellite-to-ground consistency, including bit-level comparison of the message content, specifically: The monitoring station receiver demodulates and decodes the satellite downlink radio frequency signal to fully recover the enhanced message data block, ensuring the transmission of the enhanced message broadcast by the satellite. This is the data that the receiver considers correct; from the ground control system, the corresponding enhanced messages that should have been uploaded to the satellite are acquired in real time. ; right and Perform time matching and execute the consistency function: (6) In equation (6), Represents a consistency function; If all fields are completely identical, the result is "Match," indicating a match; otherwise, the result is "Mismatch," indicating an anomaly.

5. The method according to claim 1, characterized in that, Step S5 involves evaluating the observation quality based on the OC residuals, including the following steps: Step S51: The pseudorange observation value is obtained directly by the monitoring receiver. ; Step S52, calculate the pseudorange value ; Step S53, calculate the OC residual, using the following formula: (8) In equation (8), The OC residual represents the observed value. Compared with calculated values difference; Step S54, calculate each satellite Residual statistics within a preset time period; Step S55: If the residual statistic or the OC residual of a single epoch exceeds the alarm threshold set based on historical data, it is determined that the satellite broadcast message has a systematic deviation at the physical level.

6. The method according to claim 5, characterized in that, In step S52, the pseudorange is calculated. The formula is as follows: (7) In equation (7), Indicates the satellite's location; This indicates the precisely known coordinates of the monitoring station; Indicates satellite clock bias; Indicates receiver clock bias; These represent the delay corrections for the ionosphere and troposphere, respectively. This represents the relativistic effect correction term.

7. The method according to claim 1, characterized in that, Step S6 involves a PPP location integrity check, the steps of which are as follows: Step S61: Based on the broadcast messages, enhanced messages and observations received by the monitoring station, calculate the PPP and PPP error; Step S62: Preset PPP error threshold for each monitoring station; Determine whether the current monitoring station has a PPP positioning error that continuously exceeds the threshold within a predetermined time period; If it exists, the test is deemed to have failed, and the process proceeds to step S7.

8. The method according to claim 7, characterized in that, The PPP solution formula is as follows: (10) (11) In equations (10) and (11), s and i represent the satellite and signal frequencies, respectively. These represent the pseudorange and carrier phase observations, respectively. Indicates the geometric distance between the user and the satellite; This indicates the broadcast clock error corrected by the enhanced message; Indicates receiver clock bias; These are the delay corrections for the ionosphere and troposphere, respectively. These represent the pseudorange code deviations of the receiver and the satellite, respectively. These represent the phase hardware delays of the receiver and the satellite, respectively. These represent the integer ambiguity of the carrier wavelength and phase observation, respectively; These represent pseudorange and carrier observation noise, respectively. The formula for calculating PPP positioning error is as follows: (12) In equation (12), This represents the calculated coordinates of the receiver in the Earth-fixed coordinate system. This represents the known precise coordinate reference value of the monitoring station.

9. The method according to claim 1, characterized in that, Step S7 involves fault association and location based on the judgment result, including: When a static anomaly is detected in the enhanced message, an enhanced message generation fault alarm is triggered, preventing the message from being uploaded. The fault is located in the ground master control station generation system, and an error analysis report is recorded to allow ground maintenance personnel to investigate potential problems in the master control station's orbit determination and prediction algorithm; this is the result R1. When an anomaly is detected in the real-time comparison of satellite-to-ground consistency, a bit comparison alarm is triggered, the fault is located in the ground uplink injection chain or the satellite's storage / processing unit, and a check of the uplink injection station and onboard data management system is prompted; as result R2; When an OC residual is determined to be abnormal, an OC residual alarm is triggered. The fault is located in the physical deviation of the satellite's signal generation unit. The satellite is marked as unusable or used with reduced accuracy, and its health status is broadcast. This is the result R3. If a single monitoring station is determined to have an abnormal PPP positioning, while its surrounding stations are normal, the positioning fault is due to an issue with the enhanced message precision correction number. The monitoring station is marked as suspicious, but no system-level alarm is triggered; this is the result R4. If at least two monitoring stations are found to have PPP positioning anomalies, it is then determined whether the current satellite's augmentation message anomaly caused the positioning anomaly. Based on the combined results R1, R2, R3, and R4, the fault is located on the ground, uplink, or satellite.

10. A service message anomaly monitoring system based on a satellite-based augmentation system, characterized in that, The system includes: an enhanced message acquisition module, a static inspection module, a broadcast message acquisition module, a satellite-to-ground consistency comparison module, an OC residual assessment module, a positioning integrity verification module, a database, and a fault association and location module; wherein, The enhanced message acquisition module is used to acquire the enhanced message generated by the main control station based on the observation data of the observation station. The static check module is used to perform a static check on the enhanced message after it is generated by the ground master control station and before it is injected into the satellite. If the static check passes, uplink injection is allowed; if the static check fails, the fault association and location module is activated. The broadcast message acquisition module is used to acquire the enhanced message broadcast by the enhanced information broadcasting satellite; The satellite-to-ground consistency comparison module is used to compare satellite-to-ground consistency in real time; if the comparison passes, the OC residual evaluation module is activated; if the comparison fails, the fault association and location module is activated. The OC residual assessment module is used to assess the observation quality based on the OC residual to verify the enhancement effect of the enhanced message; if the verification is successful, the positioning integrity check module is activated; if the verification fails, the OC residual is determined to be abnormal, and the fault association and positioning module is activated. The positioning integrity verification module is used to deploy several monitoring stations equivalent to user terminals within the enhanced service range, and to perform precise single-point positioning PPP integrity verification based on the monitoring stations; if the verification passes, the service message is normal; if the verification fails, it is determined that the PPP positioning of the monitoring station is abnormal, and the fault association and positioning module is activated. The database is used to store rule bases or algorithm models; The fault association and location module is used to perform fault association and location based on rule base or algorithm model and judgment results.

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