A multi-source pilot navigation information fusion method and system based on space-time features

Abstract

The application provides a kind of multi-source pilot navigation information fusion method and system based on space-time characteristics.The method comprises the following steps: obtaining pilot navigation data from different pilot navigation systems and data sources;classifying the data with normal judgment results according to information type;conducting rationality test on the classified pilot navigation data;conducting space-time consistency calibration on multi-source heterogeneous homogeneous data that pass the rationality test;conducting data fusion on the multi-source heterogeneous homogeneous data that pass the consistency calibration;conducting integrity evaluation on the fused pilot navigation data;formatting distribution and storage according to different maritime business pilot navigation requirements;providing the integrated pilot navigation service platform with the fused pilot navigation data labeled with integrity level.The application can provide the integrated pilot navigation system with pilot navigation data labeled with integrity level, provide a unified regulatory basis for managers, ensure ship navigation safety, and comprehensively support maritime traffic organization and precise space-time maritime services.

Description

Technical Field

[0001] This invention relates to the field of maritime navigation aids technology, and more particularly to a method and system for multi-source navigation aids information fusion based on spatiotemporal characteristics. Background Technology

[0002] Maritime navigation aids information is fundamental data for ensuring ship navigation safety and organizing and managing maritime traffic. With the continuous emergence and development of various new navigation aid technologies, such as the VHF Data Exchange System (VDES) and Maritime Digital Broadcasting (NAVDAT), navigation aid systems and services have been further supplemented and improved. However, because existing navigation aid systems are independent and lack a fusion and coordination mechanism, it is difficult to integrate various navigation aid information, seriously affecting the accuracy of port and coastal navigation aid services, and also hindering timely response to deep-sea navigation aid needs. Therefore, building a highly reliable integrated navigation aid service support system not only aligns with the development direction of e-navigation and coastal-based integrated management, but is also an inevitable trend for future maritime services. Spatiotemporally unified, benchmark-consistent, and highly reliable navigation aid information is the cornerstone of building an integrated navigation aid service support system and a prerequisite for providing high-quality integrated navigation aid services.

[0003] However, current navigation aid information comes from different navigation aid systems and external data sources. Due to the asynchronous time and different data benchmarks of various navigation aid systems, there are problems such as inconsistent time and space of navigation aid information, and even conflicts between them. It is difficult to provide highly reliable and unified comprehensive navigation aid services for ship navigation and safety supervision. Summary of the Invention

[0004] This invention provides a multi-source navigation aid information fusion method and system based on spatiotemporal characteristics to overcome the technical problems of inconsistent and conflicting navigation aid information caused by time asynchrony and different data benchmarks of data from different sources in the existing technology, and to provide highly reliable spatiotemporally unified navigation aid data for integrated navigation aid services.

[0005] The technical means employed in this invention are as follows:

[0006] A multi-source navigation aid information fusion method based on spatiotemporal characteristics includes the following steps:

[0007] Acquire navigation data from different navigation aid systems and data sources, parse the acquired navigation data, and determine whether the parsed navigation data is normal;

[0008] Data with normal judgment results are classified according to information type;

[0009] The rationality of the classified navigation aid data is checked, including checking the range of data values ​​and the validity of the effective time.

[0010] Spatial and temporal consistency calibration is performed on multi-source heterogeneous similar data that have passed the rationality test;

[0011] Data fusion is performed on multi-source heterogeneous data of the same type that have passed consistency calibration to generate fused navigation aid data;

[0012] The integrity of the fused navigation data is assessed, and the integrity level is calculated based on the preset integrity index parameters. The navigation data that meets the needs of different users is then output in combination with the preset data integrity level evaluation criteria.

[0013] To meet the diverse navigational aid needs of different maritime operations, navigational aid data that meets user requirements is formatted, distributed, and stored on demand, providing integrated navigational aid data with integrity levels marked for the comprehensive navigational aid service platform.

[0014] Furthermore, data with normal judgment results are classified according to information type, including: ship-related information, route-related information, navigation safety-related information, and hydrological and meteorological-related information.

[0015] Furthermore, the rationality of the classified navigation aid data is tested, including by monitoring the mean and variance within the sliding time window.

[0016] Furthermore, the method also includes: in the process of multi-source navigation aid information fusion processing, performing data alarm processing on the received alarm information, classifying and categorizing the alarm information, and managing the alarm status based on feedback from the integrated navigation aid service platform.

[0017] Furthermore, during the multi-source navigation aid information fusion processing, the received alarm information needs to be processed as a data alarm, including at least one of the following:

[0018] Issue data alarms for navigation aid data with abnormal judgment results;

[0019] Issue data alerts for multi-source heterogeneous similar data that fail the rationality test;

[0020] Data alerts are issued for multi-source heterogeneous data of the same type that fail consistency calibration;

[0021] Data alerts are issued for multi-source heterogeneous similar data that fail the integrity assessment.

[0022] This invention also provides a multi-source navigation aid information fusion system based on spatiotemporal characteristics, comprising:

[0023] The multi-source navigation aid data acquisition unit is used to acquire navigation aid data from different navigation aid systems and data sources, parse the acquired navigation aid data, and determine whether the parsed navigation aid data is normal.

[0024] The classification processing unit is used to classify data with normal judgment results according to information type;

[0025] The rationality verification unit is used to verify the rationality of the classified navigation aid data, including verifying the range of data values ​​and the validity of the effective time.

[0026] The consistency calibration unit is used to perform spatial and temporal consistency calibration on multi-source heterogeneous homogeneous data that has passed the rationality test;

[0027] The data fusion unit is used to fuse multi-source heterogeneous data of the same type that have passed consistency calibration, thereby generating fused navigation aid data;

[0028] The integrity assessment unit is used to assess the integrity of the fused navigation aid data. Based on the preset integrity index parameters, it calculates the integrity level and outputs navigation aid data that meets the needs of different users by combining the preset data integrity level evaluation standards.

[0029] The navigation aid data output unit is used to distribute and store navigation aid data that meets user needs in a formatted manner on demand, in response to different maritime business navigation aid requirements. It provides integrated navigation aid data marked with integrity level to the comprehensive navigation aid service platform.

[0030] Furthermore, the system also includes a data warning unit, which is used to perform data alarm processing on received alarm information during the multi-source navigation aid information fusion processing, classify and categorize alarm information, and manage alarm status based on feedback from the integrated navigation aid service platform.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] This invention relies on existing navigation aid systems and other external data sources. Based on the spatiotemporal characteristics of multi-source heterogeneous navigation aid data, it achieves navigation aid information fusion on the basis of spatiotemporal consistency calibration. It can provide navigation aid data marked with integrity level for the integrated navigation aid service platform, provide managers with a unified regulatory basis, ensure the safety of ship navigation, and fully support maritime traffic organization and precise spatiotemporal maritime services. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart of the multi-source navigation aid information fusion method based on spatiotemporal features of the present invention.

[0035] Figure 2 This is a block diagram of the multi-source navigation aid information fusion system based on spatiotemporal characteristics according to the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] like Figure 1 As shown, this invention provides a multi-source navigation aid information fusion method based on spatiotemporal features, comprising the following steps:

[0038] S1. Obtain navigation data from different navigation systems and data sources, parse the obtained navigation data, and determine whether the parsed navigation data is normal.

[0039] Specifically, this step mainly receives various navigation aid data from different external navigation aid systems and other external data sources. These external navigation aid systems include RBN-DGNSS systems, maritime CORS systems, AIS systems, Navtex systems, etc.; other external data sources include ship registration databases, navigation mark databases, navigation environment databases, electronic charts, etc.; the navigation aid data provided by different navigation aid systems includes various message information sent by the system and system operation status monitoring information. If the parsed navigation aid message information and system operation status monitoring information are normal, proceed to S2. If the parsed navigation aid data contains anomalies, such as message data length not meeting requirements, message data verification errors, or system operation status alarms, proceed to S8.

[0040] S2. Classify the data whose judgment results are normal according to information type.

[0041] Specifically, the input navigation aid data is categorized according to information type, including ship-related information, route-related information, navigation safety-related information, and hydro-meteorological information. Ship-related information can be further subdivided into static ship information, dynamic ship information, and ship voyage information; route-related information can be further subdivided into navigation mark information, waterway information, and obstruction information; navigation safety-related information can be further subdivided into navigation warnings and navigation mark dynamics; and hydro-meteorological information can be further subdivided into real-time hydrological information, forecast hydrological information, real-time meteorological information, and forecast meteorological information.

[0042] S3. Conduct a rationality test on the classified navigation aid data, including testing the range of data values ​​and the validity of the effective time of action.

[0043] Specifically, the rationality of various types of navigation aid data after classification is checked, including the range of data values ​​and the validity of the effective time. Rationality can also be judged by monitoring the mean and variance. It is necessary to determine whether the range of values ​​for various types of navigation aid data is reasonable, such as whether longitude data in spatial information is between -90° and 90°, and whether latitude data in spatial information is between -180° and 180°. For time-sensitive navigation aid data, such as navigation warnings, it is necessary to determine whether they are still within their effective time frame. For time-dependent data, such as ship dynamics data, hydrological data, and meteorological data, their rationality is judged by monitoring whether the mean and variance within their sliding time window exceed thresholds. If the data passes the rationality check, the corresponding navigation aid data is transferred to S4; if the data fails the rationality check, the data source corresponding to this type of data and the reasons for failing the rationality check are transferred to S8.

[0044] S4. Perform spatial and temporal consistency calibration on multi-source heterogeneous data of the same type that have passed the rationality test.

[0045] Specifically, it is preferable to calibrate all spatiotemporal navigation aids data to the coordinate and time systems of the BeiDou Navigation Satellite System, i.e., using the BeiDou coordinate system for spatial information and BeiDou time for time information. The spatiotemporal consistency of the data is compared by combining the temporal and spatial characteristics of similar data from multiple heterogeneous sources. If the data is within a predetermined threshold, it passes consistency calibration and proceeds to S5. If it exceeds the predetermined threshold, the data fails consistency calibration and is excluded in subsequent fusion processing. The data source corresponding to this type of data, the reason for failing consistency calibration, etc., are then transferred to S8.

[0046] S5. Perform data fusion on multi-source heterogeneous data of the same type that have passed consistency calibration to generate fused navigation aid data.

[0047] Specifically, the fusion of multi-source heterogeneous navigation aid data can be achieved using different data fusion algorithms such as adaptive weighted averaging, α-β filtering estimation, Kalman filtering estimation, and Bayesian estimation, and the fused navigation aid data can be output to S6.

[0048] S6. Conduct an integrity assessment on the fused navigation data, calculate the integrity level based on the preset integrity index parameters, and output navigation data that meets the needs of different users by combining the preset data integrity level evaluation standards.

[0049] Specifically, the integrity of the fused navigation aid data is assessed, and the integrity level is calculated based on pre-set integrity index parameters. These parameters include alarm limits, alarm time, and integrity risks, which can be manually set in advance based on experience or automatically calculated based on prior data. The integrity level of the fused navigation aid data is divided into four levels: high, medium, low, and none. If the data integrity level is high or medium, proceed to S7. If the data integrity level is low or none, transfer the fused data and its corresponding integrity level to S8.

[0050] S7. To meet the navigation aid needs of different maritime operations, the navigation aid data that meets the user's needs is formatted, distributed and stored as needed, providing the integrated navigation aid service platform with integrated navigation aid data marked with integrity level.

[0051] Specifically, to meet the diverse navigation aid needs of different maritime operations, the integrated navigation aid data, labeled with integrity assessment information, is formatted, distributed, and stored as needed, providing the integrated navigation aid service platform with integrated navigation aid data labeled with integrity levels. For example, for vessel entry and exit operations, high-precision vessel dynamic position data with high integrity levels can be provided; for deep-sea vessel monitoring operations, general vessel dynamic position data with medium integrity levels can be provided.

[0052] Furthermore, the method also includes:

[0053] S8. During the multi-source navigation aid information fusion processing, received alarm information undergoes data alarm processing, alarm information is classified and categorized, and alarm status is managed based on feedback from the integrated navigation aid service platform. Furthermore, during the multi-source navigation aid information fusion processing, received alarm information requires data alarm processing, including at least one of the following:

[0054] a. Issue data alarms for navigation aid data with abnormal judgment results;

[0055] b. Issue data alerts for multi-source heterogeneous similar data that fails the rationality test;

[0056] c. Issue data alerts for multi-source heterogeneous similar data that fail consistency calibration;

[0057] d. Issue data alerts for multi-source heterogeneous similar data that fail the integrity assessment.

[0058] Specifically, in the process of multi-source navigation aid information fusion processing, received alarm information needs to be processed as data alarms, and the alarm information needs to be classified and categorized. For alarms reported by various navigation aid systems from the S1 parsing and processing output, the alarm source is a data parsing alarm, which is directly forwarded to the integrated navigation aid service platform after classification and grading. During the S3 data rationality check, S4 data consistency calibration, and S6 data integrity assessment processes, if any data anomalies are found, the alarm-related data needs to be analyzed and processed, the alarms are classified and grading according to their source, and then output to the integrated navigation aid service platform. Alarm sources can be divided into rationality alarms, consistency alarms, integrity alarms, etc.; according to information source, they can be divided into ship position, safety information, system, etc.; according to alarm severity, they can be divided into alarms, warnings, alerts, etc. Alarms need to be processed immediately, alarms will evolve into warnings if not further processed, and alerts are information that needs attention. The above levels can be converted to each other. The alarm status is managed based on feedback from the integrated navigation service platform, including alarms that have not been confirmed as activated, alarms that have been confirmed as activated, alarms that have been adjusted for activation, and alarms that have been canceled.

[0059] This invention also discloses a multi-source navigation aid information fusion system based on spatiotemporal characteristics, comprising: a multi-source navigation aid data acquisition unit, a classification and processing unit, a rationality verification unit, a consistency calibration unit, a data fusion unit, an integrity assessment unit, a navigation aid data output unit, and a data warning unit. Specifically:

[0060] The multi-source navigation aid data acquisition unit is used to acquire navigation aid data from different navigation aid systems and other external data sources, parse the acquired data, and determine whether the parsed navigation aid data is normal. External navigation aid systems include the RBN-DGNSS system, maritime CORS system, AIS system, Navtex system, etc.; other external data sources include ship registration databases, navigation mark databases, navigation environment databases, electronic charts, etc. The input data is parsed and processed according to the corresponding data format standards based on the data source. For example, the RBN-DGNSS system follows the RTCMSC10402.3 standard format, and the AIS system follows the IEC 62320-2 standard format.

[0061] The classification processing unit is used to categorize data with normal judgment results according to information type. Specifically, it includes four main categories: ship-related information, route-related information, navigation safety-related information, and hydro-meteorological information. Each main category can be further subdivided into smaller categories. Ship-related information can be further subdivided into ship static information, ship dynamic information, and ship voyage information; route-related information can be further subdivided into navigation mark information, waterway information, and obstruction information; navigation safety-related information can be further subdivided into navigation warnings and navigation mark dynamics; and hydro-meteorological information can be further subdivided into real-time hydrological information, forecast hydrological information, real-time meteorological information, and forecast meteorological information.

[0062] The rationality verification unit is used to verify the rationality of the classified navigation aid data, including the data value range and the validity of the application time. It can also make a rationality judgment by monitoring the mean and variance within the sliding time window. If the data passes the rationality verification, this type of data is output to the data consistency calibration unit; if the data fails the rationality verification, this type of data and the reason for failing the rationality verification are output to the data alarm processing unit.

[0063] The consistency calibration unit is used to perform spatial and temporal consistency calibration on multi-source heterogeneous data of the same type that has passed the rationality check. Specifically, firstly, all spatiotemporal navigation aids are calibrated to the spatiotemporal reference of the BeiDou Navigation Satellite System, that is, spatial information adopts the BeiDou coordinate system, and time information adopts BeiDou time. Then, by comparing the temporal and spatial characteristics of multi-source heterogeneous data of the same type, the various navigation aids processed by the data rationality check unit are subjected to data consistency calibration under the same spatiotemporal reference, supporting verification and fault tolerance among data of the same type. If the data passes the consistency calibration, this type of data is output to the multi-source heterogeneous data fusion unit; if the data fails the consistency calibration, it is excluded in the subsequent processing of the multi-source heterogeneous data fusion unit, and the data source corresponding to this type of data, the reason for failing the consistency calibration, etc., are output to the data alarm processing unit.

[0064] The data fusion unit is used to fuse multi-source heterogeneous data of the same type that have passed consistency calibration, thereby generating fused navigation aid data. Specifically, algorithms such as adaptive weighted averaging, α-β filtering estimation, Kalman filtering estimation, and Bayesian estimation can be used to generate fused navigation aid data.

[0065] The integrity assessment unit evaluates the integrity of the fused navigation aid data. Based on preset integrity index parameters, it calculates the integrity level and outputs navigation aid data that meets the needs of different users, combined with preset data integrity level evaluation standards. Specifically, using pre-set manually or automatically configured integrity index parameters, such as alarm limits, alarm times, and integrity risks, it assesses the integrity of the integrated navigation aid data processed by the multi-source heterogeneous data fusion unit and labels it with integrity levels, such as high, medium, low, and none. If the assessed data integrity level is low or none, and does not meet user needs, the fused data and its corresponding integrity level are output to the data alarm processing unit for processing. If the assessed data integrity level is high or medium, and meets user needs, the fused navigation aid data labeled with integrity assessment information is output to the navigation aid data output unit.

[0066] The navigation aid data output unit is used to format, distribute, and store navigation aid data that meets user needs on demand, based on different maritime business navigation aid requirements. It provides the integrated navigation aid service platform with fused navigation aid data marked with integrity levels. Specifically, according to the different needs of coastal, port, and deep-sea maritime business navigation aid services, the integrated navigation aid data marked with integrity levels is formatted, distributed, and stored for use by different maritime businesses of the integrated navigation aid service platform.

[0067] Furthermore, the system also includes a data warning unit, which is used to process received alarm information during the multi-source navigation aid information fusion processing, classify and categorize alarm information, and manage alarm status based on feedback from the integrated navigation aid service platform. Specifically, this unit processes various alarm information detected by other units, classifies and categorizes alarms, alerts maritime regulatory personnel through the integrated navigation aid service platform, and sets alarm status based on feedback from maritime regulatory personnel. For alarms reported by various navigation aid systems output by the multi-source navigation aid data acquisition unit, they are classified and directly forwarded to the integrated navigation aid service platform. During data rationality verification, data consistency calibration, and data integrity assessment, if any data anomalies are found, the data alarm processing unit analyzes and processes the alarms, classifies and categorizes them according to their source, and outputs them to the integrated navigation aid service platform.

[0068] The data warning unit includes alarm states such as: unconfirmed activation, confirmed activation, adjusted activation, and canceled. Alarm sources include: data parsing alarms, reasonableness alarms, consistency alarms, and integrity alarms. Alarm levels include: alerts, warnings, and alerts, and these levels can be converted between each other. Alarm categories include: ship position alarms, safety information alarms, and system alarms.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-source navigation aid information fusion method based on spatiotemporal characteristics, characterized in that, Includes the following steps: The system acquires navigation aid data from different navigation aid systems and data sources, parses the acquired navigation aid data, and determines whether the parsed navigation aid data is normal. The navigation aid systems include the RBN-DGNSS system, the maritime CORS system, the AIS system, and the Navtex system. The data sources include ship registration databases, navigation mark databases, navigation environment databases, and electronic nautical charts. Data with normal judgment results are classified according to information type; information types include ship-related information, route-related information, navigation safety-related information, and hydro-meteorological-related information. Ship-related information includes ship static information, ship dynamic information, and ship voyage information. Route-related information includes navigation mark information, waterway information, and obstruction information. Navigation safety-related information includes navigation warnings and navigation mark dynamics. Hydro-meteorological-related information includes real-time hydrological information, forecast hydrological information, real-time meteorological information, and forecast meteorological information. The rationality of the classified navigation aid data is checked, including checking the range of data values ​​and the validity of the effective time. Spatial and temporal consistency calibration is performed on multi-source heterogeneous similar data that have passed the rationality test; Data fusion is performed on multi-source heterogeneous data of the same type that have passed consistency calibration to generate fused navigation aid data; The integrity of the fused navigation data is assessed, and the integrity level is calculated based on the preset integrity index parameters. The navigation data that meets the needs of different users is then output in combination with the preset data integrity level evaluation criteria. To meet the navigation assistance needs of different maritime operations, navigation assistance data that meets user needs is formatted, distributed, and stored on demand, providing integrated navigation assistance data with integrity levels marked for the comprehensive navigation assistance service platform; In the process of multi-source navigation aid information fusion processing, received alarm information is processed as a data alarm, and the alarm information is classified and categorized. The alarm status is managed based on feedback from the integrated navigation aid service platform. In the process of multi-source navigation aid information fusion processing, received alarm information must be processed as a data alarm, including at least one of the following: Issue data alarms for navigation aid data with abnormal judgment results. Data alerts will be issued for multi-source, heterogeneous, and similar data that fail the reasonableness test. Data alerts are issued for multi-source heterogeneous data of the same type that fail consistency calibration. Data alerts are issued for multi-source heterogeneous similar data that fail the integrity assessment.

2. The multi-source navigation aid information fusion method based on spatiotemporal characteristics according to claim 1, characterized in that, The rationality of the classified navigation aid data is verified, including by monitoring the mean and variance within the sliding time window.

3. A multi-source navigation aid information fusion system based on spatiotemporal characteristics, used to implement the method as described in claim 1 or 2, characterized in that, include: A multi-source navigation aid data acquisition unit is used to acquire navigation aid data from different navigation aid systems and data sources, parse the acquired navigation aid data, and determine whether the parsed navigation aid data is normal. The navigation aid systems include RBN-DGNSS system, maritime CORS system, AIS system, and Navtex system. The data sources include ship registration database, navigation mark database, navigation environment database, and electronic nautical charts. The classification and processing unit is used to classify data with normal judgment results according to information type. Information types include ship-related information, route-related information, navigation safety-related information, and hydro-meteorological-related information. Ship-related information includes ship static information, ship dynamic information, and ship voyage information. Route-related information includes navigation mark information, waterway information, and obstruction information. Navigation safety-related information includes navigation warnings and navigation mark dynamics. Hydro-meteorological-related information includes real-time hydrological information, forecast hydrological information, real-time meteorological information, and forecast meteorological information. The rationality verification unit is used to verify the rationality of the classified navigation aid data, including verifying the range of data values ​​and the validity of the effective time. The consistency calibration unit is used to perform spatial and temporal consistency calibration on multi-source heterogeneous homogeneous data that has passed the rationality test; The data fusion unit is used to fuse multi-source heterogeneous data of the same type that have passed consistency calibration, thereby generating fused navigation aid data; The integrity assessment unit is used to assess the integrity of the fused navigation aid data. Based on the preset integrity index parameters, it calculates the integrity level and outputs navigation aid data that meets the needs of different users by combining the preset data integrity level evaluation standards. The navigation aid data output unit is used to distribute and store navigation aid data that meets user needs in a formatted manner on demand, in order to meet different maritime business navigation aid requirements. It provides the integrated navigation aid service platform with integrated navigation aid data marked with integrity level. The data warning unit is used to process received alarm information during the multi-source navigation aid information fusion processing, classify and categorize the alarm information, and manage the alarm status based on feedback from the integrated navigation aid service platform; wherein the data alarm processing includes at least one of the following: Issue data alarms for navigation aid data with abnormal judgment results. Data alerts will be issued for multi-source, heterogeneous, and similar data that fail the reasonableness test. Data alerts are issued for multi-source heterogeneous data of the same type that fail consistency calibration. Data alerts are issued for multi-source heterogeneous similar data that fail the integrity assessment.

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