SESAR WP8 Early Project 2 MET Data Fusion Demonstrator

Transcription

1 EUROPEAN ORGANISATION FOR THE SAFETY OF AIR NAVIGATION SESAR WP8 Early Project 2 MET Data Fusion Demonstrator In support of Weather Assimilated ATM Decision Making Edition Number : 1.0 Edition Date : 24 June 2009 Status : Final Intended for : General Public

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3 DOCUMENT APPROVAL The following table identifies all management authorities who have successively approved the present issue of this document. AUTHORITY NAME SIGNATURE DATE Document Author D. Hart 24 June 09 Agency WP leader S. Van Der Stricht 24 June 09 Sesar Contribution manager J. Derisson 24 June 09 Edition: Error! Reference source not found.error! Reference source not found. Page 1

4 DOCUMENT CHANGE RECORD The following table records the complete history of the successive editions of the present document. EDITION NUMBER EDITION DATE REASON FOR CHANGE PAGES AFFECTED Internal EUROCONTROL review All nd internal EUROCONTROL review All Publications EUROCONTROL Headquarters 96 Rue de la Fusée B-1130 BRUSSELS Tel: +32 (0) Fax: +32 (0) publications@eurocontrol.int Page 2 Error! Reference source not found. Edition: Error! Reference source not found.

5 Contents DOCUMENT APPROVAL...1 DOCUMENT CHANGE RECORD...2 EXECUTIVE SUMMARY...4 CHAPTER 1 Introduction Context Aviation Meteorology The Challenge...5 CHAPTER 2 The Demonstrator General Standards and Principles Data Models for Weather Information GML OGC Web Services Architecture Data Sources Data Types, Formats and Conversion Initial Conversion Capability...14 CHAPTER 3 The Demonstration Findings Demonstrator Implementation Follow-Up Activities Recommendations Data modelling: WXCM and WXXM modifications evolution of Demonstrator...20 CHAPTER 4 Conclusions...21 ANNEX 1 Service Oriented Approach...22 ANNEX 2 OGC...24 ANNEX 3 WXCM/WXXM modifications...26 Edition: Error! Reference source not found.error! Reference source not found. Page 3

6 EXECUTIVE SUMMARY Meteorological information is a key conditioner for air transport. Having knowledge about the past, current and future state of the atmosphere is an essential prerequisite to make the foreseen ATM Master Plan concepts such as Integration of Airport turn-around operations, Time and performance based operations (4D Trajectories), Rolling Network Operations Plan, Automation support to the Human and Efficient separation modes work and perform in daily life. The MET Data Fusion Demonstrator is the instantiation of the WXXM SESAR WP8 Early Project. This project is an initial demonstration of how the geospatial and time enabled provision of meteorological information in the ATM System, as foreseen by the European ATM Master Plan, could be implemented by applying an open and transparent Meteorological Information Exchange Model (WXXM) based on Industry standards. The concepts, architecture and standards used for the exchange of meteorological information are an example of how to apply a Service Oriented Approach for the meteorological service provision domain. For the demonstrator, existing open standards and best practices developed within the International Standardisation Organisation (ISO) and Open Geospatial Consortium (OGC) were successfully used and are one option for the required move from proprietary ATM or MET specific services, interfaces and formats as foreseen by the European ATM Master Plan. Whilst the focus of the demonstration is on testing the current capability of the WXXM, the demonstration also provides an initial insight in how Meteorological Information Services could look like and could be used to make the ATM System more predictable. Page 4 Error! Reference source not found. Edition: Error! Reference source not found.

7 CHAPTER 1 Introduction 1.1 Context The MET Data Fusion Demonstrator is the instantiation of the WXXM SESAR WP8 Early Project. This document provides an overview, concept, findings and recommendations of the MET Data Fusion Demonstrator project. This project is a demonstration of the provision of meteorological information in the time, trajectory and performance based ATM System as foreseen by the European ATM Master Plan by applying a meteorological information exchange model based on open Industry standards, the WXXM. 1.2 Aviation Meteorology Meteorological information is the key conditioner for air transport. Having knowledge about the past, current and future state of the atmosphere is an essential prerequisite to make the foreseen concepts such as Integration of Airport turn-around operations, Time and performance based operations (4D Trajectories), Rolling Network Operations Plan, Automation support to the Human and Efficient separation modes work and perform in daily life. Where today s focus of meteorological information provision is mainly on hazard prevention for flight crews, integrating weather information into the relevant ATM decision making processes and to seriously improve the ATM System performance and robustness is not yet explored to the maximum possible extent. In the time-ordered ATM system, precise knowledge about the weather conditions that could impact an individual flight trajectory, airport operations or the network operations as a whole is essential. 1.3 The Challenge To reach this state of Weather Assimilated Decision Making requires the integration of weather information in decision support methodologies and the supporting systems. Service orientation, a Service Oriented Approach (SOA), uncoupling the provision and the use of the Edition: Error! Reference source not found.error! Reference source not found. Page 5

8 information, could be an important step in the evolution of the meteorological component of ATM. Annex 1 provides some background information on SOA. Not only would the today s required meteorological information be opened up for the stakeholders who have a need but have no means to access the information. It also introduces a level of flexibility on both provider and user side to come up with new requirements and capabilities that could easily be made part of the intranet of ATM. In other words, SOA would provide the framework to ensure the connectivity between foreseen and unforeseen aviation meteorological information providers and users in exchanging foreseen and unforeseen shared aviation meteorological information. To achieve this connectivity, this interchange of meteorological information is seen as a key component for the success of SESAR. The MET Data Fusion Demonstrator is an early demonstration of this required capability with the main intent to test the required Meteorological Information Exchange Model (WXXM), its overarching Meteorological Information Conceptual Model (WXCM) and in the case of this project the XML (GML) instantiation in the form of an XML Schema. Chapter 2 provides detailed information about the data models and schemas used in the demonstration. For illustration purposes, figure 1-1 provides an example of today s connectivity whilst figure 1-2 demonstrates the future interchange of information inclusive of meteorological information as foreseen by the European ATM Master Plan. Figure 1-1 Example of existing interconnections for MET information Page 6 Error! Reference source not found. Edition: Error! Reference source not found.

9 Figure 1-2 Connecting the Information and the Users Edition: Error! Reference source not found.error! Reference source not found. Page 7

10 CHAPTER 2 The Demonstrator 2.1 General The aim of the demonstrator is to demonstrate a possible concept for the provision of meteorological information in the time, trajectory and performance based ATM System as foreseen by the European ATM Master Plan by applying a meteorological information exchange model based on open Industry standards, the WXXM. Moreover, to test the existing version of WXXM and supporting data models. At a secondary level, it also demonstrates a concept of meteorological information sharing and data fusion beyond its current utilisation in a conventional product centric -stove pipedmanner by applying this open and transparent means of exchange. The targeted meteorological information for the demonstrator is exchanged by open and transparent means, the WXXM version 1.0.1, and is made available by means of Open Geospatial Consortium (OGC) web services to demonstrate possible fusion of spatial and temporal information for end user applicability; a description of OGC is attached as Annex 2. This objective requires standardised data exchange format and interfaces, ready to be used by external systems in accordance with SOA; this allows data to be shared and accessed by any system with the required capability and credentials. The demonstrator also focuses on the geo-spatial dimension of the information; filtering the information based on time, altitude and position. This will increase the data usability and prevent information overloading. Another dimension of the demonstrator is its use of meteorological information currently unknown to the international ATM community. Whilst an important component of the demonstrator is to demonstrate the exchange of ICAO Annex 3 type of information with the help of mainstream IT solutions and based on open industry standards; to demonstrate that currently available met information beyond what is currently required by ICAO Annex3 could be utilised for ATM, is the other paramount theme. Excluded from the demonstrator project is the ability or capability to ingest, convert or serve other data than meteorological data for data fusion purposes. For the demonstrator it is assumed that relevant other data types and sources and relevant linked OGC web services are available to demonstrate fusion, for instance by the interrelated WP14 D-AIM early project. Page 8 Error! Reference source not found. Edition: Error! Reference source not found.

11 Figure 2-1 Conceptual Overview Demonstrator 2.2 Standards and Principles Data Models for Weather Information In line with the main stream industry concepts and philosophy on data modelling, the process of MET data modelling initialised within EUROCONTROL identifies 3 levels: 1. Conceptual level for defining a conceptual model 2. Logical level to define the exchange model 3. Physical level for data exchange Since the physical layer is related to specific technology and hardware, only the conceptual and logical models have been defined. To encourage the use of the MET data model for the exchange of weather information in the ATM domain, a GML 1 compliant XML 2 -schema has been developed based on the exchange model WXCM Weather Information Conceptual Model (WXCM) is the conceptual model for MET data, following the described modelling concept by applying industry standards and principles and whilst providing compatibility/interoperability with the existing ICAO structures, types and formats of MET messages. The WXCM has the following high-level characteristics: Data centric Clear separation of concern between provision, exchange and use of data Clear packaging of model in three tiers o o Tier 1: Base Layer; universally applicable ISO data types and geometry Core measures and units Tier 2: Domain Layer; specific to MET Domain-specific data types and geometry 1 GML: Geography Markup Language 2 XML: Extensible Markup Language Edition: Error! Reference source not found.error! Reference source not found. Page 9

12 o Observations & forecasts Weather phenomena Tier 3: Products & Services Layer Described in the Unified Modeling Language (UML) WXXM and WXXS The Weather Information Exchange Model (WXXM) serves as the exchange model for MET data. Generated from WXCM, WXXM provides a structure to express meteorological features technology independent ; in UML. The main components of WXXM are features that contains Fixed items (volcanoes, airports, radars, sensors,..) General attributes (localisation,..) Specific attributes (height, ICAO code, name,.. Observations that are variable elements (e.g. winds, temperatures, VA clouds, ) with general attributes (observation time, targets) and specific attributes (speed, direction, degree of turbulence,..) Forecasts with the same structure as observations plus a forecast time Implementations of WXXM in XML (GML) will follow a defined schema, the Weather Information Exchange Schema (WXXS). This GML extension WXXM schema defines a XML structure to express meteorological features GML Created by OGC, adopted by ISO and based on XML specifications, the Geography Markup Language is used to describe geographical objects. It serves as a modelling language for geographic systems as well as an open interchange for geographic transactions on the Internet. Note that the concept of feature in GML is a very general one and includes not only conventional "vector" or discrete objects, but also coverage and sensor data. GML defines features distinct from geometry objects; a feature represents a physical entity and geometry defines a location or an area; a GML feature can have various geometry properties that describe geometric aspects OGC Web Services Within the broader context of Web Services, OGC Web Services (OWS) represent an evolutionary, standards-based framework that enables seamless integration of a variety of online geo-processing and location services. OWS allows distributed geo-processing systems to communicate with each other across the Web using familiar technologies such as XML and HTTP. OGC Web Services provide a vendor-neutral, interoperable framework for web-based discovery, access, integration, analysis, exploitation and visualization of multiple online geo data sources, sensor-derived information, and geo-processing capabilities. OWS can be a framework for building network-connected geo-processing applications or for integrating geo-processing capability into other information applications. In this manner, OWS is a web of geo-processing services that can be connected in dynamic, open interoperable chains to create dynamic applications. OWS are self-contained, self-describing, modular applications that can be published, located, and invoked across the Web. An OGC Web Service can thus be treated as a black box Operations) that performs a task. Since an OGC Web Service can describe the operation or operations they perform in Metadata (Capabilities), it is possible to search for services and understand what operations a given web accessible service can perform. These web Page 10 Error! Reference source not found. Edition: Error! Reference source not found.

13 services are addressable by a URL and are by definition network accessible. The OWS framework allows multiple services to be connected in sequence while at the same time allowing them to keep internal business logic independent and if need be, proprietary. The following figure provides a general architectural schema for OWS. This schema identifies the generic classes of services that participate in various geo-processing and location activities. Further, it identifies the properties that the services in those classes must have to connect them into useful applications. Figure 2-2 OGC Web Services General Architecture The vision for OGC Web Services is influenced by many factors: 1. The need to support many independently developed implementations of a given service, such as the ability to relate information to a 4D-Business Trajectory; 2. The need to be able to chain services together to build an application; 3. The need to support many independently provided instantiations of the services; 4. The need to find specific instantiations of the services based on service type, service content, and service characteristics or quality factors; 5. The need to enable access control, security, and e-commerce on the services; 6. A desire to enable ad-hoc chaining of services to satisfy aggregated workflow processes. The project is focused on data instead of business services. Therefore, this document will be about exposure of specific MET information rather than ATM services. 2.3 Architecture The MET Data Fusion Demonstrator is a Web application written in JAVA and based on technologies like Struts, Java Server Page and XMLBeans. The application collects and converts different meteorological data file types in one specific type, the Weather Information Exchange Model (WXXM) data type. The data is stored and served as an OGC web service. Figure 2-3 illustrates the chosen architecture for the demonstrator. Edition: Error! Reference source not found.error! Reference source not found. Page 11

14 Figure 2-3 Architecture The demonstrator covers the following steps: 1. Data acquisition from external providers 2. Data validation and decoding 3. Data conversion into WXXM 4. Storage in a server environment that enables OGC web services; the OGC Web Services used are: a. WFS; Web Feature Service b. WMS; Web Map Service c. WCS; Web Coverage Service From a technology platform perspective, open source GeoServer and MySQL are used to host the identified processing steps. Figure 2-4 illustrates the interdependencies. Figure 2-4 Overview Technology Platforms 2.4 Data Sources The data sources selected for the demonstrator, to ensure that the intended objectives of the demonstrator are achieved, are numerous but managed in an efficient way. With connections set up between four selected data hubs and the Demonstrator environment, potential access Page 12 Error! Reference source not found. Edition: Error! Reference source not found.

15 to a variety of sources made available between and amongst the international meteorological service provider community is available. For the purpose of demonstrator we acquired access to the following data-hubs (providers): 1. SADIS The SAtellite DIstribution System of ICAO operated by the UK Met Office on behalf of the UK CAA as the ICAO SADIS Provider State. The SADIS provides all the mandatory internationally distributed data required by ICAO Annex 3. For the purpose of the demonstrator we used the back-up service (ftp-service) instead of the routine satellite distribution. 2. DWD The ftp-service of the German Weather Service (DWD) is used for acquiring weather radar information representative of the MUAC area of responsibility. The data is a socalled composite of weather radar data provided by Dutch, Belgian and relevant German and French weather radars. The composite is produced by DWD filtered for relevance above FL250 and made available in the Asterix (cat9) format. 3. KNMI The Royal Netherland Meteorological Institute (KNMI) ftp-service connections opensup several other sources of meteorological information. In the demonstrator architecture, KNMI provides access to numerical weather prediction (nwp) information produced by the European Centre for Medium Range Weather Forecasting (ECMWF), High Resolution Limited Area Model (HiRLAM) nwp capabilities, European composite weather radar information, Dutch weather radar information and local airport (Schiphol) observational data. 4. MADIS The Meteorological Assimilation Data Ingest System (MADIS) is dedicated toward making value-added data available from the US National Oceanic and Atmospheric Administration's (NOAA) Earth System Research Laboratory (ESRL) Global Systems Division (GSD). With the goal to improve weather forecasting, by providing support for data assimilation, numerical weather prediction, and other hydro meteorological applications but to also prototype new ways of distributing meteorological information. 2.5 Data Types, Formats and Conversion The data obtained via the various sources is made available in a variety of formats, known and unknown for ATM, but with one common feature they require expert systems or expert knowledge to provide, exchange or to use. Within the scope of the demonstrator, a series of products is selected that are representative for a product group and convert in a WXXM-compliant format. The following formats are converted: 1. TAC Traditional Alphanumerical Code (TAC) is currently used for the majority of ICAO Annex 3 type of messages. This includes aerodrome observations, aerodrome forecasts, SIGMET, Volcanic Ash Advisories, etc. 2. BUFR The Binary Universal Form for the representation of meteorological data is a World Meteorological Organisation (WMO) developed and owned code primarily used for the exchange of meteorological information between meteorological services. Some of the products required by ICAO Annex 3 are in the BUFR code format. 3. GRIB GRIdded Binary (GRIB) is a World Meteorological Organisation (WMO) developed and owned code format used for the exchange of gridded meteorological information. It is a well established format and also used outside the meteorological community. Edition: Error! Reference source not found.error! Reference source not found. Page 13

16 Products describing forecasted upper wind and temperatures as required by ICAO Annex 3 are in the GRIB code format. 4. HDF5 Hierarchical Data Format version 5 (HDF5) is the name of a set of file formats and libraries designed to store and organize large amounts of numerical data, fostered and supported by the non-profit HDF Group. HDF5 is mainly used in the supercomputing domain and an efficient alternative to some of the WMO formats for internal meteorological service provider data exchange or bilateral exchange between providers. 5. NetCDF Network Common Data Form (NetCDF)) is a set of software libraries and machineindependent data formats that support the creation, access, and sharing of arrayoriented scientific data. Similar like HDF5, NetCDF is used as an alternative to WMO formats. Note: NetCDF is a data format that looks very promising for the exchange of large sets of gridded meteorological data and the ability to be intelligently filtered/queried for the relevant snapshot in time and place from an ATM Business Trajectory perspective. This filtering/querying could be executed with the demonstrated capabilities of OGC Web Services. 6. Asterix All Purpose STructured Eurocontrol surveillance Information exchange (ASTERIX) is an ATM Surveillance Data Binary Messaging Format which allows transmission of harmonised information between any expert surveillance and expert automation system. For the demonstrator, the specific category of Asterix used by the Maastrich Upper Area Control centre is used (category 9) Initial Conversion Capability For the demonstrator, the following sample data and formats are converted: File type Data type Contained data Additional Converted? JETS Altitude Yes Speed wind Yes Date Localisation BUFR (SADIS) CAT Turbulence degree Date Altitude Min & max Date M_CLOUD Altitude Turbulence degree Air frame icing Page 14 Error! Reference source not found. Edition: Error! Reference source not found.

17 File type Data type Contained data Additional Converted? Cloud type Cloud distribution for aviation Embedded CB M_CAT M_FRONT M_JET Tropical cyclone Other parameters Airport localisation Date Time METAR /TAF(SADIS) METAR File Wind Visibility Precipitations Cloud Speed and direction Distance and orientation Temperatures Min & max Pression RVR Edition: Error! Reference source not found.error! Reference source not found. Page 15

18 File type Data type Contained data Additional Converted? TAF file METAR Forecast Wind share Other Tendencies Wind Direction and speed Temperature GRIB (SADIS) GRIB file Date Time Localisation Ice mixing ratio Experimental data Geo tiff HDF5 (KNMI) HDF5 file Radar Localisation NetCDF (MADIS) NetCDF file Pression Wind Temperature Direction and speed Minimum Date Localisation ASTERIX (KNMI) Asterix cat 9 file Precipitation Date Area and intensity VA_Advisory (SADIS) VA_Advisory file Localisation Source Date Name, summit, code Page 16 Error! Reference source not found. Edition: Error! Reference source not found.

19 File type Data type Contained data Additional Converted? Time Forecasts +6H, +12H, +18H Volcano active Aviation color code Edition: Error! Reference source not found.error! Reference source not found. Page 17

20 CHAPTER 3 The Demonstration 3.1 Findings An initial demonstration of the MET Data Fusion Demonstrator showed the concept, technology choices and underpinning architecture is well founded. The demonstrator environment is capable of ingesting a specified set of data, from various sources and in various data formats, to convert this data into a WXXM compliant format, to store the data and to make the data available by means of an appropriate OGC Web Service. The demonstrator makes available meteorological information as an OGC Web Feature, OGC Web Map or OGC Web Coverage Service, as appropriate, by simply identifying the data type to be converted. Figure 3-1 is a screenshot of the web interface in use to manage the demonstrator. This user interface also provides a rudimentary OGC Web Services client to view the WXXM compliant data. Figure 3-1 Demonstrator User Interface (screenshot) Page 18 Error! Reference source not found. Edition: Error! Reference source not found.

21 Figure 3-2 provides a screenshot of the Eurocontrol SkyView OGC compliant viewer with besides the visualisation of typical ATM related information such as airport maps, closed airspace also weather radar information. The weather radar information is processed by the demonstrator environment and picked up by the SkyView application as a Web Coverage Service. Figure 3-2 SkyView application with Weather Radar Information Demonstrator Implementation When converting large data sets the computer that hosts the demonstrator environment experiences memory allocation issues. The current set up hosts the geo-server environment with the attached converting mechanism, the web services capability and the user interface plus the MySQL database server. To load balance these activities is not trivial for a simple PC. The issue will be easily overcome when the demonstrator environment will be hosted, as foreseen, on the Eurocontrol test-server environment. This is a pending technical implementation issue resolved before the end of July 2009 based on the requirement to have the demonstrator environment available for potential information sharing and data fusion experiments till at least the end of Follow-Up Activities The demonstrator environment is seen by Central Flow Management Unit (CFMU) as extremely valuable for potential improvements to the Network Operations Plan (NOP) Portal. As such, the demonstrator is planned to be used by the CFMU to investigate its operational capability with respect to providing meteorological information services for the Network Operations Plan (NOP) Portal. Edition: Error! Reference source not found.error! Reference source not found. Page 19

22 3.3 Recommendations Data modelling: WXCM and WXXM modifications The initial demonstration revealed the need for improving the version of the used models (WXCM/WXXM/WXXS). The majority of changes are in improving the GML compatibility of WXCM/WXXM. A detailed overview of these modifications is listed in Annex 3. The proposed changes could be used in relation to a serious of activities linked with meteorological information data modelling in WP evolution of Demonstrator The MET Data Fusion Demonstrator project is mainly focused on the exchange of meteorological data by means of the WXXM and, as a potential way forward, to expose the weather information via OGC Web Services. In a SOA context the latter could be seen as rudimentary (meteorological) Information Services. See figure 3-3 for a high level overview of this separation of concern, the provision, exchange and use of the information. Figure 3-3 Knowing the current limitations of utilising available meteorological information by the ATM community, a next step could be to extend the life cycle of the demonstrator beyond what is agreed today (end 2009) and to use the capability of the demonstrator in example Business Services and Applications. In other words, the Meteorological Information Services made available by the demonstrator environment could be used by Applications and Business Services to be developed, tested or proofed, based on the requirements of the Operational Work Packages. An example in the context of Network Management could be a decision support system that suggest to the Network Manager the airspace available for the coming 24 hours based on airspace/route structures, foreseen closed airspace/routes and the forecasted weather, mainly convective weather. In the sketched context, information on airspace, routes and weather could be made available as an Information Services and the decision support system is the application that uses the Information Services, fuses the data, adds intelligence and makes available the required decision support. Page 20 Error! Reference source not found. Edition: Error! Reference source not found.

23 CHAPTER 4 Conclusions The MET Data Fusion Demonstrator, the instantiation of the WXXM SESAR WP8 Early Project clearly demonstrated that: The WXCM, WXXM and WXXS version are capable or exchanging meteorological information by an open and transparent means and applying open Industry Standards and Best Practices, some improvements to the model are proposed; The so-called separation of concerns, the separation of the provision, the exchange and the use of information is possible for meteorological information; Back-end system plumbing can be replaced by outward facing universal access the met component of the Intranet of ATM; A clear separation between service, interface and format is feasible for meteorological information whilst maintaining backward compatibility with existing formats for legacy investments; The user can be empowered to use multiple sources, multiple data domains to fuse the data for its business need and making the ATM System more predictable; It can open up potential quick wins when it comes to supporting CFMU Network Operations. Edition: Error! Reference source not found.error! Reference source not found. Page 21

24 ANNEX 1 Service Oriented Approach Since the ATM business is a complex business today, it is not completely understood yet how concepts will evolve over the years to come and to facilitate seamless transitions from the old to the new, it is highly beneficial to develop the Intranet of ATM with interoperability, flexibility and expandability high on the list of key requirements. To apply a Service Oriented Approach (SOA) in creating a state seamless, secured and filtered information sharing. SOA is an architectural style that encourages the creation of loosely coupled (business) services. Loosely coupled services that are interoperable and technology-agnostic enable business flexibility. An SOA solution consists of a composite set of business services that realize an end-to-end business process. Each service provides an interface-based service description to support flexible and dynamically re-configurable processes. There are many reasons to follow SOA design principles and options. The usual main goal is to build software that provides components that are usable by a variety of other components in a distributed environment (re-usable software components). Other goals include optimizing functionality, costs and non-functional requirements like scalability, performance, extensibility and security. What distinguishes service-orientation is the manner in which it carries out the separation of concerns and how it shapes the individual units of solution logic. Applying service-orientation to a meaningful extent, results in solution logic that can be safely classified as "serviceoriented", and units that qualify as "services." To understand exactly what that means requires an appreciation of the strategic goals of service-oriented computing combined with knowledge of the following service-orientation design principles: Standardized Service Contract: Services adhere to a communication agreement, as defined collectively by one or more service description documents Service Loose Coupling : Services maintain a relationship that minimizes dependencies and only requires that they maintain an awareness of each other Service Abstraction: Beyond what is described in the service contract, services hide logic from the outside world Service Reusability: Logic is divided into services with the intention of promoting reuse Service Autonomy : Services have control over the logic they encapsulate Page 22 Error! Reference source not found. Edition: Error! Reference source not found.

25 Service Statelessness: Services minimize resource consumption by deferring the management of state information when necessary Service Discoverability: Services are designed to be outwardly descriptive so that they can be found and assessed via available discovery mechanisms Service composability: Collections of services can be coordinated and assembled to form composite services A separation of concern in the real world, introduced by applying SOA, is the separation between the provision of the information and the use of the information. In today s ATM world, this distinction is not always clear and largely contributed to the fact that we have the so-called data stove pipes and no real sharing of information that enables true collaborative ATM decision making. Edition: Error! Reference source not found.error! Reference source not found. Page 23

26 ANNEX 2 OGC The Open Geospatial Consortium (OGC) is an international voluntary consensus standards organization. OGC members collaborate in an open consensus process encouraging development and implementation of standards for geospatial content and services, GIS data processing and data sharing. The mission of the OGC is to serve as a global forum for the collaboration of developers and users of spatial data products and services, and to advance the development of international standards for geospatial interoperability. Jointly with ISO TC211, OGC has developed an international standard for geospatial service architecture (ISO 19119) that provides a framework for developers to create software that enables users to access and process geographic data from a variety of sources across a generic computing interface within an open information technology environment For geographic information, ISO/TC211 standards specify methods, tools and services for data management (including definition and description), acquiring, processing, analyzing, accessing, presenting and transferring such data in digital / electronic form between different users, systems and locations. Where possible, the work shall link to appropriate standards for information technology and data, and provide a framework for the development of sector-specific applications using geographic data. The OGC specifications are divided into Abstract Specifications and Implementation Specifications. The Abstract Specifications provide the conceptual foundation for most OGC specification development activities. Open interfaces and protocols are built and referenced against the Abstract Specification, thus enabling interoperability between different brands and different kinds of spatial processing systems. The Abstract Specification provides a reference model for the development of OpenGIS Implementation Specifications. OGC Implementation Specifications target a technical audience and detail the structure of the interfaces between the distributed software components. The implementation of these specifications is determined to be at the proper level of detail if plug-and-play interoperability occurs between two software components that were engineered without knowledge of each other. The interfaces defined in the OGC s Page 24 Error! Reference source not found. Edition: Error! Reference source not found.

27 Implementation Specifications encourage loosely-coupled component architecture that is bound dynamically based on discovery and availability of services. Edition: Error! Reference source not found.error! Reference source not found. Page 25

28 ANNEX 3 WXCM/WXXM modifications Features modifications Observation Some GIS viewers display only features; this is related to the fact that features are realworld objectsto display observations from a GML file into a viewer as GAIA, this observation has to be features. This feature is just an extension of the GML AbstractFeatureType. Observation geometry To manage the observation target structure, all targets have to be features or geometries, but not both. To resolve this, a feature that represents geometries has been created. Observation Modifications Modification of the _Observation The _Observation type extends now the Observation feature. (See 0) Turbulence For the storage of turbulence information, a new kind of observation has been created. This observation is structured as followed: <element name="turbulence" type="wxxm:turbulencetype" substitutiongroup="wxxm:_observation"/> <complextype name="turbulencetype"> <annotation> <documentation>turbulence.</documentation> </annotation> <complexcontent> Page 26 Error! Reference source not found. Edition: Error! Reference source not found.

29 <extension base="wxxm:_observationtype"> <sequence> <element name="turbulencedegree" type="wxxm:degreeofturbulence" minoccurs="0"> <annotation> <documentation> Extended Degree of turbulence. </documentation> </annotation> </element> </sequence> </extension> </complexcontent> </complextype> <complextype name="turbulencepropertytype"> <sequence minoccurs="0"> <element ref="wxxm:turbulence"/> </sequence> <attributegroup ref="gml:associationattributegroup"/> </complextype> Modification of the surface wind observation A new element has been added to the SurfaceWind observation for the conversion of BUFR files. This element is the FlightLevelSignifiance and is represented by an enumeration defined in the DataTypes file. <element name="flightlevelsignificance" type="wxxm:flightlevelsignifiance" minoccurs="0"> <annotation> <documentation>flight Level Signifiance. </documentation> </annotation> </element> Modification of the cloud observation Cloud areas described in BUFR file contains information about the airframe icing and the degree of turbulence. To include this information in the WXXM file, the WXXM structure has been modified. The two following elements have been added to the CloudType : <element name="degreeofturbulence" type="wxxm:degreeofturbulence" minoccurs="0"> <annotation> <documentation>extend degree of turbulence. </documentation> </annotation> </element> <element name="icing" type="wxxm:airframeicing" minoccurs="0"> <annotation> <documentation>airframe icing. </documentation> </annotation> </element> These two elements are enumerations defined in the DataTypes file. Enumeration values come from the document Code-FlagTables pdf at page 52 and 85. Surface wind forecast GRIB files contain information about wind forecast. However, the actual WXXM standard doesn t define this kind of forecast. A forecast type to store wind information has been create to resolve this. <complexcontent> <extension base="wxxm:_forecasttype"> <sequence> Edition: Error! Reference source not found.error! Reference source not found. Page 27

30 <element name="hassurfacewind" type="wxxm:surfacewindpropertytype"/> </sequence> </extension> </complexcontent> Temperature forecast GRIB files contain information about temperature forecast. However, the actual WXXM standard doesn t define this kind of forecast. A forecast type to store temperature information has been created to resolve this. <complexcontent> <extension base="wxxm:_forecasttype"> <sequence> <element name="hastemperature" type="wxxm:temperaturepropertytype"/> </sequence> </extension> </complexcontent> Icing The conversion of GRIB files from ICE_TURB_CB directories needs the creation of different observation. The first one is Icing. This observation can contain information about the airframe icing or the ice mixing ratio. <complexcontent> <extension base="wxxm:_forecasttype"> <sequence> <element name="icingrisk" type="wxxm:airframeicing" minoccurs="0"> <annotation> <documentation>icing Risk.</documentation> </annotation> </element> <element name="iceratio" type="double" minoccurs="0"> <annotation> <documentation>ratio between kg of ice per kg of dry air.</documentation> </annotation> </element> </sequence> </extension> </complexcontent> Rain The conversion of GRIB files from ICE_TURB_CB directories needs the creation of different observation. The second is Rain water. This observation can contain information about the Rain water mixing ratio. <complexcontent> Page 28 Error! Reference source not found. Edition: Error! Reference source not found.

31 <extension base="wxxm:_forecasttype"> <sequence> <element name="rainratio" type="double" minoccurs="0"> <annotation> <documentation>ratio between kg of Rain per kg of dry air.</documentation> </annotation> </element> </sequence> </extension> </complexcontent> Snow The conversion of GRIB files from ICE_TURB_CB directories needs the creation of different observation. The last one is Snow. This observation can contain information about the Snow mixing ratio. <sequence> <complexcontent> <extension base="wxxm:_forecasttype"> <element name="snowratio" type="double" minoccurs="0"> <annotation> <documentation>ratio between kg of Snow per kg of dry air.</documentation> </annotation> </element> </sequence> </extension> </complexcontent> Messages modifications MessageCollection To avoid the creation of multiple GML files during the conversion of Volcano Ash Advisory or TAF from METAR, an equivalent of the FeatureCollection has been created. Data types modifications Degree of turbulence This new enumeration is defined in the DataTypes file and its values come from the BUFR extended degree of turbulence. Modification of the data type cloudkind New values have been added the enumeration to include BUFR cloud kind information. Edition: Error! Reference source not found.error! Reference source not found. Page 29