OGC and FAA

Registry for System Wide Information Management (SWIM)

AIM Scenario

The Aeronautical Information Exchange Model (AIXM) was developed by the Federal Aviation Administration (FAA) and Eurocontrol as a global standard for the representation and exchange of aeronautical information. It was designed as a basis for digital aeronautical information exchange and for enabling the transition to a net-centric, global aeronautical management capability.

AIXM was developed using the ISO 19100 modeling framework and has two major components: a conceptual model presented in the form of an UML class model, and a data encoding specification which was developed using the OGC Geography Markup Language (GML). Both have been tailored to the specific requirements for the representation of aeronautical objects, especially the temporality feature that allows for time-dependent changes affecting AIXM features.

Diagram of the AIM Scenario

Diagram of the AIM Scenario

The Aviation Information Management (AIM) subtask is a new thread within the OGC Web Services testbed. It is intended to develop and demonstrate the use of AIXM in an OGC Web Services environment. The AIM subtask is focused on evaluating and advancing various AIXM features in a realistic trans-Atlantic aviation scenario setting by devising and prototyping a Web Services Architecture for providing valuable aeronautical information directly to flight decks, Electronic Flight Bags (EFB), and hand-held devices (such as PDAs and Blackberries) while the airplane is at the gate or en-route to its destination (for the purposes of OWS-6, the aeronautical information in the latter case does not depend on the knowledge of the airplane’s location).

The key objective of the AIM thread in OWS-6 was to develop next generation concepts for air traffic control, in particular the ability to automatically and reliably distribute aeronautical and weather information, on a request or on an “as changed” basis, to pilots and to avionics systems.

AIM Architecture

AIM Architecture

The main focus of the project was to implement a message brokering system based on a Publication/Subscription infrastructure to mediate and transform xNOTAM messages based on the AIXM5 GML application schema between publishers and subscribers and to integrate other data sources based on different XML schemas such as WXXM.

Within the AIM thread, Galdos was responsible for the following tasks:

  1. Author of the AIM event-driven notification architecture document (Engineering Report) that addressed the change alert notification (xNOTAM) use cases.
  2. Recommendations of adaptations and extensions to the AIM schemas and data (for both aviation and weather), OGC Web Service standards and AIM use case scenarios.

The intention of the event-driven notification architecture document is to standardize: event descriptions, notification logic and advertisement/publication/subscription to service offerings, among other things.

Galdos provided architectural and technology recommendations and the implementation advice for open standards such as WS-Notification, WS-Security, and the WS-ReliableMessaging stack of protocols from OASIS/W3C.

Aviation Registry

Aviation resources such as AIXM features, portrayal rules, schemas, and metadata for datasets and services, were harvested in the OWS-9 project and published into the Galdos INdicio web registry service (OGC CSW-ebRIM) to enable optimal discovery and retrieval of these resources. Over one million registry objects representing the aviation resources and association between them were loaded into the aviation registry. The associations/relationships between the aviation resources were captured in conformance with the ISO TC211 19101-2001 Domain Reference Model applied to the aviation domain as illustrated in the following annotated diagram. The white boxes that annotate each of the shaded resource type boxes represent sample instances of resources deployed and managed in the registry.

Aim Registry Information Model

Aim Registry Information Model

The OGC Cataloguing ISO Metadata (CIM) registry model was used to represent and publish the aviation metadata resources as registry objects for the discovery and management of datasets and services. The CIM registry model (currently a draft specification being developed by the OGC CIM SWG) provides a standardized way to represent ISO 19115 and 19119 metadata as registry objects. The registry object instances were used to represent the resource types (service, dataset, metadata, application schema, feature instance, and geometry) and the association types (operates on, describes, defines the content of, contained feature, contained object, and spatial representation).

The following registry client screen shot shows the brief summary of a runway’s time slice metadata. The view is rendered in the client by styling a CSW-ebrim Web Registry Service (WRS) XML response to graphical form. In particular, the properties shown on the landing screen, include the contents of the ‘summary’ XML view (‘brief’, ‘summary’ and ‘full’ views can be requested from CSW-ebRIM), such as the name, description, type, life-cycle status, issue date, parent runway feature identifier info, and any other ‘slot’ properties of the object. Additional information can be seen in the client by clicking on the other tabs such as ‘Aliases’, ‘Tags’, ‘Associations’, ‘Repository Item’, and ‘XML’.

Brief Summary of Runway Time Slice

Brief Summary of Runway Time Slice

The following OWS services were harvested for service and dataset metadata:

List of Service Resources Harvested

List of Service Resources Harvested

In particular, the time-stamped resource inventory of feature and metadata instances offered by OGC Web Feature Service implementations (by Consort GmbH and Snowflake Software Ltd.) were captured to supplement the feature type service metadata found in OGC WFS capabilities documents. A screen shot showing the entire resource inventory of the Snowflake WFS as a dataset collection is shown in the registry client as follows:

AIXM Data Inventory Dataset

AIXM Data Inventory Dataset

The WFS dataset collection is organized into a hierarchy using the ISO 19115/19139 Dataset Metadata model. The Snowflake WFS dataset was divided into a collection of feature type datasets. For example the Airport Supplies Service feature type dataset is shown in the following registry client screenshot.

Airport Supplies Service Feature Type Dataset

Airport Supplies Service Feature Type Dataset

The WFS dataset collection metadata captures all of the fields specified by the requirements and guidance for the Aviation ISO 19115 metadata profile (OGC 11-171 and OGC 11-172). In addition, the registry captures data instance counts, metadata instance counts and raw XML document size, as summarized in the following table.

List showing Snowflake AIXM Data Inventory

List showing Snowflake AIXM Data Inventory