Future work OWS-8 Aviation Architecture Engineering Report
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services deployed on it. Work on SOAP and WSDL for OGC Web Services has been performed in
previous OGC initiatives see OGC 08-009r1. This work should be reviewed and updatedextended to take into account IT standards such as WS-Addressing,
WSDL 2.0 and the WS-I BasicProfiles.
Temporality Model as standalone specification and better support for time varying data in OGCISO standards – The AIXM Temporality Model defines
encoding as well as business rules that enable applications to keep track of time varying data, in this case of AIXM features and their properties. Refactoring the
Temporality Model into a standalone specificationstandard would be beneficial for the following reasons: a enable re-use of the concepts defined by the
Temporality Model in other domains that deal with time varying data, b improved maintenancegovernance of the Temporality Model itself, c improved
interoperability and usability when handling and managing time varying data via web services. Section 10.1.6 explains this in more detail. The ideas and
suggestions presented in that section should be considered in the future. Improved usability and interoperability in model design and encoding as well as
management and access of time varying information are key benefits of the suggested refactoring. Section 10.1.6 also outlines how this could be achieved by
revisingextending a set of OGC and ISO standards.
Aviation Event Architecture
o
Dynamic spatial filtering – Future work on the dynamic spatial filter
should cover processing as well as architecture modeling and interface definition aspects. A combination of temporal filters and dynamic spatial
filters is imaginable. For instance, an SAA in a near upcoming part of the flight route may be activated but the start time of the activation is three
hours from now. Obviously, a pilot or dispatcher is not interested in such an Event as the airplane will have passed this airspace already three hours
before the activation takes place given that the route segment can be traversed in three hours. Missing such events because of application of
dynamic filtering must be regarded from a security aspect as well; however, this mechanism can help clients to receive and act only upon
those events that are of interest. Additionally, the design of the EML should be improved to reduce the current complexity. This accompanies a
general review of the EML model with respect to dynamic event patterns and parameters. In general, alternative approaches to using EML could be
investigated.
o Simplification of subscription methods – Specific requirements from a
client perspective should be included in the design of subscriptions. This includes the simplification of interfaces as a client should not deal with
such complex markup languages if only a rather small and specific subset of the given functionality is used. This concerns the way that filter
statements are created. Various options to improve the situation should be
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Inc. All Rights Reserved.
5
discussed such as domain specific filter functions and stored subscriptions in Event Services. Work topics could cover the development of interfaces
as well as general investigations on contents for such stored subscriptions.
o Provision of aircraft position updates – in the case that the receipt of
aircraft positions using ADS-B is considered as appropriate several architectural aspects need to be taken into consideration. From an Event
Service point of view receiving a vast amount of position updates from different aircrafts is problematic due to performance limitations. The event
architecture could benefit from some sort of broker service for position updates. An Event Service receiving a subscription for a specific flight
route with an assigned CallSign could then subscribe at such a broker service for position updates of the aircraft with this call sign. Thus, an
Event Service only receives those position updates which are relevant for the currently registered subscriptions. In general, it may also be reasonable
to hide such a broker architecture behind the façade of a possible authoritative Event Service which would provide a global interface for
subscribing to DNOTAMs.
o Conceptual work on enrichment of thin events within an Event
Service – during this testbed the developed enrichment design has been applied while processing events. What is currently missing is the
conceptual integration of this feature into the overall model of the Event Service. Future work on the enrichment of thin events should consider the
integration into the service metadata. A client using the Event Service would then be able to determine if it is capable of pulling additional
information from a WFS data store, thus being able to define appropriate subscription filters. This would also imply the definition if an Event
Service supports the retrieval of AIXM feature Extracts for a certain period of time see section 10.1.3 for further details on “Extract”.