Singapore Workshop – Technical Focus - 16 June 2008 Temporality and Encodings Concepts and Examples Presented by Brett Brunk Aeronautical Information Management (AIM) group Federal Aviation Administration – United States

Singapore Workshop – Technical Focus - 16 June 2008 Topics  Temporality ●Why is it necessary ●AIXM 5 temporality concepts ●A NAVAID example  Example AIXM 5 Encodings ●Components of an AIXM 5 exchange file ●New Airspace ●Temporary change to airspace usage

Singapore Workshop – Technical Focus - 16 June 2008 Why do we need temporality?  Time is essential for aeronautical information  For operational reasons, distinction between: ●Permanent changes ●Temporary status  Two levels: ●Life of the feature ●Changes in properties

Singapore Workshop – Technical Focus - 16 June 2008 Temporality Model  Definition ●A model that incorporates the concept of time  Key assertions ●All features are temporal with start of life and end of life ●Example, A new air traffic control sector ●All features change over time ●Example, A VOR is out of service for a day  AIXM Temporality Model ●Relates features to the time extent in which they are valid ●Provides various means to describe the time extent

Singapore Workshop – Technical Focus - 16 June 2008 Time varying properties

Singapore Workshop – Technical Focus - 16 June 2008 The basic Time Slice model

Singapore Workshop – Technical Focus - 16 June 2008 The basic Time Slice model

Singapore Workshop – Technical Focus - 16 June 2008 The basic Time Slice model

Singapore Workshop – Technical Focus - 16 June 2008 The basic Time Slice model UML

Singapore Workshop – Technical Focus - 16 June 2008 Temporary events (digital NOTAM)

Singapore Workshop – Technical Focus - 16 June 2008 Temporary events  Two kinds of Time Slices ●Baseline = describes the feature state (the set of all feature’s properties) as result of a permanent change; ●Temporary Delta = describes the transitory overlay of a feature state during a temporary event.

Singapore Workshop – Technical Focus - 16 June 2008 Current status of a feature SNAPSHOT = describes the state of a feature at a time instant, as result of combining the actual BASELINE Time Slice valid at that time instant with all TEMPDELTA Time Slices applicable at that time instant.

Singapore Workshop – Technical Focus - 16 June 2008 Permanent changes PERMDELTA = A kind of Time Slice that describes the difference in a feature state as result of a permanent change.

Singapore Workshop – Technical Focus - 16 June 2008 Time Slice Types

Singapore Workshop – Technical Focus - 16 June 2008 Summary - Time Slice types  BASELINE = A kind of Time Slice that describes the feature state (the set of all the feature’s properties) as result of a permanent change;  PERMDELTA = A kind of Time Slice that describes the difference in a feature state as result of a permanent change;  TEMPDELTA = A kind of Time Slice that describes the transitory changes of a feature state during a temporary event;  SNAPSHOT = A kind of Time Slice that describes the state of a feature at a time instant, as result of combining the actual BASELINE Time Slice valid at that time instant with all TEMPDELTA Time Slices applicable at that time instant.

Singapore Workshop – Technical Focus - 16 June 2008 An Example: Navaid frequency change Imagine that AML Navaid undergoes an upgrade that changes its frequency from 112 MHz to MHz… 1.Schedule permanent change to coincide with AIRAC update cycle 2.Shutdown AML before the upgrade 3.Perform the upgrade 4.Start AML in test mode to evaluate change

Singapore Workshop – Technical Focus - 16 June 2008 An Example: Navaid frequency change AML Navaid undergoes an upgrade that changes its frequency from MHz to MHz…

Singapore Workshop – Technical Focus - 16 June 2008 Topics  Temporality ●Why is it necessary ●AIXM 5 temporality concepts ●A NAVAID example  Example AIXM 5 Encodings ●Components of an AIXM 5 exchange file ●New Airspace ●Temporary change to airspace usage

Singapore Workshop – Technical Focus - 16 June 2008 AIXM is based on International Standards Aeronautical Information Exchange Model (AIXM) ISO Spatial ISO Temporal ISO Metadata ISO Geography Markup Language (GML) Universal Markup Language (UML) Extensible Markup Language (XML) Conceptual standards Exchange standards

Singapore Workshop – Technical Focus - 16 June 2008 Extensible Markup Language (XML)  XML – Extensible Markup Language ●Have you looked at what is underneath a web page? ●XML has a similar look to HTML  Computer readable ●Electronic exchange ●Vendor supported SDAT 5.7 Release New Features >> Create traffic collections based on a sector number. (Flights flown through specified sector(s)) … SDAT 5.7 Release New Features >> Create traffic collections based on a sector number. (Flights flown through specified sector(s)) … 20L RIGHT … 20L RIGHT … Web Page HTML XML Document

Singapore Workshop – Technical Focus - 16 June 2008 Key Concept: Geometry and GML  Geometry important property of aeronautical information ●Airspace polygons ●Airport Reference Points ●Navaid location

Singapore Workshop – Technical Focus - 16 June 2008 Key Concept: Geometry and GML  ISO Geography Markup Language (GML) ●Vendor independent standard ●Based on XML ●Good industry adoption

Singapore Workshop – Technical Focus - 16 June 2008 Creating a new airspace 0bf9537f-27f a75f e51 … An AIXM Airspace Feature Unique Identifier for the Airspace. Computer readable Container for the timeslices that make up the airspace End of the Airspace Feature Definition of the airspace

Singapore Workshop – Technical Focus - 16 June 2008 Creating a new airspace continued … T00:00:00 BASELINE T00:00:00 … other properties Baseline timeslice containing all feature properties Period of validity for timeslice Period of validity for the Airspace feature

Singapore Workshop – Technical Focus - 16 June 2008 Creating a new airspace continued … … TSA EBT15 LO-RENINGE UAV AREA MIL G … Airspace Feature properties Airspace shape and volume

Singapore Workshop – Technical Focus - 16 June 2008 Creating a new airspace continued … … 95 STD 4500 MSL … Upper and lower limits GML definition of horizontal boundary

Singapore Workshop – Technical Focus - 16 June 2008 Creating a new airspace continued … … …

Singapore Workshop – Technical Focus - 16 June 2008 Demonstration  Viewing AIXM features in a commercial product ●LuciadMap’s prototype AIXM Viewer