(Updates f

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UpdatingOnboard-Databases

• (Updates für Onboard-Datenbanken)

Author Christian Grothe
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Overview / Agenda
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Static Cockpit Data - Trends

• More onboard applications use electronically
  stored (static) data
• Data(bases) integrated in appliances
• Trend integrate all kinds of stored data in one
  database (server)
• Timeliness of data critical
• Problem keeping data up-to-date

? Update Solutions Needed! ?
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Onboard Applications - Examples

• Synthetic Vision Systems (SVS)
• enhancing situational awareness by displaying the
  aircraft in its environment terrain, obstacles,
  navaids,

• Taxi Positional Awareness
• birds eye view display moving map of airport
  with own aircraft for enhanced situational
  awareness to avoid runway incursions

• Flight Management System
• allows programming of flight plan to be used by
  auto pilot, supported by visual representation
• standard equipment in every aircraft!

• Chart Generation
• replace cockpit paper charts (procedures, airport
  map, ) used by pilots today with dynamically
  created charts

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Aviation Data - Classification

• 4 Classes of electronically stored, static
  Aviation Data used in onboard applications
• Navigation data
• Terrain data
• Obstacle data
• Airport Mapping data
• (Cultural data)
• Semi-static or dynamic Data
• Weather data
• Traffic data
• Performance data
• Will concentrate on static data

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Navigation Data

• Information about artificial (man-made, real or
  virtual) objects used for navigation
• Procedures approach, arrival, departure,
  missed-approach
• Navaids position, frequencies, types (VOR, NDB,
  DME, VORTAC, ...
• Airports/Heliports frequencies used, runways,
  ILS, MSA areas
• Airways, Airspaces special/ restricted usage,
• Storage format ARINC424
• old (70s), complex (specification gt350 pages)
• defines concepts, structures and dependencies of
  navigation data
• ASCII format
• optimized for fast retrieval in FMS

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Terrain Data

• Model of earth surface
• describes elevation (deviation from earth
  ellipsoid)
• usually measured at equidistant posts, distance
  between posts post-spacing
• typical post-spacing values 30, 3, 1 arcsec
  (DTED0,1,2)
• 2 different models DSM/DTM (Digital
  Surface/Terrain Model), with/without vegetation,
  canopy/bare earth model

• Storage format DEM (Digital Elevation Model)
• grid file binary/ascii elevation values in
  columns/rows
• header information with lat, long, post-spacing,
  cols, rows

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Obstacle Data

• Information about (significant) obstacles for
  aviation
• 3 Types point obstacle (antenna, building, tree,
  ), line obstacle (power line, cable, fence, ),
  polygon obstacles (usually not used)
• line obstacle represented as set of posts (line
  string)
• position(s), type, horizontal dimension
  (diameter)
• Storage format tables or gis
• table format simple, one row per point obstacle
  or line obstacle post, often as ascii (csv)
• gis as point/line/polygon shapes, attributes
  added to the shape

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Airport Mapping Data

• Map of an airport
• every (group of) airport element described
  separately buildings, runways, taxiways,
  markings
• attributes added to every element surface type,
  height, name,
• Storage format AMDB
• gis storage format ESRI shape (shp) files,
  geometrical shapes (point, line, polygon) with
  additional attributes (in DBase dbx files)

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Measurements Relevant for Updates (1)

• Volume
• How much data? Value in bytes per region
• Changeability
• How often does data in change? Value in percent
  per time and region
• Connectivity
• How much are data items interconnected/
  dependent? Unit? ? qualitative answer
• Relevance for safety
• How important is the data for operation
  reliability? Unit? ? qualitative answer
• Problem Lots of estimation and approximation

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Measurements Relevant for Updates (2)

• Volume (worldwide, binary format)
• Navigation 160 MB
• Terrain 500 MB (30 arcsec post-spacing)
• Obstacle 30 MB
• AMDB 500 MB
• Changeability (per month)
• Navigation 5
• Terrain 8.17e-8
• Obstacle 0.5
• AMDB 1
• Connectivity
• Navigation high
• Terrain none
• Obstacle none
• AMDB medium

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Acquisition ways for aeronautical data

• Data Providers
• like Jeppesen, Lido
• get data from different sources publicly
  available (land surveying office), bought or own
  surveilling)
• verify, process, integrate, tailor data for
  customers (airlines, aircraft manufacturer)
• responsible for quality!
• Aeronautical Information Services (AIS)
• processes defined by ICAO
• every member state publishes AIP and Amendments,
  Supplements thereto
• AIP contains information about national
  regulations, responsibilities (ATC centers),
  procedures, airways, etc.
• changes become effective on special dates (28
  day cycle)
• temporary or short term changes published in
  NOTAM (Notice to Airmen)

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Aeronautical Information Services (AIS)
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Board/Ground Data Exchange

• Data Medium manual transport and integration
• diskette, cd, dvd, memory cards,
• loaded into the board systems over data loader
• standard today!
• Gatelink WLAN at the terminal
• only some airports have gate link
• not standardized, isolated application
• Connexion by Boeing Broadband Internet over
  satellite
• proprietary solution, operational since 5/04
• only few aircraft equipped (some 30), 5 airlines
• Data Links / ATN

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Data Links (1)

• Only data connection to aircrafts approved and
  certified by ICAO
• Data Link Service Provider (DSPs) like SITA and
  ARINC offer ground routing of data
• ACARS first data link
• starting 70s, meant to be used for AOC messages
• automatic messages (through triggers) and
  manually entered messages possible
• protocol 2.4 kbit/s, character oriented, medium
  access stop-n-wait ? only short text messages
• widely used! channels congested
• Benefit of data connection to airplanes realized
  by industry lately (90s)!

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Data Links (2)

• VHF Digital Data Link (VDL)
• 3 flavors Mode 2, 3, 4
• different protocols, 19.2/31.5 kbit/s
• Mode 2 operational today, transition from ACARS
  in progress ACARS over AVLC (AOA)
• Mode 3 and 4 to come (M3 favored by US, M4
  favored by Europe)

• Mode S Secondary Surveillance Radar
• radar beam used to interrogate transponder and
  send data (4 Mbit/s)
• transponder sends surveillance data and user
  data (1 Mbit/s)
• main problem data can be exchanged only when in
  center of radar spot beam results in some 100
  bit/s
• not operational for industry use yet, tests for
  use by ATC in progress

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Data Links (3)

• Satcom
• Inmarsat (geostationary) 0.6 - 9.6 kbit/s
  (64kbit/s), does not cover polar regions
• Iridium (LEO) 2.4 kbit/s, equipment much cheaper
• data transfer expensive, therefore used only in
  oceanic regions

• HF Data Link (HFDL)
• offered only by ARINC, 2 to 30 MHz, long range
• low transfer rates 0.3 1.8 kbit/s
• competition for Satcom, used primarily on polar
  routes
• needs special antennas, not widely used

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Aeronautical Telecommunication Network (ATN)

• Main Problem of Data Links varying equipage
• Idea one network, integrating different data
  link subnetworks interoperably
• ATN initiative started in early 90s by ICAO,
  RTCA, ATA, IATA, AEEC
• Network based on X.25 concepts
• 4 main elements
• network mobility location transparency
• QoS specify costs, transfer rate, connection,
• data compression accounting for data links low
  bandwidth
• standardization of services for ATS applications
• Problem with implementation nobody wants to do
  the first step

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Routing and Mobility in the ATN

• Hierarchical Routing network is divided in
  Routing Domains (RDs), every RD has one backbone
  router (BR)
• Unique address of every participant consists of
  home domain and end system address
• IDRP Routing paths to end systems are propagated
  between BRs towards home domain only
• Simple routers only know path to next BR

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Routing and Mobility in the ATN
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Update Procedures

• Based on operational constraints, safety issues,
  certification problems and feasibility
  limitation, different design options are possible
• Full Update or Incremental Update?
• Full Update (better Replacement) very simple,
  impact on onboard server implementation
  read-only state as of today
• Incremental Update Much smaller update packages
  (for online submission), but have to care for
  lost updates, integrity checking,
• Data Delivery Options
• initiated by provider, when new data is
  available push
• initiated by operator, when up-to-date data is
  needed pull
• periodical, without trigger