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Updating Onboard-Databases. (Updates für Onboard-Datenbanken). Author: Christian Grothe. Overview / Agenda. Static Cockpit Data - Trends. More onboard applications use electronically stored (“static”) data Data(bases) integrated in appliances
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UpdatingOnboard-Databases (Updates für Onboard-Datenbanken) Author: Christian Grothe
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!←
Onboard Applications - Examples • Synthetic Vision Systems (SVS) • enhancing situational awareness by displaying the aircraft in its environment: terrain, obstacles, navaids, … • Taxi Positional Awareness • bird’s 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
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
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: >350 pages) • defines concepts, structures and dependencies of navigation data • ASCII format • optimized for fast retrieval in FMS
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
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
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)
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)
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
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)!
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
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
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
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