Mr vedadian by LBY2ks


									Data link in

              Data link
 Aeronautical telecommunication network
  (ATN) data link:
 Air-ground data link

 Error decreasing

 High reliability

 Data transmission in high speed
                  Data link
   High accuracy in transmission
   Print of information
   Decreasing of traffic in communication
   Transmission of data in text or even in
   To decrease of controllers workload
   To decrease of crew workload
               Data link

 To understand the information easily and
 To display the information in any media
  like windows.
             Data link

Data link is the basic component of
communication between air traffic
controller (ATC) and aircraft.
      Data link in CNS/ATM
   Data link channels:

 ATC Mode-S


                 ATC Mode-S

   data link capability:

    A/C to ground stations (downlink)

    ground stations to A/C (uplink)

    air to air
                ATC Mode-S
   ATC Mode-S Transponders support:
    all surveillance functions (UF 0,UF 4,UF 5,
    DF 0,DF 4,DF 5,DF 11).
   - bidirectional air to air data link (UF 16,
   - ground to air data uplink (comm. A)
   - air to ground data downlink (comm. B)
   - uplink ELM & downlink ELM.
          ATC Mode-S / ELS
   SI codes are the way to identify
    interrogating stations in order that the A/C
    can selectively answer to them. So, only
    the interrogating station receives the

   Also, the flight ID (flight number) is
    downlinked to ground.
ATC Mode-S / ELS
          ATC Mode-S / EHS
   ATC Mode-S Enhanced Surveillance (EHS)
    was mandatory with effective date of
    march 2007.
   Enhanced Surveillance is the first stage in
    making use of air derived data in the form
    of Downlink Air Parameters (DAPs), either
    directly to controller or to ATC systems.
         ATC Mode-S / EHS
- magnetic heading     - selected altitude

- true track angle     - track angle rate

- indicated airspeed   - mach number

- true airspeed        - ground speed

- roll angle           - vertical rate
          ATC Mode-S / EHS
   information transmitted to ground causes
    the controller to supervise accurately on
    the aircraft.
   The controllers receive much more
    information and the quality is increased.
   In high density traffic like Europe, all of
    the parameters will be easily available to
    the controllers and so, the pilot has not to
    report them.
          ATC Mode-S / EHS
   Therefore, the pilot might not use the
    VHF voice which causes decreasing of VHF
    bands traffic.
   The DAPs from different systems on the
    A/C, are received by ATC Mode-S
    Transponder. The Transponder downlink
    them as the replies of the interrogations.
   The project causes decreasing of the
    errors in controllers supervision.
            ATC Mode-S
   Extended Length Memory (ELM):

16 words 80 bits in each interrogation

16 words 80 bits in each reply
       ATC Mode-S data link

   Long messages are transmitted using
    Extended Length Message (ELM)
   ELM is capable of transmitting up to
    sixteen 80 bits message segments, air to
    ground or ground to air. No surveillance
    data is considered in ELM.
   ELM can be acknowledged by a single
    reply or interrogation.
       ATC Mode-S data link
   ELMs uplinked need not be replied to
    individually, but can be acknowledged in a
    reply containing a summary of the
    received interrogations.
   Downlinked ELMs are transmitted only
    after authorization by the interrogator.
    The segments are transmitted in comm D
              VHF Data Link
   In future, voice communication will be
    used for critical messages:
   To avoid traffic
   Landing clearance at airports with heavy

   It will serve as back up for data link.
   The VHF Data Link (VDL) operation
    requires a VHF digital radio (VDR).
             VHF Data Link
   VDL is essential for ATN implementation.

   The VDL formats specify a protocol for
    delivering data packets between airborne
    equipment and ground systems.

   The protocol is different to that used in the
    aircraft communication addressing and
    reporting system (ACARS).
             VHF Data Link

   The difference is that the VDL provides a
    capacity 13 times greater than the
    equivalent of 25 KHz VHF channel.
               VDL Mode-1

   This mode has been especially designed to
    use ACARS.

   VDL mode-1 is a low speed bit oriented
    data transfer system.

   It uses carrier sense multiple access
    (CSMA) methodology.
             VDL Mode- 1
   VHF analogue radios: for data exchange
    since the late 70s.
   ACARS system has been developed and
    has grown considerably.
   VDL Mode-1 has been especially designed
    to use ACARS modulation equipment and
   ACARS and VDL mode-1 is a low speed bit
    oriented data transfer system.
               VDL Mode-2
   VDL- Mode 2 uses same technology, but
    is not capable of handling voice

   Average data transmission is 31.5 kbps. It
    employs a globally dedicated common
    signaling channel of 136.975 MHz.
            VDL Mode-2

 VDL Mode-2 is the minimum requirement
  in CNS/ATM.
 Commercial services are available at the
  time being.
 VDL Mode-2 transmits coded data. (ie.

  in CPDLC)
 It is not necessary to send letters and
  numbers like ACARS.
            VDL Mode-2
 The message “Climb to and maintain FL350”
  requires about 10 bits.
 This is the technology to speed transmission
  of information.
 Bit rate: 31.5 kbps

 Modulation: D8PSK

 A/C address is the same as ATC Mode-S

  Address (24 bits)
              VDL Mode-2
   A/C and ground stations exchanges the
    information in frames.

   Each four frames of information require
    one acknowledgement.
   Data link communication according to the
    protocol specified in ICAO VDL Mode-2
    and AMSS Data 3 standards.
              VDL Mode-2
   VHF Digital Radios capable for ACARS
    don’t meet the requirements of the
    protocol ICAO VDL Mode-2.

   VDL Mode-2 is not capable of handling
    voice communication.
              VDL Mode-2
   Communication Management Unit (CMU)
    or Air Traffic Service Unit (ATSU) manage
    transmission of digital information of
    the following systems:
    CPDLC (using VDL Mode-2)
    ADS-B (in future VDL Mode-4 probabely)
    ATC Mode-S
               VDL Mode-2

   Communication Management Unit (CMU)
     or Air Traffic Service Unit (ATSU) should
    be capable to handle the ISO-8208 (X.25
    protocol specified in ICAO VDL standard.
              VDL Mode-3

   VDL Mode-3 is an integrated digital data
    and communication system.
   VDL Mode-3 uses four radio channels on a
    carrier (with a 25 KHz spacing).
   VDL Mode-3 uses a data link technology
    called TDMA.
   It is presently is not available for
    operational use.
           HF data link (HFDL)
   HF data link (HFDL) is another communication
    channel to transmit data from ground station to
    A/C and via versa.
   HFDL uses HF frequencies.

   HFDL is the only standby system for
    aeronautical mobile satellite system (AMSS) in
    oceanic / remote areas.
         HF data link (HFDL)

   The propagation anomalies rarely affect
    the entire HF frequency band.

   HFDL communicates with a number of
    adequate frequencies available in the HF
    band, to find the best frequency for
    transmission of data packages anywhere
    and at any time.
         HF data link (HFDL)
   Upon a suitable frequency is found, a
    log-on message is sent to ground station.

    Upon receiving of log-on confirmation, the
    information is sent (downlink) to ground
    A new frequency search is initiated after
    ground station has not acknowledged.
        HF data link (HFDL)

   Bit rate: 300 to 1800 bps.
   range: 6000 km
   coverage: oceanic and polar region
         HF data link (HFDL)

   In this mode aircraft can contact three or
    more HFDL ground stations constantly and
    its hub can become ATN routers.
        HF data link (HFDL)
   The A/C equipped with:

   HFDL Control Panel
   HF Data Unit plus HF Voice Radio or
    HF Data Radio
        HF data link (HFDL)

   HFDL important role:

   Not SATCOM equipped A/C , long range
   Data link for polar regions
  Aeronautical Mobile
Satellite Services (AMSS)
   VHF Data link /ATC Mode-S Data link:
     - line-of sight restriction.
     - certain range
     - require support of ground stations,
       electric power, maintenance, etc.

    not appropriate for oceanic / long range
      Aeronautical Mobile
    Satellite Services (AMSS)

   HFDL it is unsafe, medium quality, technical
    support, low speed, etc.

   Satellite communication:
    - high-quality voice and data communication
  Aeronautical Mobile
Satellite Services (AMSS)
    AMSS provides:
    - digital voice and data services

    Data link:
    - communication services
    - broadcast (WAAS, EGNOS)
   Geostationary satellites

   Coverage: long range, oceanic, non-polar

   Bit rate: 10.5 kbps in max.

   Data link capability

   ICAO AMSS Standard data 3
   L-band:
    1545 to 1555 MHz
    1646.5 to 1656.5 MHz.

   Services:

    - CPDLC

    - ADS-B

    - etc.
   Current SDUs provide services to ACARS
    will be replaced by SDUs which meet the
    requirements specified in AMSS Data 3
    Controller-Pilot Data Link
    Communication (CPDLC)
   The Air Traffic Control (ATC) system relies
    heavily on voice communications between
    air traffic controllers and pilots.

   It is to relay control instructions and other
    information critical to safe and expeditious
    Controller-Pilot Data Link
    Communication (CPDLC)
   These communications are required to
    support coordination of aircraft movement
    in all phases of flight, to ensure:
   Aircraft separation
   Transmit advisories and clearances
   To provide aviation weather services.
    Controller-Pilot Data Link
    Communication (CPDLC)
   As air travel continues to increase,
    controller-pilot communication has
    increased to the saturation point during
    peak traffic periods at many locations.
   The workload of controllers increased
    more and more.
   This wastes more time on the ATC voice
    channel as repeated attempts to
    communicate are made.
    Controller-Pilot Data Link
    Communication (CPDLC)
   Saturation: no additional aircraft can be
    handled within the controller's assigned
    airspace .
    Controller-Pilot Data Link
    Communication (CPDLC)
   Air Ground Data Link (AGDL): a means of
    communications between pilots and
    controllers, using data link instead of voice.

   This type of communication between pilots
    and controllers is often referred to as
    Controller-Pilot Data Link Communications
    Controller-Pilot Data Link
    Communication (CPDLC)
  Air Ground Data Link helps to solve the of
   the voice channels, the important problem
   for Air Traffic Controllers.
 introducing an
 AGDL introduces an alternative means of
   communication between the aircrew and
   the controllers, data link.
 CPLDC is used to relay routine messages
   from aircrew to controllers and via versa.
Controller-Pilot Data Link
Communication (CPDLC)
   CPDLC Data link messages (uplinks):

    - Check microphone (AMC)
    - Change SSR code/- Squawk ident
    - Contact (ACM)
    - Direct flight to turn and heading
    - Altimeter settings for conforming of flight
      level instructions
  Controller-Pilot Data Link
  Communication (CPDLC)
- Initial contact altitude verification to ensure
  that pilot and controller's
- Understanding of a flight's altitude clearance
  agrees on check-in
- Voice frequency assignments for hand-offs or
  radio transmitter problems
- Crossing restrictions for arrival and departure
  transitions/to comply with airspace restrictions
  Controller-Pilot Data Link
  Communication (CPDLC)
- Menu text for weather alert or traffic flow
- Route clearances
      Controller-Pilot Data Link
      Communication (CPDLC)
   CPDLC allows the information, such as
    aircraft parameters, to be down linked to
    the ground stations automatically.
    Controller-Pilot Data Link
    Communication (CPDLC)
    Data link messages (downlinks):
    - Altitude
    - Speed
    - Heading
    - Turn
    - Climb/descent/maintain flight level (ACL)
    - Flight plan
    Controller-Pilot Data Link
    Communication (CPDLC)
   Aircrew answer ATC instructions by data link
    and request routings from ATC.
   All of these messages will be exchanged
    without the need for voice read-back.

   CPDLC communication: not intended to be as
    fast as voice. It is designed to pass routine
    messages, where time is not an critical
    Controller-Pilot Data Link
    Communication (CPDLC)
   The best analogy one could make for
    air/ground data link or CPDLC is that of a
    mobile phone.

   The use of CPDLC in high-density traffic
    airspace offers the potential to reduce
    voice channel traffic and to improve the
    Controller-Pilot Data Link
    Communication (CPDLC)
   Using CPDLC reduces the pilot's and the
    air traffic controller's communication
    workload and allows them to concentrate
    on other essential tasks.

   CPDLC transmits the information through
    VDL Mode-2 or geostationary satellites.
    Controller-Pilot Data Link
    Communication (CPDLC)
   CPDLC is windows-based for the controller.

   All of the actions are performed via the
    radar screen, using a mouse, the data link
    window and pre-defined menus.
    Controller-Pilot Data Link
    Communication (CPDLC)
   Colors are used to highlight the different
    states of a message.

   Uplink message awaiting a response from
    crew, is displayed in light green to the
    Controller-Pilot Data Link
    Communication (CPDLC)
   Downlink request from the aircrew will
    display in white.

   The colors show in the data link window.

To top