cpdlc atn vdlm2 tutorial

CPDLC/ATN/VDLm2 TutorialSafety in the Air 2009Montego Bay, Jamaica, January 28-29, 2009

Patrick Geurts

ATM Business Development Manager, Europe

Safety in the Air | January 28-29, 2009 | 2 SITA proprietary and confidential information. SITA 2008 All rights reserved.

Agenda

Introduction

CPDLC

ATN

VDLm2

Synthesis


Objectives of this Tutorial Data Links are used for year for tower and en-route

applications, based on the dating ACARS protocols

The European Union has mandated the use of CPDLC/ATN/VDLm2 in its upper airspace by 2013

This tutorial will address: The CPDLC application

The ATN protocols

The VDLm2 A/G data link technology


Agenda

Introduction

CPDLC

ATN

VDLm2

Synthesis


FANS story FANS 1 Committee

1980: Limitations of current system identified 1983: FANS 1 Committee established to develop CNS/ATM system for 21st

Century 1988: Satellite-based CNS/ATM concept complete

FANS 11 Committee Defines a global CNS/ATM Implementation Plan 1990: First FANS 11 Committee meeting 1991: Concept endorsed by ANC

Equipage 1993 : Boeing FANS applications in the Honeywell FMS installed on the B747-400

(FANS/1) 1995 : First B747-400 certified (Quantas) 2000 : Airbus develops the ATSU supporting FANS application for A340/A330

(FANS/A) 2005 : Boeing and Airbus develop the FANS 1/A+ enhancement package


FANS 1/A applications

AFN (ATS Facilities Notification) Allows aircraft to logon to ATC facility & the transfer of control

CPDLC (Controller Pilot Data Link Communications) Replaces for verbal ATC instructions and pilots read-backs Automates ATC processes

ADS (Automatic Dependent Surveillance) Gives accurate position reporting Allows additional data reporting (wind, temperature etc) Providers reporting in regions out of radar coverage Significantly increases traffic that can be handled in remote areas


The AFN application

AFN stands for Aircraft Facility Notification. AFN is the FANS equivalent service as the ICAO defined as

Context Management (CM). Referred to as Data link Initiation Capability (DLIC) Service in

Link2000+ terminology. AFN process is made of several steps.

The aircraft logs on to a Facility (CM logon request) The Facility Ground System checks if the aircraft is entitled to

logon, and responds either positively or negatively. When necessary, the Facility Ground System will request the

aircraft to logon to the next sector. The aircraft will notify when the next logon is completed.


FANS applications Context Management

CM Logon Request

CM Logon Response


FANS applications - CM forward

4 - CM Logon Complete

1 - CM Logon Forward

3 - CM Logon Response

2 - CM Logon Request


The CPDLC application

CPDLC stands for Controller Pilot Data Link Communication. Referred to as Air Traffic Clearance (ACL) Service in the

Link2000+ terminology CPDLC application consists for the controller and the pilot the

exchange ATC requests and instructions over datalink rather than the VHF or HF radio.

CPDLC enables the automation of routine communication (e.g transfer of control).

CPLDC programs on going in the NAT and SoPAC (FANS), as well as USA and Europe (ATN).

There are differences between the FANS and the ATN definition ofthe CDPLC application.


FANS applications - CPDLC

WILCO

CLIMB TO FL370


Example of CPDLC: Controller HMI


Example of CPDLC: Pilot HMI


Sending a CPDLC request: Airbus DCDU HMI


Wilco: Airbus DCDU HMI


Agenda

Introduction

CPDLC

ATN

VDLm2

Synthesis


ATN Original Architecture

BUT: ATN has never developed into a general purpose network Limited to support ATC Air/Ground data link applications, in particular

CPDLC over VDLm2, as mandated in Europe


Support for Mobile Communications

The ATN architecture: Supports mobile routing to aircraft Supports ground-ground fixed routing Covers air/ground mobile subnets

Subnetwork must be bit-oriented Data Compression for efficient use of limited bandwidth

In practice: VDL mode 2 used over high-density traffic regions VDL mode 2 is digital and offers 31.5 kbps compared to

2.4 kbps for Plain Old Analogue ACARS


Application

Presentation

Session

Transport

Network

Data Link

Physical

Managem

entApplication

Presentation

Session

Transport

Network

Data Link

Physical

Managem

ent

PhysicalCommunications Media

Network

Data Link

Physical

END SYSTEM

INTERMEDIATE SYSTEM

END SYSTEM

ATN Protocol Stack


ATN as an Internetwork

ES

ATM Application

ES

ATM Application

ES

ATM Application

ES

ATM Application

IS

IS IS

IS

IS

ISATN

Internet

ATN


ATN Encapsulation: example for AMHSLayer 7: APDU ROSEAPDU

RTSEAPDU

P1Header

P22IPM

Layer 6, 5: Fast Byte FB ROSEAPDURTSEAPDU

P1Header

P22IPM

Layer 4: TP4 TPDU TPDUHeader FBROSEAPDU

RTSEAPDU

P1Header

P22IPM

Layer 3a: CLNP NPDU NPDUHeaderTPDU

Header FBROSEAPDU

RTSEAPDU

P1Header

P22IPM

Layer 3B: Convergence NPDUHeader

TPDUHeader FB

ROSEAPDU

RTSEAPDU

P1Header

P22IPM

Layer 3a: X.25 PacketP(S)

P(R)

Mbit...

NPDUHeader

TPDUHeader FB

ROSEAPDU

RTSEAPDU

P1Header

P22IPM

Layer 2: LAPB FrameADR

CtrlFlag FlagFCS

NPDUHeader

TPDUHeader FB

ROSEAPDU

RTSEAPDU

P(S)

P(R)

Mbit...

P1Header

P22IPM


COTP/CLTP

CLNPData LinkPhysical

End System

FAST BYTE PRESENTATION

SESSION

APPLICATION ASEs

SUBNETWORK

End System

ATN End System support: Application ASEs

one per application FAST BYTE Session &

Presentation Layers CO & CL Transport Layer CL Network Layer


Intermediate System

IS can be: Air/Ground Ground/Ground Airborne

ISs support: CL Network Layer Mobile SNDCF IDRP ES IS Routing subnetwork mobile

subnetwork

IDRP ES-ISCLNP CLNP

SNDCF SNDCF-MOBILESNAcP SNAcP

Data Link Data Link

Physical Physical

Intermediate System (ATN

Router)


Support for Mobility: the ATN Concept

ATN BackboneATN TRD ATN TRD

ATN TRD Fixed ATNERD

Fixed ATNERD

Non-ATN RD

Home RD for airline B

Aircraft AERD

Aircraft BERD

Route to all aircraft

Specific Route to A

Specific Route to B


Ground Routing Aggregation

TRD

FixedERD

TRD

European ATN Island

TRD

FixedERD

TRD

North-AmericanATN Island

Route to 47B137

Prefix=47B137

Prefix=47B13701

Prefix=47B13702

Prefix=47B13703

47B1370201

47B1370202

Route to 47B142

Prefix=47B14201

Prefix=47B14202

Prefix=47B14203

47B1420201

47B1420202

Prefix=47B142


The SITA ATN Service The SITA ATN Service ArchitectureArchitecture

Note SATCOM has currently not been validated.


Agenda

Introduction

CPDLC

ATN

VDLm2

Synthesis


Reminder: ACARS-based Data Link

VHF

ACARS MU

RGS

GES

SITAs DSPAirlines Operations Centre

ACC

Ground DataNetwork


ACARS Status

Strength Globally available Large fleet of equipped aircraft, standard equipage in new

airframes Strong support for AOC application

Weaknesses Low data rate: Max throughput is 300 bps Near capacity saturation Quality of Service less suitable for ATM applications

New data link technology required for ATS: VDLm2


VDL Mode 2

Standardised ICAO SARPs Originally proposed in May 1994 Adopted in March 1996 Published in Nov 1997 Adjacent channel emissions modification in March 2000

Provides 31.5 kbps data rate Uses Differential 8-Phase Shift Keying


VDL Mode 2 Modulation

1 1 0 1 1 0 1 0

1

0

0

RaisedCosineFilter

1) Bit scramblingapplied: clock recovery

2) Bitstream is groupedInto 3-bit symbols

3) One of 8 phase changesSelected for transmission:Difference between current andprevious phases

4) Pulse shaping

Symbol transmission rate is 10.5 kps, 3 bit per symbol = 31.5 kbps


VDLm2 Protocol Layers

8208

AVLC

D8PSK

8208

AVLC

D8PSK

DTE DCE


AVLC Specifics

CSMA = Multipoint Configuration Frames

XID used for Data Link Establishment & Management

I, RR & SREJ for Normal Data Transfer

UI for Broadcast Data Transfer DISC for Data Link Termination FRMR, DM & UA for Protocol Errors

C C C

C C


The GSIF

Periodically Transmitted by Ground Station Announces Ground Stations Existence and Capabilities

Conveys Optional Function Support Timer Values Frequencies Supported Airport Coverage Nearest Airport ID ATN Router NETs Ground Station Location Service Operator Identity (Implicit in Source Address)


VDLm2 Data Link Establishment

XID_CMD_LE

XID_RSP_LE

LE always Air Initiated Aircraft VME sees GSIF Aircraft issue a LE command in a

XID frame Ground stations returns a LE

Response in a XID Frame

GSIF


MAC, AVLC, 8208

Media Access Control Carrier Sense Multiple Access (CSMA) No prioritisation Any user can transmit at any time

Data Link Control Aviation VHF Link Control (AVLC) Detect and recover from transmission error Source/Destination identification Link use management

ISO 8208 Virtual Circuits (multiple concurrent data streams) End-to-end error control and flow control


VGS Technology

Antenna (up to 4 antennas)

VHF Data Radios (VDR)

VHF Ground Computer (VGC)

Local maintenanceUninterruptible Power Supply

(UPS)

GPS source

Power SupplyRemote Maintenance

Ground Network

Each radio should be configurable to handle ACARS or VDL Mode 2


Agenda

Introduction

CPDLC

ATN

VDLm2

Synthesis


Summary: Subnetwork Connection Establishment

GSIF

Join

XID_CMD_LE

XID_RSP_LE

8208 Call RequestI-Frame 8208 Call Request

8208 Call Confirm

8208 Call Confirm I-Frame

AirborneRouter

AirborneVDL

VDL GroundStation

Air/GroundRouter


Summary: IDRP and Transport Connection

I-FrameOpen BISPDU (in8208 packet)

I-Frame

AirborneRouter

AirborneVDL

VDL GroundStation

Air/GroundRouter

Open BISPDU (in8208 packet)

FMSystem

I-FrameUpdate BISPDU (in8208 packet)

I-Frameupdate BISPDU (in8208 packet)

FEPOpen BISPDU(in 8208 packet)

Open BISPDU (in

8208 packet)

Update BISPDU (in8208 packet)

Update BISPDU (in

8208 packet)

I-FrameCR TPDU(in CLNP packet)8208 Data

8208 Data

CR TPDU(in CLNP packet)

CC TPDU8208 DataI-Frame8208 DataCC TPDU(in CLNP packet)

cpdlc atn vdlm2 tutorial

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