STUDY ON AIR TO GROUND DATALINK COMMUNICATION

ACARS

HISTORY

• Airborne Communication

• VHF Voice communications

• AM

• Telex formats

INTRODUCTION

• ACARS: Aircraft Communications Addressing and Reporting System

• Full-duplex datalink

• Effort to improve data integrity and reduce crew workload

• Introduced in 1978

• 2400 baud rate

WORKING

• An on board person or system can create a message and send it via ACARS to a

system or user on the ground, and vice versa.

• Remote Ground Stations

• VHF Subnetwork: Line-of-sight propagation

• HF Subnetwork: Continental Coverage

• Satellite Communication: World-wide coverage

USES

• OOOI Events: Out of the gate, Off the ground, On the ground, and Into the gate

• ADS : Automatic Dependent Surveillance – Position reporting of a/c

• Flight management system interface: Flight plans and weather conditions etc.,

• Maintenance data download: Operational performance

• Interactive crew interface: Crew communication

• Online black-box

EXAMPLE MESSAGE

A typical ACARS VHF transmission.

Mode A

Aircraft B-18722

Ack NAK

Block id 2

Flight CI5118

Label B9

Msg No. L05A

Message /KLAX.TI2/024KLAXA91A1

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WHAT ARE WE USING TODAY?

• Aircraft Communication Addressing and Reporting System (ACARS)

• Character based transmissions

• 2400 bps transmission speeds

• In use since 1978

• Current statistics (ARINC)

• Service provided through 196 stations

• System is reaching it’s capacity in U.S./Europe

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PROBLEM

• Growing number of ACARS aircraft

• Potential new demand from new participants

• Civil: Large Scheduled (Regional), Cargo, and Business

• Military: Non-Tactical Aircraft, Air National Guard

• Estimated potential at larger scale

• Increasing number of data link applications

• Aircraft Performance

• Crew Management

• In-flight Operations

• Many areas are already experiencing congestion on en route frequencies

SOLUTION

• Managing spectrum congestion and availability will be a growing and

continuing concern for the airline industry.

• Over the next 20 years, ACARS will be superseded by the Aeronautical

Telecommunications Network (ATN) protocol for Air Traffic Control

communications and by the Internet Protocol for airline communications.

Presented By:V SHYAM PRASADA RAOshyamforever@live.com