[PPT] - Towards Selective Addressing of Aircraft with Voice Radio Watermarks PowerPoint Presentation

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Towards Selective Addressing of Aircraft with Voice Radio Watermarks

 Horst Hering, Konrad Hofbauer  EUROCONTROL Experimental Centre (EEC),

Bretigny, France

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Outline

 Introduction

 Aircraft Identification Tag (AIT) basics  AIT benefits

 Motivation for R&D

 Issues of the radio communication

 Proposed solution

 Selective PTT switch  Demonstrator  Experimentation

 Results and conclusion

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Introduction

 Air traffic guidance based on:

 Standardised voice radio communication

 VHF channels (118…133 MHz)  AM - modulation   technique known to be sensitive for disturbance - poor voice quality

 Party line concept

 One voice channel /sector  One controller  All aircraft  obligation for identification (down- & up-link) Voice Signal

(pilot/ ATCO)

VHF Transmitter PTT Switch VHF Receiver Voice Signal

(ATCO /pilot)

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Aircraft Identification Tag*

 FM broadcast radios

 Radio Data System - RDS identify radio channel for listener

 Watermark techniques for conventional ATC radio channels

 Embedding digital data in analogue speech  Not noticeable in transmitted speech

* H. Hering, M. Hagmueller, G. Kubin, “Safety and security increase for air traffic management through unnoticeable watermark aircraft identification tag transmitted with the VHF voice communication”, in proceedings of the 22nd Digital Avionics Systems Conference (DASC 2003), Indianapolis, USA (2003)

Voice Signal

(pilot/ ATCO)

Watermark Embedder VHF Transmitter Signature

(Originator)

PTT Switch

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Aircraft Identification Tag

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

AIT Initial Feasibility Study*

 Deployment-driven requirements

 Rapid and simple deployment  Legacy system compliance  Bandwidth efficiency  Minimal aircraft modifications  Cost efficiency

 User-driven requirements

 Perceptual quality  Data rate  Real-time availability  Error rate  Maintaining established procedures  No user interaction

*AIT- Initial Feasibility Study, EATMP Info-centre, EUROCONTROL Brussels, Belgium (2006) (consortium: Sofreavia, Frequentis, Rockwell-Collins)

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Current AIT R&D

 Speech consists of segments with:

 periodic structure - voiced speech (vowel, semi-vowels and nasal sounds)  noise-like structure - unvoiced speech (most of the consonants)

 Watermarking in unvoiced speech*

 Advantages

 High perceptual quality  High data rate (capacity)  Ex.: Original signal  Ex.: Watermarked signal with 2000 bits per second

*K. Hofbauer and G. Kubin, “High-rate data embedding in unvoiced speech,” in Proceedings of the International Conference on Spoken Language Processing (INTERSPEECH), (Pittsburgh, PY, USA), Sept. 2006.

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Aircraft Identification Tag

 Benefits

 Call sign confusion and ambiguity

 “Mis-identification”

 Safety Threat

 Malicious messages

 Radio transmissions issued by unauthorized 3rd party

 Security Threat

 Increase ATCO’s situation awareness

 Visual stimuli reinforce audio hearing

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Motivation for R&D

High load of the radio communication channel

ver core Europe

 Small sectors (5…7 minutes fly through time)

 VOCALIS study*

 60 hours of voice communications  12 different French en-route sectors featuring heavy traffic periods

 Watching party line is a hard task for pilots

 Average of 324 speech acts per hour

 About 5 speech acts per minute

*L. Graglia et al., “VOCALISE: Assessing the Impact of Data Link Technology on the Radio Telephony Channel”, in proceedings of the 24th Digital Avionics Systems Conference (DASC 2005), Washington DC, USA (2005)

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Issues for the Radio Communication

 AIT  downlink of a digital aircraft signature for the ATCO to

increase safety and security

 Uplink of the aircraft address ???

  similar benefits for the aircrew

 Generation of an attention getter

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Proposed Solution

 Uplink the aircraft address via AIT   ATCO has to indicate the destination of each voice message

to the AIT system

  On board of the addressed aircraft an attention getter is created

Voice Signal

(ATCO)

Watermark Embedder VHF Transmitter Signature

(ATCO)

PTT Switch Address

(Destination)

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Selective PTT Switch Concept

 The selective PTT switch:

 Triggers the radio transmitter  Interacts with the ATM system to define the called aircraft address

Signature

(ATCO)

Voice Signal

(ATCO)

Watermark Embedder VHF Transmitter Address

(aircraft)

Selective PTT

ATM System

‘Mouse’ Position Last AC AIT

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Selective PTT Switch Logic

 Last aircraft calling in (AIT) is memorised for ~20 seconds  Physical PTT switch triggers a selective logic  Selective logic:

 Mouse cursor hovers above memorised aircraft

 this aircraft is called if PTT switch pressed

 Mouse cursor does not hover above an aircraft

 this memorised aircraft is called if PTT switch pressed

 Mouse cursor hovers above different aircraft

 this aircraft is called if PTT switch pressed  memorised unanswered aircraft is highlighted for 2 seconds

 Mouse cursor hovers above ‘Public’ call button

 all aircraft in the sector are called

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Selective PTT Switch

 Based on AIT watermark technology  Uplink voice messages with an embedded digital destination address

 Supports aircrew with automatic attention getter for ‘own’ radio messages  Benefits for on board safety  Benefits for the secured voice communication

 Implements digital features in analogue radio communication

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Selective PTT Switch Demonstrator

 Demonstrator setup

 Static air traffic situation (simulation screen shoot)  Animated with audio and visual cues

 Aircraft calling in  AIT highlighting of the aircraft calling in  Selective PTT switch representation

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Demonstrator Screen

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Calling Aircraft

 Demonstrator assumption: all aircraft AIT equipped  Blinking frame while aircraft is calling in

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Selective PTT Switch Pressed

 Calling LOT232 - aircraft that called in last  Calling YUBRZ - system reminds that LOT232 called last

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Demonstration/ Experiments

 12 operational experts of the EEC (ex-controllers)  From 8 different European countries  Period August 2007  Questionnaire “Selective PTT switch Concept - Usability”

 Based on an evaluated IBM computer usability questionnaire*

*J. R. Lewis, “IBM Computer Usability Satisfaction Questionnaires: Psychometric Evaluation and Instructions for Use”, International Journal

f Human-Computer Interaction, 1995 v.7 n.1 p.57-78

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Global Question

 Usage of the selective PTT switch requires change of the

current working procedures for the controller

 Selection of the called aircraft by hover the label

and

 Pressing the PTT switch

 Is this change of the working procedures acceptable for the

controllers ?

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Questions and Answers

1. Overall, I am satisfied with how easy it is to use this concept
2. It was simple to use this concept
3. I can effectively complete my work using this concept
4. I am able to complete my work quickly using this concept
5. I am able to efficiently complete my work using this concept
6. I feel comfortable using this concept
7. It was easy to learn to use this concept
8. I believe I became productive quickly using this concept
9. Whenever I make a mistake using the concept, I recover easily

and quickly

10. The information on-screen provided with this concept is clear
11. It is easy to find the information I needed
12. The information provided for the concept is easy to understand
13. The information is effective in helping me complete the tasks and

scenarios

14. The organization of information on the demonstrator screen is

clear

15. The interface of this concept is pleasant
16. I like using the interface of this concept
17. This concept has all the functions and capabilities I expect it to

have

18. Overall, I am satisfied with this concept

strongly agree strongly disagree

1 2 3 6 5 4 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

question Mean Standard Deviation (±1σ) Dominant/mode

Concept use Information quality Interface quality

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC

Result and Conclusion

 Interface usability results

 Overall satisfaction of the selective PTT switch concept :

2.49*

 Usage of the selective PTT switch :

2.38*

 Quality of the presented info :

2.35*

 Quality of the interface :

3.00*

 Globally the new working procedures with selective PTT switch are

acceptable

 Open ways for other com features (digital communication like)  AIT together with the selective PTT switch represent for analogue radios

a preliminary step towards digital end-to-end radio communication

*Scale : strongly agree = 1 ... neutral = 4 … strongly disagree = 7

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European Organisation for the Safety of Air Navigation

Long Term Investigations, EEC