VDL Mode 4 Airborne Architecture Study VM4AAS

1
VDL Mode 4Airborne Architecture Study(VM4AAS)

• Study Overview and Conclusions

E. F. Charles LaBerge, PhD Honeywell AES
Laboratory Communications Surveillance Center
of Excellence
Nikos Fistas EATMP / EUROCONTROL Communications
Surveillance Management Business Division
2
Presentation Overview

• PART I General information (ECTL)
• Scope, Objectives, Plan, Structure
• PART II Study Summary (Honeywell)
• Overview of work achieved (Work Packages 1 to 4)
• Conclusions
• Recommendations
• Next Steps

3
PART IGENERAL INFORMATION
4
VM4AAS scope

• Investigate airborne integration issues for VDL
  Mode 4, considering
• COM / SUR / COM and SUR applications
• Large / Small / Light a/c
• Forward-fit / Retrofit (digital and analogue)
  a/c

5
VM4AAS Objectives (contd)

• To
• provide answers to questions
• identify potential problems
• make recommendations
• contribute to decision making
• provide input/guidance to manufacturers
• considering current status and future trends

6
Study Background Information

• Performed by Honeywell
• Started in June 2002
• Finished October 2003
• Informal external review group (open to
  interested volunteers )

7
VM4AAS Deliverables
8
Deliverable Review Process
9
PART IISTUDY SUMMARY
10
VM4AAS Work Structure

• Preparatory work
• WP1 - D1 Assumptions and Baselines
• WP2 - D2 Identifications of Requirements
• Investigations
• WP3 - D3.2 RF Interference Analysis
• WP3 - D3.1 Avionics Architectures
• WP4 - D4 Implementation and Transition

11
Work Package 1 Assumptions and Baselines

• Preliminary work to form the foundation for WP3
• Establish assumptions
• Establish baselines

12
WP1 Assumptions

• VDL Mode 4 is acceptable to support applications
• CDL only
• SDL only
• combined CDL and SDL
• 15 other assumptions in 3 broad groups
• Group 1
• SSR
• Mode-S-based ACAS
• Group 2
• Simultaneous VHF Communications
• Group 3
• 8.33 kHz VHF Voice will be required throughout
  the study period

13
WP1 Aircraft Classes

• Large take-off mass gt15,000 kg
• (Citation X, G-IV, ERJ, Airbus, Boeing)
• Small 5700 kg lt take-off mass lt 15,000 kg
• (King Air 350, most Citation)
• Light take-off mass lt 5700 kg
• (Cessna 172, King Air C90B)

14
WP1 Equipment Baselines (1)

• Communication
• VHF Voice (DSB-AM) x 2
• ACARS or Mode 2
• Simultaneous operation of voice and data link
• Navigation
• GNSS
• ILS (Localizer and Glideslope)
• VOR

15
WP1 Equipment Baselines (2)

• Surveillance
• Mode S Transponder 1
• Mode S Transponder 2 or Mode C
• ACAS Mode S Interrogator (Large Small)
• CDTI

16
Work Package 2Identification of Requirements

• Identify general functional requirements
• Identify internal interfaces
• Identify external interfaces

17
WP2 Internal Interfaces

• Interconnections
• VDLM4 to and from other avionics
• Data Flow Diagrams
• Data Dictionary
• Precision Time Interface (PTI)
• CONCLUSION
• Only PTI and baseband interface issues are unique
  to VDL Mode 4 compared to any other CDL/SDL
  modem technology

18
WP2 Context-Level DFD

• An example Level 1 - external interactions

19
WP2 External Interface Issues

• RF Interference to/from other avionics
• Focus on same-aircraft or co-site problems
• Detailed study in WP3.2
• Derived work on integrity, availability, and
  continuity of service
• Traffic Loading estimates for 2015 based on
  MACONDO

20
Work Package 3.2Interference Analysis (1)

• RF Interference Issues
• VHF Communications
• Sources DSB-AM, VDL Mode 2, VDL Mode 4
• Victims DSB-AM, VDL Mode 4, Localizer, VOR,
  VDB, Glideslope
• Large, Small, Light Aircraft

21
Work Package 3.2Interference Analysis (2)

• Same-side, Opposite-side antennas
• Link-budget analysis using published standards or
  carefully documented assumptions
• 3 issues Desensitization, Off-Channel Emissions,
  RF (front end) Saturation

22
WP3.2 VHF COM I/f Problem
23
WP3.2 Key Assumptions

• MOPS -87 dBm reference signal level
• Emissions levels
• DO-186A (Voice), DO-281/ED-92 (Mode 2), ED108
  (Mode 4)
• Assumed noise floors
• Using ARINC 716 isolations
• MOPS adjacent channel rejection
• ACR is a desensitization spec
• Figure of merit Es/N0 or S/P

24
WP3.2 3 VHF-on-VHF i/f scenarios

• Voice on digital
• RF Saturation
• IF Desensitization
• Off-channel emissions (residual phase noise)
• Digital on voice
• RF Saturation
• Squelch break
• Audio S/P concerns
• Digital on digital
• RF Saturation
• Desensitization IF
• Off-Channel emissions (residual phase noise)
• Potential duty-factor mitigation

25
WP3.2 Voice on digital i/f

• Mechanism
• Primarily phase noise and RF saturation
• IF desensitization is lesser effect
• Challenges
• 100 voice duty factor
• Voice transmitter 46 dBm (40 W)
• Mitigations
• Better in-band filtering for digital receiver
  (IF)
• Better-than-MOPS phase noise of voice
  transmitter
• Increased isolation
• Channel separation
• Robust application protocols
• Clear continuity definitions
• Reduced use of AM voice as data use increases

26
WP3.2 Digital on voice i/f

• Mechanism
• Primarily phase noise and RF saturation
• IF desensitization is lesser effect
• Challenges
• 100 voice duty factor
• Better than MOPS sensitivity of most AT receivers
  
• Mitigations
• Better than MOPS emissions for digital
  transmitter
• Increased isolation
• Channel separation
• Constrain protocols to short pulse widths
• Consider cooperative suppression during
  transmissions

27
WP3.2 Digital on digital i/f

• Mechanism
• Primarily phase noise and RF saturation
• IF desensitization is lesser effect
• Challenges
• Multiplicity of antennas/limited isolation
• Low-noise figure designs with FM protection
• Mitigations
• Better emissions for digital transmitter
• Better-than-MOPS adjacent channel rejection
• Increased isolation
• Channel separation
• Robust applications and protocols
• Clear continuity definitions

28
WP3.2 Off-channel Desensitization
29
WP3.2 RF Saturation

• New result (not in original WP3.2)
• Supported by Boeing/Honeywell testing (Sept 2003
  - data not yet released)
• May be the limiting factor!

30
Work Package 3.1Architecture Descriptions

• 11 different forward fit architectures
• 1 radio retrofit architecture
• Recommendations
• Multi-function VHF radio
• 8.33 kHz, 25 kHz, VDLm2, VDLm4
• Independent transmit and receive capabilities
• Baseband control and flexibility

31
WP3.1 requirements and constraints

• Integrity
• RMER 10-6 to 10-8
• Continuity
• Loss of Continuity 1 x 10-5 to 5 x 10-4
• Availability
• Communication system MTBF 1000 days
• Surveillance system MTBF 1000 day

32
WP3.1 Architecture Candidate 5

• ARINC 750 form factor New VHF Digital Radio
  (NVDR)
• 4R1T, half duplex transceivers (not available
  today)
• High-speed baseband information sharing
• Independently reconfigurable R/T capabilities

33
WP3.1 Architecture Candidate 9

• Remote mount high-end B/RA New VHF Digital Radio
  (NVDR)
• 4R1T, half duplex transceivers (not available
  today)
• High-speed baseband information sharing
• Independently reconfigurable R/T capabilities

34
WP3.1 Architecture Candidate 10

• Retains existing analog voice radio for GA
  aircraft
• Small form factor (panel mount?) NVDR
• 4R1T, half duplex transceivers (not available
  today)
• Independently reconfigurable R/T capabilities
• Somewhat limited under certain failure conditions

35
WP3.1 Architecture Candidate 11

• Retains existing analog voice radio for GA
  aircraft
• Small form factor (panel mount?) NVDR
• 4R1T, half duplex transceivers (not available
  today)
• Independently reconfigurable R/T capabilities
• Somewhat limited under certain failure conditions

36
WP3.1 Other Products

• Allocation table showing how each transmitter and
  receiver is used
• Availability/continuity analysis tables
• Analytical Appendices

37
Work Package 4Implementation and Transition

• Relative normalized costs of installation in a
  variety of configurations
• Typical and Best-Case schedules

38
WP4 Summary of Relative Costs
39
WP4 Serial Task Schedule
40
WP4 Aggressive Schedule
41
Work Package 5 Final Report Summary

• Summarize WPs 1, 2, 3.2, 3.1, and 4
• Review external comments
• Conclusions
• Recommendations
• Open Items and Future Work

42
WP5 Review of External Comments

• Comments critical of WP 3.2
• VHF Voice assumptions were too severe
• Worst-case and not statistical analysis
• Not supported by field data and/or trial
  experience
• Comments about cost analysis with lack of benefit
  analysis
• Comments about intermodulation
• Comments about saturation

43
WP5 Study Conclusions (1)

• Interference Problem
• VHF-on-VHF interference will exist
• VHF-on-VHF interference will prevent simultaneous
  voice and data usage (valid for any VDL Mode)
• Voice-on-VDL interference is more critical
• Only half-duplex is achievable
• Uplink data applications must be made
  sufficiently robust to sustain transfer delay due
  to downlink voice
• Technical mitigations are insufficient

44
WP5 Study Conclusions (2)

• Aircraft Integration Problem
• Recommended architectures are based on
  multi-function half-duplex VHF transceiver with 1
  TX and 4 RXs
• Recommended architectures require interconnected
  transceivers
• VDL Mode 4 specific integration issues limited to
  PTI and baseband connections

45
WP5 Study Conclusions (3)

• General
• VDL Mode 4 installation plans should be
  coordinated with ADS-B and/or advanced data link
  upgrades
• Simultaneous operation of multiple VDLs and voice
  should be avoided
• Relative installation costs Retrofit analog gt
  Retrofit Digital gt Forward fit

46
WP5 Study Recommendations (1)

• Investigate operational impact of VDL Mode 4
  interference to voice and vice versa to determine
  if and which applications can be supported
• Complete feasibility analysis (safety, ..) of
  recommended architectures and facilitate as
  appropriate the development of multi-function
  4R1T transceiver with
• 8.33/25 kHz analog voice, VDL Mode 2, VDL Mode 4
• common baseband coordination
• quasi-independent R/T functions
• Use VMAAS results as input to other efforts to
  complete VDL Mode 4 specific cost/benefit
  analysis (CBA) to support link decision
• Coordinate any aircraft upgrades with ADS-B and
  advanced CDL application upgrades

47
WP5 Open Items/Future Work (1)

• Assess operational impact of voice-on-data
  interference
• Adopt GFSK BER analysis as part of a standard for
  reference
• Adopt VDL Mode 4 link budget to level of detail
  comparable with other VDL data links

48
WP5 Open Items/Future Work (2)

• Perform or refine system-level cost benefit
  analysis based on relative costs provided by WP4
• Perform, publish, and publicize additional
  measurements of VHF-on-VHF interference effects

49
VM4AAS

• Remarks Questions
• More info and available draft deliverables
• www.eurocontrol.int/vdl4/architecture.html
• Comments and input welcome
• nikolaos.fistas_at_eurocontrol.int
• christophe.hamel_at_honeywell.com
• chuck.laberge_at_honeywell.com