current status of ldacs development first meeting...current status of ldacs development michael...
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![Page 1: Current Status of LDACS Development first meeting...Current Status of LDACS Development Michael Schnell German Aerospace Center (DLR) • Chart 1 ICAO Communications Panel 1-5 December](https://reader034.vdocuments.mx/reader034/viewer/2022042105/5e82e495a9ca4a21014fa522/html5/thumbnails/1.jpg)
Current Status of LDACS Development
Michael Schnell German Aerospace Center (DLR)
www.DLR.de • Chart 1
ICAO Communications Panel 1-5 December 2014 Presentation of IP01
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Motivation The Future Communications Infrastructure (FCI)
www.DLR.de • Chart 2
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Motivation Air/Ground Communications
www.DLR.de • Chart 3
From Voice to Data …
DSB-AM: Analog Voice
VDL2: Kind of SMS
… to Internet and SWIM
LDACS: Connectivity
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Outline
www.DLR.de • Chart 4
Achievements and Current Status of LDACS LDACS1 Extension Towards Navigation Conclusions Open Issues
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Achievements and Current Status of LDACS Brief Review of LDACS - L-band Digital Aeronautical Communications System (LDACS) is the
future ground-based communications link within the FCI
- Two proposals: LDACS1 and LDACS2
- Deployment in L-band (960-1164 MHz)
- L-band already heavily used by - Aeronautical navigation services - Aeronautical military communications systems
- Different deployment options - Use only lower part of L-band, 960-978 MHz (LDACS2) - Use lower and upper part of L-band, 960-978 MHz / 1150-1157 MHz - Slight rearrangement of L-band assignments for radar navigation - Inlay scenario (preferred approach for LDACS1)
www.DLR.de • Chart 5
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Achievements and Current Status of LDACS Brief Comparison Between LDACS1 and LDACS2 - LDACS1 can utilize more spectrum in L-band due to inlay approach; no
reorganization of spectrum assignments required
- LDACS1 is the broadband LDACS proposal (fivefold bandwidth) making available considerably more capacity
- LDACS1 applies modern communications concepts (OFDM)
- LDACS1 considerably more mature than LDACS2 - Continuous development since 2007 - Detailed evaluations of PHY and MAC layer - Receiver concept with strong robustness against interference - Numerous publications (> 30 since 2007) - Several demonstrators/prototypes available
- Europe: DLR, Frequentis AG, Rohde & Schwarz - Japan: ENRI, GNU radio implementation - China: BUAA, hardware implementation, flight testing
www.DLR.de • Chart 6
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Achievements and Current Status of LDACS Potentials of LDACS1
www.DLR.de • Chart 7
- LDACS1 enables high-capacity aeronautical communications - Min. net data rate (FL+RL=overall): 291+270 = 561 kbit/s - Max. net data rate (FL+RL=overall): 1.32+1.27 = 2.59 Mbit/s - Well suited to serve modern ATM application and future needs
- Comparison with LDACS2 (overall): 70-115 kbit/s
- LDACS1 is highly flexible and scalable, enables long-term evolution - OFDM based physical layer - Scalability towards higher data rates
- LDACS1 foresees quality-of-service - Fast access to resources and low delays for application - Different priorities for different applications
- LDACS1 enables integration of navigation functionality
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Achievements and Current Status of LDACS LDACS1 Work in Europe
www.DLR.de • Chart 8
SESAR JU Project P15.2.4 ATM Research
in Europe
LDACS1 Demonstrator Developed by FRQ
Compatibility Testing at DFS labs
SESAR 2020? Mature Technology, Update Specification
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Achievements and Current Status of LDACS LDACS1 Work in Germany
www.DLR.de • Chart 9
DLR Internal Projects
Receiver Optimization Interference Mitigation
Receiver Concept
Demonstrator Complete Transmitter
Software Receiver
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Achievements and Current Status of LDACS LDACS1 Work in Germany
www.DLR.de • Chart 10
ICONAV German National
Project with R&S as Industry Lead LDACS-COM
Hardware Implementation Including Security
LDACS-NAV DLR Internal Project
MICONAV Follow-on Project
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Achievements and Current Status of LDACS LDACS1 Work Outside Europe
www.DLR.de • Chart 11
Japan ENRI (Electronic Navigation Research Institute)
LDACS1 Demonstrator Based on GNU Radio Hardware Implementation
China Beihang University (aka BUAA)
National Key Laboratory of CNS/ATM Theoretical Studies and Simulation on LDACS1
Demonstrator Implementation Preliminary Flight Tests in (May 2014)
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LDACS1 Extension Towards Navigation Navigation Functionality for APNT - What is APNT? Alternative Positioning Navigation and Timing - Why APNT? For the GNSS failure case!
www.DLR.de • Chart 12
GNSS becomes primary navigation means
Navigation services require high performance
for all phases of flight Large distance
SAT-aircraft, GPS easily jammed
Newark Liberty Int’l Airport
“GPS Jammer” Personal Privacy
Device
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LDACS1 Extension Towards Navigation LDACS1 as Pseudolite System
www.DLR.de • Chart 13
Continuously transmitting LDACS1 ground stations
act as pseudolites: “GPS on Ground”
Aircraft performs pseudo-range measurements towards LDACS1 ground station
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LDACS1 Extension Towards Navigation Performance Bounds on Ranging With LDACS1
www.DLR.de • Chart 14
0 5 10 15 20 25
100
101
102
103
104
Carrier to Noise Ratio [dB]
Mea
n R
ange
Erro
r [m
]
Schmidl-Cox SynchronizationFreq. Domain: Synchronization SymbolsTime Domain: Synchronization SymbolsCRLB: Synchronization Symbols
~4.1 m
~4.1 m
~230 m
Theory: • Cramer Rao Lower Bound (CRLB) • Mean range error several meters
Simulations: • Slight adjustments to sync. • Theoretical bound achievable
@ reasonable C/N
Reality: • Performance in real environment? • Flight measurement campaign!
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LDACS1 Extension Towards Navigation Flight Measurement Campaign
www.DLR.de • Chart 15
f/MHz 960 970
GSM
975 965 962
TAC
AN
LDAC
S A
LDAC
S B
LDAC
S C
LDAC
S D
Three flight levels: • FL100 • FL280 • FL380
LDACS – L-band Digital Aeronautical Communications System > Michael Schnell > October 2014
30 km
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LDACS1 Extension Towards Navigation Range Estimation Results – Whole Flight
www.DLR.de • Chart 16
-60 -40 -20 0 20 40 600
0.02
0.04
0.06
0.08µ = 6.7 mRMSE = 15.2 m
Estimation Error [m]
Pro
babi
lity
µ = 6.7 m RMSE = 15.2 m
Raw range estimates,
averaged over 1 s time intervals
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LDACS1 Extension Towards Navigation Range Estimation Results – Whole Flight
www.DLR.de • Chart 17
-60 -40 -20 0 20 40 600
0.02
0.04
0.06
0.08µ = 6.7 mRMSE = 15.2 m
Estimation Error [m]
Pro
babi
lity
µ = 6.7 m RMSE = 15.2 m
Main error source: Multipath propagation
Main error source: Troposphere
Second campaign for channel sounding
Ranging algorithms: Maximum Likelihood Doppler Smoothing
Particle Filtering
Channel modeling
Tropospheric models available
Significant reduction of bias possible
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Conclusions
- LDACS1 is well-suited to serve modern ATM applications - High-capacity data link - Highly flexible and scalable
- LDACS1 has been considerably matured within the last years
- First compatibility investigations (LDACS1 DME) have been
performed
- LDACS1 offers an excellent opportunity for extension towards navigation - APNT service on top of communications infrastructure - Theoretical ranging performance in the order of meters - Measurement campaign validates navigation performance for APNT
www.DLR.de • Chart 18
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Open Issues
- Further L-band compatibility evaluations for LDACS1 - DME/TACAN, UAT, SSR Mode S - Military communications systems (JTIDS)
- Development of deployment concept for LDACS1
- Development of a migration strategy from VDL2 to LDACS1
- Development of final LDACS1 specification including technology
amendments as required and initiation of standardization
- Development of fully functional LDACS1 prototype and flight testing
www.DLR.de • Chart 19
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www.DLR.de • Chart 20
Thank You! More about LDACS1
www.ldacs.com