www.dlr.de Chart 1 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 LDACS1 L-band Compatibility and Extension Towards Navigation Michael Schnell, DLR B. Belabbas, B. Elwischger, U. Epple, N. Franzen, J. Furthner, S. Gligorevic, N. Schneckenburger, D. Shutin, M. Süß, M. Walter DGLR Workshop Datenlink-Technologien für bemannte und unbemannte Missionen
www.dlr.de Chart 2 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Motivation Future Communication Infrastructure (FCI) ATM Renovation SESAR NextGen Air-traffic Increase New ATM Concepts New Technologies More Efficient Technologies Digital Communications Digital Communications FCI: AeroMACS, SatCom, LDACS + Networking of Data Links
www.dlr.de Chart 3 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Motivation Future Communication Infrastructure (FCI) Networking the Sky satellite-based communications air-air communications ground-based communications LDACS communications in and around airports ground network
www.dlr.de Chart 4 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Outline LDACS1 System Design (Haindl, FREQUENTIS AG) LDACS1 Potentials Salzburg University DLR L-band Compatibility Extension Towards Navigation iad GmbH, BPS Rohde & Schwarz Future Work
www.dlr.de Chart 5 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 LDACS1 Potentials Why not a COTS Solution? - The technology for broadband data link communication is available - Current standards with their different profiles cover a huge application range, see e.g. WiMAX or LTE Potential candidate systems - Current COTS solution tend to disappear within a short timeframe; much too short for product cycles in aviation - Technology no longer supported - Chip sets no longer available - Availability of aeronautical spectrum resources Aviation specific solution required LDACS1 inlay system
www.dlr.de Chart 6 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 LDACS1 Potentials Characteristics and Extensions - 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): 115 kbit/s (70 kbit/s) - LDACS1 foresees quality-of-service - Fast access to resources, both forward and reverse link - Low delays for application - Different priorities for different applications - Highly flexible solution with Long-term Evolution capability of LDACS1 - Like LTE, extension towards higher performance - Scalability of physical layer design (OFDM) - Integration of navigation functionality into LDACS1
www.dlr.de Chart 7 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility LDACS1 Lab Demonstrator - LDACS1 lab demonstrator for L-band compatibility testing - First compatibility tests performed together with DFS RF Frontend Rx A/D Host PC Tx D/A Baseband Processing Up-/Down-Conversion - Tx unit: Complete implementation according to specification - Rx unit: Data grabber and offline software receiver
www.dlr.de Chart 8 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility LDACS1 Impact onto DME Measurement Set-up LDACS1 DME
www.dlr.de Chart 9 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility LDACS1 Impact onto DME Measurement Set-up Co-site Less Relevant No Continuous Transmission G2A Not Considered Yet Cell Planning LDACS1 DME
www.dlr.de Chart 10 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility LDACS1 Impact onto DME Measurement Results G2A Time to Acquire [s] 4.5 4 3.5 3 2.5 2 DME900 - f = 0 khz DME900 - f = 500 khz DME900 - f = 1000 khz 1.5 1 SIR -50-40 -30-20 -10 0 10 20 30 22 db Signal to Interference Ratio [db]
www.dlr.de Chart 11 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility LDACS1 Impact onto DME Measurement Results Co-site 7 6 DME900 - f = 0 khz DME900 - f = 500 khz Time to Acquire [s] 5 4 3 2 1 DC 0 10 20 30 40 50 60 70 5-10% LDACS Duty Cycle [%]
www.dlr.de Chart 12 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 L-band Compatibility DME Impact onto LDACS1 - Measurements with lab demonstrator Scenario SIR [db] PPPS BER unc BER cod G2A -72 2700 4.4 % 0 Co-site -110 100 2.9 % 0 A2G -63 1000 1.2 % 0 DME: Large Interference Power DME: Pulsed Interference Interference Mitigation: Pulse Blanking Coding - Cell planning for European airspace - Cells can cover twice the current traffic - Only half of available channels required Huge potential for future growth
www.dlr.de Chart 13 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Basic Concept GNSS Back-up (APNT) - The LDACS1 communication system is a cellular network - Ground stations (GS) are separated in frequency - GS are synchronized to each other GS3 GS4 GS1 GS2 Continuously transmitting LDACS1 ground stations act as pseudolites
www.dlr.de Chart 14 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Performance Bounds on Ranging With LDACS1 10 4 Schmidl-Cox Synchronization Freq. Domain: Synchronization Symbols Time Domain: Synchronization Symbols CRLB: Synchronization Symbols Mean Range Error [m] 10 3 10 2 10 1 ~4.1 m ~230 m 10 0 ~4.1 m 0 5 10 15 20 25 Carrier to Noise Ratio [db]
www.dlr.de Chart 15 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Flight Measurement Campaign Elevation [m] 12000 10000 8000 6000 4000 2000 0 0 20 40 60 80 100 Flight Time [min] Power Distance, km from/to B C D LDACS D LDACS C LDACS B LDACS A <960MHz 962MHz 965MHz 975MHz f A 60 50 30 B 30 28 C 43
www.dlr.de Chart 16 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Ranging Results for Station A 24 Estimated Range 22 Range, km 20 18 16 Estimated range Filtered estimate Interpolated GPS range GPS range measurement 210930 210960 14 210870 210900 GPS seconds Flight Segment
www.dlr.de Chart 17 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Ranging Results for Station A Zoom-in 16400 Estimated Range (Zoom-in) 16350 16300 16250 Range, meters 16200 16150 16100 16050 16000 Estimated range Filtered estimate 15950 Interpolated GPS range GPS range measurement 210896,7 210897,7 210898,7 210899,7 GPS seconds
www.dlr.de Chart 18 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Extension Towards Navigation Ranging Results for Station A Error Distribution Filtered OFDM ranges Snapshot length: 80s Traveled distance: 9 km 6000 99,3% Ranging performance: σ = 10 m µ = 4.1 m Counts 5000 4000 3000 2000 1000 0-40 -30-20 -10 0 10 20 30 40 Range error, meters
www.dlr.de Chart 19 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Conclusions and Future Work - L-band communications is a crucial part of the FCI - LDACS1 is well-suited to serve modern ATM applications - Highly flexible and scalable - Possible extension for long-term evolution - First compatibility investigations (LDACS1 DME) are very promising - 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 to validate navigation performance - We will further develop both LDACS1 and an APNT approach for GNSS back-up based on LDACS1
www.dlr.de Chart 20 DGLR Workshop > LDACS1 L-band Compatibility and Extension Towards Navigation > Michael Schnell > 21.03.2013 Thank You!