1. EUROCONTROL Experimental Centre Absolute versus Relative Navigation Theoretical Considerations from an ATM Perspective Robert Graham, Eric Hoffman, Christian Pusch, Karim Zeghal ATM Seminar 2003

2. EUROCONTROL Experimental Centre Outline Introduction New trends in ATM Current ATM Practices Layers and loops Discussion Conclusion

3. EUROCONTROL Experimental Centre New Trends in ATM since the 80’s: 4D Trajectories (4D absolute navigation) GARTEURCTAS PHARE Boeing ATM AFAS... since the mid-90’s: ASAS (3D relative navigation) Freer FlightFree Flight MA-AFASDAG-TM MFF... … and conceptual mixtures ICAO ATMCP - key role of 4D traj’s plus cooperative separation DAG-TM - CTAS elements plus self-spacing for merging etc AFAS vs MA-AFAS EC FP6 C-ATM

4. EUROCONTROL Experimental Centre Current Practices Procedural Control discrete reports: reporting points + time estimates  “4D objects” tools: strip displays (En-Route CCs), plotting charts (Oceanic), railway-like charts (former Soviet block) similarity for flight deck: TIBA  separation provided over estimates Radar Control continuously updated, time correlated geographical representation of traffic … but: no (or little) representation of future situation tools: CWP (plus: speed vectors, MTCD, ERATO, URET, AMAN  info on future situation) similarity for flight deck: visual separation (VMC clearance)  separation provided on current position

5. EUROCONTROL Experimental Centre Impact of New Concepts? To understand  Layers and Loops

6. EUROCONTROL Experimental Centre Layers and Loops Air  aircraft control theory  for human interactions (eg Billings, 1997) Ground  J. Villiers (1968): - flow management layer controls sector load - procedural control layer filters traffic for radar controller - radar control layer solves separation problems - accident layer should show the smallest possible probability  P. Schuster (2000) added to a/c loops an ATC loop  A. Haraldsdottir et al. (2000) refined this approach further...

7. EUROCONTROL Experimental Centre Layers and Loops /2 aircraft control safety net ~1 min ground / air tactical control ~5 min sector / flight planning ~10 min tactical flow management ~30 min vectors clearances FCU inputs planned flow rates approved handoffs, FMS inputs aircraft state ACAS / STCA FPLspilot clearance request negotiate handoffs planning separationaircraft & safety tactical flow management system feedback communication

8. EUROCONTROL Experimental Centre … 4D Trajectories ? trajectory trajectory negotiation

9. EUROCONTROL Experimental Centre 4D Trajectories /2 sole object used as reference for all layers (except safety) reinforces planning layer(s) separation strategies (expressed in relative position etc) require costly conversion (tools), and, … cannot be built incrementally (taking into account the evolution of the situation) trajectory prediction both in FMS and on ground - consistency ? trajectory negotiation and bandwidth ?  enables tactical flow mgt  empowers planning functions but: loss of reactivity in tactical layer

10. EUROCONTROL Experimental Centre … ASAS ? aircraft state ASAS

11. EUROCONTROL Experimental Centre ASAS /2 focus on separation loop - no influence on other layers (planning ??) reduction of executive controller workload:  tasks assigned to flight deck (or to (an)other controller(s) or automated) shift in time horizon for controller and flight deck etc to lesser criticality (lower frequencies) … and thus greater anticipation for both controller and flight crew the separation loop is split between controller (lower) and pilot (higher frequencies)  increase of controller availability  stepwise implementation easy but: local by nature

12. EUROCONTROL Experimental Centre Current Situation vs ASAS frequency / time criticality magnitude executive controller flight crew Planning Aircraft & Safety Separation Planning Aircraft & Safety Separation executive controller flight crew magnitude frequency / time criticality Bode diagrams: Co-Space Examples Co-Space … 

13. Delegation of Spacing Tasks from Controller to Flight Crew AF096BL, behind target, merge to ATN to be 12Nm behind ATN target AF096BL, select target 1234 Target 1234 identified, AF096BL 4Motivation: increase of controller availability through a reorganisation of tasks between air and ground 4Constraints: consider current roles and working methods (human) & keep it as simple as possible (technology) 4Starting point: analogy with visual separation, but no transfer of separation responsibility (PO-ASAS spacing category) 4Applications: sequencing in terminal areas and crossing in en-route 4Use of airborne surveillance (ADS-B, TIS-B) and additional avionics (CDTI, ASAS)

14. Past Experiments 4Human in the loop experiments to assess acceptability, impact on activity and outcomes (1 air/ground, 3 ground, 2 air) (23 controllers over a total duration of 9 weeks; 15 airline and test pilots over a total duration of 10 days) 4Impact on controller activity –Building of the sequences anticipated and relief of maintaining these sequences (instructions) –Controllers can still concentrate where the sequences need to be built (eye- fixations)

15. EUROCONTROL Experimental Centre Current Situation vs ASAS frequency / time criticality magnitude executive controller flight crew Planning Aircraft & Safety Separation Planning Aircraft & Safety Separation executive controller flight crew magnitude frequency / time criticality Remember...

16. EUROCONTROL Experimental Centre The “Best of Two Worlds” 4D absolute - flow management and complexity reduction 3D relative - separation provision through a more “fuzzy” type of trajectory (larger boundaries of the “tube”) tactical changes within boundaries  combine the two concepts... make them complementary !

17. EUROCONTROL Experimental Centre Airbus Layers CREW (Monitoring) CREW (Controls) Data Link (ATC) Flight definition >10mn ATM System FDPS, CFMU, ARR/DEP Manager ~1/2 sec ~10 sec ~1mn A/C Control: Position /Centre of Gravity A/C Guidance: Centre of Gravity / trajectory A/C Navigation: Position (4D) / Route Guidance Flight Management Flight Control Sensors ADIRS,RA,ILS/MLS, (D)GPS,Radio NAV Separation DomainTactical DomainTraffic DomainStrategic Domain Collision Avoidance + Data Link Communication VDL, (HFDL, SATCOM)Mode A,C,S Voice VDL M4, Mode S(2), UAT Situational Awareness Data Base ADS-B Ground Monitoring Radar STCAMTCD