4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASAS LC&P Applications in Radar Airspace: Operational Scenario Example and Fast-Time Simulation Results Thierry Miquel and Philippe Louyot DSNA, Toulouse, France John Anderson and Colin Goodchild University of Glasgow, UK

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational Procedure Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational Procedure Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASAS Resolution Manoeuvres Finite time-horizon (look ahead time 5-10 minutes) Lateral manoeuvre requirement only Third-party aircraft assumed isolated from ASAS designated pair Two well-established resolution manoeuvre classes have been assessed –Turning point manoeuvre –Offset manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASAS Resolution Manoeuvres Turning point manoeuvre –Minimizes the number of resolution manoeuvre stages –May be achieved through autopilot lateral functionality

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASAS Resolution Manoeuvres Offset manoeuvre –May be compatible with Flight Management System (FMS) functionality –A track alteration of 30 degrees has been assumed

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational Procedure Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Phases Set-up Phase Identification Phase Clearance Phase Execution Phase Termination Phase Controller Flight crew Set-up Phase

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example ATCO: CSA6662 For Lateral Crossing, identify Target AF534 ATCO assesses the opportunity of ASAS lateral crossing manoeuvre Setup phase + Identification phase

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot: CSA6662 Identify AF534

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot: CSA6662 Target Identified AF534, two o’clock, 38NM

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example ATCO: CSA6662 Pass behind [AF534], report clear of traffic, then proceed to MOKDI Clearance phase

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot: CSA6662 Pass behind AF534 then proceed to MOKDI (Clearance entered and solution evaluated)

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Flight crew aligns aircraft track by means of the Flight Control Unit. Alternatively, the solution can be coupled to the FMS functionalities.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example ATCO: AF534BH for information you are under ASAS separation Execution phase

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot monitors the expected separation (by means of relative ground speed vector)

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Clearance aircraft near the Closest Point of Approach.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Clearance aircraft passed CPA and close to Clear of Traffic.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot: CSA6662 clear of traffic, proceeding to MOKDI

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example ATCO: Roger, CSA6662, (instruction) ATCO assesses that separation at COT is OK and resumes responsibility for separation Termination phase

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Operational Procedure - Example Pilot: CSA6662 Proceeding to MOKDI End of ASAS – pilot resumes navigation monitoring.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational Procedure Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithm assessment Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Fast-Time Simulation Results Operational scenarios –Derived from pairwise crossing encounters in radar airspace in two adjacent sectors in southwest France:

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Fast-Time Simulation Results The selected radar set is modified such that aircraft are flying directly from the entry point to the exit point of the sector. Only encounters for which the initial separation is greater than 5 NM are considered (a total of 309 encounters). The clearance aircraft (ASAS equipped aircraft) is assumed to be the aircraft with the lowest airspeed Pass behind manoeuvres are simulated

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Navigation accuracy model: –The aircraft is assumed to follow a succession of waypoints. –The aircraft is assumed to be equipped with a track-hold autopilot. –Lateral positioning errors are included in the track- hold autopilot control to simulate the required 95% accuracy navigation positioning. Fast-Time Simulation Results

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Example of an encounter with 1 NM navigation error for both aircraft Fast-Time Simulation Results

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Fast-Time Simulation Results Simulations were performed for each of the selected encounters for each of nine wind fields and three navigation error categories: –Wind fields: {0 kts, 30 kts, 60 kts} x {0˚, 90˚, 180˚, 270˚} –Navigation positioning categories: {0, 0.3, 1} NM Focus on the set of uncontrolled encounters for which the separation is lower than 5 NM (1086 encounters)

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational scenario example Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Minimum lateral separation Maximum cross track deviation Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Fast-Time Simulation Results The objective of the ASEP-LC&P algorithms is to achieve a prescribed minimum lateral separation (5 NM in this case) Two performance metrics are used to assess the ASEP-LC&P algorithms: –Minimum lateral separation achieved –Maximum cross-track deviation

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Fast-Time Simulation Results For each encounter/wind field/navigation accuracy scenario, each of the performance metrics was assigned to one of the bin sets: –Bin 1: the metric value is between 0 NM and 2 NM –Bin 2: the metric value is between 2 NM and 4 NM –Bin 3: the metric value is between 4 NM and 6 NM –… –Bin 7: the metric value is greater than 12 NM

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational scenario example Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Minimum lateral separation Maximum cross track deviation Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Minimum lateral separation –No lateral crossing manoeuvre Minimum lateral separation Percentage of encounters per bin category

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Minimum lateral separation –No lateral crossing manoeuvre Minimum lateral separation Percentage of encounters per bin category

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Minimum lateral separation –No lateral crossing manoeuvre Minimum lateral separation Percentage of encounters per bin category

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Turning point manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Turning point manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Turning point manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Offset manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Offset manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Percentage of encounters per bin category Minimum lateral separation –Offset manoeuvre

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Example of unresolved conflict: –Despite a separation of 19.4 NM at the beginning of the encounter, the two aircraft cross at 2.3 NM. –This example basically shows that if the clearance is issued late, the radius of turn may not be sufficient to enable the clearance aircraft to correctly perform the lateral crossing manoeuvre.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational scenario example Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Minimum lateral separation Maximum cross track deviation Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Maximum cross-track deviation –Turning point manoeuvre Percentage of encounters per bin category Maximum cross-track deviation

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 ASEP-LC&P Algorithms Assessment Maximum cross-track deviation –Offset manoeuvre Percentage of encounters per bin category Maximum cross-track deviation

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Contents ASAS Resolution Manoeuvres Operational scenario example Fast-Time Simulation Results –Operational scenarios –ASEP-LC&P algorithms assessment Conclusions

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Conclusions Two well-established resolution manoeuvre classes have been investigated using a state- based geometric resolution algorithm: –Turning point manoeuvre and –Offset manoeuvre Only pass behind manoeuvres have been investigated as far as they are perceived by air traffic controllers as safer than pass in-front manoeuvres

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Conclusions Assessment, conducted using a set of modified radar encounters, indicates that: –Turning point manoeuvres perform better than offset manoeuvres but provide a greater maximum cross track deviation. –In addition, navigation errors (either from the ownship or from the target) significantly increase the percentage of unresolved conflicts by the airborne system. –Close links should exist between future airborne separation standards and navigation performance.

4 th Workshop, Amsterdam, 23 rd -25 th April 2007 Conclusions A static manoeuvre envelope may not be adequate to take advantage of lateral crossing manoeuvre opportunities. Depending on the initial position and velocity configuration of the conflicting aircraft, a static envelope may be over- or under-sized. Envelope issues could be overcome by means of a dynamic manoeuvre envelope or by broadcasting the intended lateral crossing manoeuvre.