Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work On the design of UAS horizontal separation maneuvers Enric Pastor Marc Pérez-Batlle Pablo Royo Raul Cuadrado Cristina Barrado Xavier Prats Universitat Politècnica de Catalunya (Barcelona-Tech) 2 nd SESAR Innovation Days, 2012
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Some concepts... Separation Assurance & Collision Avoidance Separation Assurance Aims at keeping minimum separation distance between aircraft and potential intruders. Typically responsibility of the ATC. Procedural Collision Avoidance Air Traffic Management Aims at preventing Self Separation imminent collision in case Cooperative Collision Avoidance of loss of separation. Non-cooperative Collision Avoidance
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Some concepts... Unmanned Aircraft Systems & Applications UAS UAS applications are increasing worldwide. Lack of regulation basis. Unconventional Flight Plans Flight plans more complex than point-to-point. UAS will loiter over certain areas of interest beyond the rigid nature of the airspace where they operate.
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Some concepts... UA vs. Airliner Performance comparison UAS may have poorer flight performance than commercial airliners Performance Parameter Unmanned Aircraft Manned Aircraft Cruise airspeed ↓↓↓ ↑↑↑ Rate of climb ↓↓↓ ↑↑↑ Cruise altitude ≈ ≈
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Some concepts... UA vs. Airliner Performance comparison UAS may have poorer flight performance than commercial airliners Performance Parameter Unmanned Aircraft Manned Aircraft Cruise airspeed ↓↓↓ ↑↑↑ Rate of climb ↓↓↓ ↑↑↑ Cruise altitude ≈ ≈
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Main goals Research Goals Motivation Conventional separation maneuvers may have a negative impact on the UAS mission. Significant performance differences between UA and airliners may lead separation maneuvers more complex. Objectives Model scenarios where a UA enters in conflict with a much faster airplane. Establish a taxonomy of UA separation maneuvers as a function of the conflict geometry that takes into account these dissimilarities. Apply latency and turn limitation aspects to the proposed separation maneuvers in order to validate them.
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Assumptions and Geometry definition Introduction 1 Some concepts... Main goals Geometry 2 Assumptions and Geometry definition Taxonomy definition Maneuvers 3 Catalog Turn limitation and latency 4 Latency Turn limitations Conclusions & Further Work 5 Conclusions & Further work Questions
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Assumptions and Geometry definition Assumptions and initial geometry definition Initial assumptions Only UAS is deviated and its heading change ∆ h is performed instantaneously. Aircraft are moving at constant speed. No latency in UAS communications are considered. Intruder position and velocity are know by the UAS via ADS-B. Symbol Definition A Airliner initial position v·t B UA initial position C A C' C Conflict Position (4-D) d β v Airliner velocity ( ∈ [ 300 , 600 ] kt ) d 0 u UA velocity ( ∈ [ 150 , 300 ] kt ) Δh Conflict angle β B u·t ∆ h Heading change ( ∈ [ − 90 , 90 ] ◦ ) Initial separation distance d 0 d Current separation distance
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Assumptions and Geometry definition ADS-B Requirements For ADS-B systems, the required acquisition range for a minimum alert time is 5 min. Therefore, acquisition range must remain constant regardless the conflict geometry. Coverage ADS-B antenna radiation pattern is not omnidirectional.
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Taxonomy definition Time to conflict and heading change analysis. Forward conflict ( β = 180 ◦ ) ∆ h for 170 kt ∆ h for 300 kt Separation Minima t c [minutes] t c [minutes] 2 5 10 2 5 10 3 NM 35 ◦ 15 ◦ 10 ◦ 20 ◦ 10 ◦ 5 ◦ 5 NM 55 ◦ 25 ◦ 15 ◦ 30 ◦ 15 ◦ 10 ◦ 10 NM N/A 45 ◦ 25 ◦ 65 ◦ 25 ◦ 15 ◦ Backward conflict ( β = 0 ◦ ) ∆ h for 170 kt ∆ h for 300 kt Separation Minima t c [minutes] t c [minutes] 2 5 10 2 5 10 10 o 3 NM 40 ◦ 15 ◦ 25 ◦ 10 ◦ 5 ◦ 25 o 15 o 10 o 5 NM N/A N/A 15 ◦ 10 NM N/A N/A 25 ◦ N/A 50 ◦ 15 ◦
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Taxonomy definition Time to conflict and heading change analysis. Other β . Minimum Separation for: Minimum Separation for: β = 45º, v = 170 kt, u = 500 kt β = 45º, v = 300 kt, u = 500 kt 40 40 t c = 10 min t c = 10 min 30 30 Separation [NM] Separation [NM] t c = 2 min 20 20 t c = 2 min 10 10 0 0 −100 −50 0 50 100 −100 −50 0 50 100 a) ∆ h [deg] b) ∆ h [deg] Minimum Separation for Minimum Separation for β = 90º, v = 170 kt, u = 500 kt β = 90º, v = 300 kt, u = 500 kt 40 40 t c = 10 min 30 t c = 10 min 30 Separation [NM] Separation [NM] 20 20 t c = 2 min t c = 2 min 10 10 0 0 −100 −50 0 50 100 −100 −50 0 50 100 a) ∆ h [deg] b) ∆ h [deg] M. Perez-Batlle, et al. "Evaluation of separation strategies for unmanned aerial systems" 5 th ICRAT. Berkeley, CA (USA): EUROCONTROL / FAA, May 2012.
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Catalog Catalog of separation maneuvers β β E ext β E ext d min Minimum Separation d min d min E ext E ext E d min E E Time for d min E E D β Δh Δh Δh Time for d min Time for d min E ext Forward & Oblique Lateral Backward
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Catalog Maneuver selection criterion The selection of the most effective maneuver depends on both UA speed and time to conflict t c . But...in which manner? and...When the UA could resume normal navigation? UAS Detection Boundary tc = 5min 270o 225o 315o 180o 0o 135o 45o 90o
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Catalog Maneuver selection results β threshold Feasible beta angle for Oblique Maneuver according to speed of the UAS and Time to Conflict Separation Target = 3 NM 20 t c = 2 min 15 Feasible Beta [deg] Maneuver 10 When oblique Unfeasible 5 Maneuver t c = 10 min separation maneuver 0 150 200 Speed [kt] 250 300 has to be replaced with Feasible beta angle for Oblique Maneuver back/forward ones? according to speed of the UAS and Time to Conflict Separation Target = 5 NM 35 30 t c = 2 min 25 Feasible Beta [deg] t c = 10 min Maneuver 20 15 10 Unfeasible 5 Maneuver 0 150 200 250 300 Speed [kt] Time to d min 5 14 When the UA could 12 4.5 v uas = 150 kt Time to d min [min] Time to d min [min] resume navigation on 10 v uas = 300 kt 4 oblique separation 8 maneuvers? v uas = 300 kt 3.5 6 v uas = 150 kt 3 4 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 80 90 a) ∆ h[º] b) ∆ h[º]
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Latency Latency issues Assumptions Conflict detection will be BLOS done on-board the UAS Relay ( t d , t ex ) . Conflict Detection Cooperative LOS/BLOS communications t d Aircraft ACAS ADS-B (different t net for each case). UA pilot on the decision loop Separation t ex Conflict ( t re ) . Command Detection t net Secondary Secondary Radar Non-negligible latency. Radar ABS-C ABS-C LOS Link Separation Command Proposed solution t d , t ex , t net are effectively Conflict Detection t re bounded. Ground Services Use of predicted positions of Enroute Surveillance Remote Piloting Centre Services both the UA and the intruder.
Introduction Geometry Maneuvers Turn limitation and latency Conclusions & Further Work Turn limitations Scheme & Results Decition & latency Roll time T A B β Decition & latency Roll time Minimum Turn A Separation Initiation d min t C Intruder S M Trajectory Reverse M Turn t Maneuver Minimum Turn initiated Separation Completed Target S As seen B Separation by the pilot Trajectory Minimum Separation Distance vs. β Target Separation: 5 NM α = 15º v uav = 300 kt v int = 500 kt 5 4 d min [NM] 3 2 t a = 0 seg 1 t a = 30 seg t a = 5 seg t a = 35 seg 0 90 95 100 105 110 115 120 125 130 135 140 β [deg]
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