En Route Traffc Optmzaton to Reduce Envronmental Impact John-Paul Clarke Assocate Professor of Aerospace Engneerng Drector of the Ar Transportaton Laboratory Georga Insttute of Technology
Outlne 1. Introducton 2. Optmzng a Corrdor of Traffc 3. Optmzng Intersecton Traffc Flows 4. Conclusons
Introducton Delays Currently Impact Operatons $5 Bllon Impact [Boeng 2001] Ar Traffc Projected to Grow Sgnfcantly Up to three tmes more traffc 250% Increase n Delay Hours Arborne Delays Comprse 24% of all Delay Tme [FAA 2000] Potental benefts of decson-adng tool to optmally assgn flghts to avalable flght levels wthn a corrdor and route traffc n a horzontal plane Arcraft performance s dependent on alttude and velocty Correspondng emssons and fuel burn savngs Resource allocaton problem
Optmzng a Corrdor of Traffc Northeastern Unted States s a good example of a domestc corrdor that would beneft from mproved alttude and speed assgnments Severely congested Restrcted arspace Geographcal algnment Urban densty Oceanc tracks are corrdors that could also beneft from mproved alttude assgnment as arcraft sometmes get stuck behnd slower arcraft Changes n lateral path restrcted
Arcraft Cruse Performance 101 Fuel burn curves have dfferent operatng ponts Mnmum delay (.e. max. cruse speed) Mnmum fuel burn rate Mnmum total fuel burn T R T V mn V endurance V range V
Northeastern US n Focus Arports wth 20,000+ Hours of Annual Delay Arspace Restrctons Phladelpha Baltmore Approx. Corrdor Bounds Washngton Restrcted Arspace Approx. Coast Lne
Analyss of Northeastern US BADA Data ETMS Data Arcraft Models Performance Modelng Flght Envelopes Traffc Modelng Scenaro Modelng NAS Jetways Jetway Dstrbutons Set of Scenaros Decson Model Smulaton Results
Scenaros Baselne (Sngle Jetway) Provdes estmate of optmzaton benefts Reduced Vertcal Separaton Mnmum (RVSM) Provdes more capacty overall
Optmzaton Algorthm max N subject to : or mn Tv = x x, N Ta = v v, N 0 0 k k v C(1 z ) + v, N, k M k k v C(1 z ) + v, N, k M a a = 2 fps, N a a = 2 fps, N k z = 1, N y + y = 1, N, j N j y = 0, N N max mn k M x j j mn max j x f k k x C(3 z z y ) + s, N, j N, k M j j f C(1 z ) + a v + b, N k k k 1 1 f C(1 z ) + a v + b, N k k k 2 12 f C(1 z ) + a v + b, N k k k 3 3 f C(1 z ) + a v + b, N k k k 4 4 Objectve Knematcs Performance Sequencng Separaton Fuel Burn
Delay & Fuel Burn Benefts Baselne Up to 8.5 mnutes delay savngs per arcraft Up to 160 gallons of fuel per arcraft RVSM 45% addtonal delay reducton No addtonal fuel burn reducton
Optmzng Intersecton Traffc Flows Ensure safety Satsfy transfer constrants between sectors Avod obstacles Mnmze devaton Reduce fuel costs
Changng Trajectores to Avod Conflcts and Mnmze Cost (e.g. Fuel Burn) Method 1: Change Arspeed of each Arcraft Method 2: Change Headng of each Arcraft Method 3: Change both Arspeed and Headng of each Arcraft
Optmzaton Formulaton Cost Functon Evaluaton Crtera Constrants Equaltes: Defne varables Inequaltes: Allowable regons
Cost Functon Fuel and headng cost for each plane Max fuel and headng cost for all planes Decson varables are
Safety Constrants Safety regons defned usng relatve velocty vector Case 2 Case 1 Case 3 and are gven from ntal condtons
Example: Baselne (No Changes) - Intal Trajectory - Desred Trajectory
Example: Arspeed and Headng Changes - Intal Trajectory - Desred Trajectory - Optmal Trajectory QuckTme and a H.264 decompressor are needed to see ths pcture.
Cleveland Center Study Cleveland ARTCC subject of case-study Center s defned by a collecton of lattude,longtude boundary fxes Sector s non-convex so t has been parttoned nto a complmentary and comprehensve set of convex regons Currently developng smulaton to Evaluate algorthm performance Study farness mplcatons Wll develop enhanced algorthm that consders farness whle optmzng traffc flow
Conclusons Prelmnary results suggest that there are sgnfcant emssons and fuel burn savngs to optmally Assgn arcraft to amongst avalable alttudes wth a traffc flow Reroute traffc flows to prevent conflcts (wth other arcraft, weather, terran) Algorthm framework provdes means for reroutng arcraft around other arcraft, weather, and terran at mnmum cost n terms of emssons and fuel burn Potental to reroute around super saturated ar masses to avod contral formaton Further research needed to take deas to a workng prototype