Advanced Speed Guidance for Merging and Sequencing Techniques Chris Sweeney,

MITRE Corporation Center for Advanced Aviation System Development Mclean, VA

Introduction Research experts have been working to create software that can be put aboard aircraft to help Air Traffic Controllers manage merging streams of traffic The goal is to keep the aircraft properly spaced as they arrive at the airport Current algorithms estimate a speed to fly so that the aircraft will be properly spaced Speed to fly is sent to the pilot as a recommendation Goal of this project is to create a product for UPS to use UPS has many airplanes coming into airports at night so this software will help Air Traffic Controller manage the large amounts of aircraft

Background New technology called ADS-B enables aircraft to send trajectory data directly to another aircraft With this advancement, aircraft can send data that is necessary to use this data to calculate a recommended speed to fly ADS-B communicates very frequently, so the recommended speed to fly can be recalculated often to improve accuracy

Current Algorithms Uses time based spacing, how many seconds behind lead aircraft Time based spacing naturally compresses and expands as speed changes Desired spacing value is the ideal spacing (normally 120 seconds) Spacing error is the difference between current spacing value and desired spacing value

Current Algorithms

Current Algorithm A more accurate method is to save trajectory data of the lead aircraft Look at lead aircraft’s position at t-desired spacing seconds ago This position is where you want to be Spacing error is the difference between current position and that position

Current Algorithms Goal of the algorithm is to fix the spacing error Recommended speed to fly is the estimated speed that will correct the spacing error Oscillations as a result of small speed or altitude changes in the target aircraft are reflected in the recommended speed to fly

Problems Current algorithms present too many speed commands Overwhelms and distracts the pilot Can become unstable Constantly changing speed recommendations are obnoxious to a pilot Surveys have shown that pilots are more likely to ignore the recommendations if they are constantly changing or oscillating frequently

My Project Reduce the number of speed commands to a manageable number Do this while maintaining proper spacing Make an Improved Speed Calculation algorithm Create filters and quantizers to reduce the number of commands

Improved Speed Calculation When the lead aircraft makes a large speed change, the normal algorithm takes many small consecutive steps (blue line) This can be reduced to one large command (green line)

Improved Speed Calculation Start at t-desired spacing Calculate the acceleration at that point If the acceleration is above a threshold, then the change is large enough that we will run the improved algorithm Progress to next data point Run the algorithm while the acceleration at the current data point is above the threshold

Improved Speed Calculation When the algorithm stops –Calculate duration: difference between time at data point where it stops and t-desired spacing –Calculate magnitude of change: difference speed at data point where it stops and speed at t-desired spacing Recommended speed to fly = current speed + magnitude of change Recommended speed to fly stays displayed for “duration” seconds

Improved Speed Calculation

Experiments MITRE has a flight simulator in the Air Traffic Management Lab We recorded a flight from start to finish Ran a simulation where that flight was used as the lead aircraft and we were the trail aircraft Simulation featured a focus on human factors such as reaction time 45 minute real-time simulations run times Fast time simulations run 5-10 times

Experiments Above: The cockpit of MITRE CAASD’s flight simulator in the ATM lab Left: Speed Recommendations are displayed on the left side of the CDTI

Results We consistently observed a reduction in speed recommendations of 50% During major speed changes, what would normally be 9-12 recommendations were reduced to 1 large recommendation Even when speed changes were not large enough for the improved algorithm to run, the filters and quanizers significantly reduced the number of recommendations

Implications During standard arrival procedures, aircraft significantly reduce speeds Prior to the Improved Speed Algorithm, simulations could not include arrivals because the results were extremely unpleasant This breakthrough allows MITRE to run a broader range of tests from departure to arrival without interruption This is a major step to preparing the product for field testing

Reflections Extremely valuable to see how computer science and engineering can be applied to a real life product Advice: read carefully, try to think about things in a larger scope while maintaining a detailed understanding Work Environment: There were several TJ grads at MITRE so it was very easy to relate to people. No real adjustment was necessary other than maintaining acting professional Remember, you’re representing yourself, the school, and your demographic!

Acknowledgements H. Peter Stassen Matthew Pollack Kelley Connolly Urmila Hiremath Mr. Latimer Mr. Pearce

Works Cited EUROCONTROL, ”CoSpace 2005-ASAS Sequencing and Merging: Flight Deck User Requirements Version 2.1”, EUROCONTROL, E. Hoffmann, N. Pene, K. Zeghal, ”ASAS Spacing User Requirement Document”, EEC document version 2.0 I. Grimaud, E. Hoffman, L. Rognin, K. Zeghal, ”EACAC 2000 Real- Time experiments: Pilots perspectives”, EEC Report version 3.0 EUROCONTROL/FAA, ”Principles of Operations for the Use of Airborne Separation Assurance Systems”, EUROCONTROL/FAA Cooperative R&D Edition 7.1, 2001 J. Hammer, ”Preliminary analysis of an approach spacing application”, FAA/Eurocontrol R&D committee, Action plan 1, ASAS Technical Interchange Meeting, 2000