Advanced Speed Guidance for Merging and Sequencing Techniques

1. Advanced Speed Guidance for Merging and Sequencing Techniques Abstract This project develops improvements to speed guidance algorithms that will be used in an engineering testing environment. The concept of the original speed guidance algorithms was to compute a suitable speed for a plane to fly when following another aircraft based on the distance between the two aircraft. The estimated speed to fly would then be given to the pilot as a recommendation on a Cockpit Display of Traffic Information (CDTI). Initial testing of these algorithms showed that a speed to fly was calculated successfully, however, an incredible number speed recommendations were being produced. To prevent the pilot from being overwhelmed with speed recommendations, we created improvements to the algorithms with the specific goal of reducing the number of speed recommendations. Improvements to the algorithms were implemented by creating an improved speed calculation algorithm, quantizers, and rounding filters. The improved speed calculation algorithm searches for speed changes in the lead aircraft that are of great magnitude and, instead of giving many small consecutive recommendations, gives one large speed recommendation to the pilot for an extended period of time. The improved speed calculation algorithm was tested in a simulation that focused on human response patterns. After initial testing, the algorithm produced desirable results that at one point reduced what would have been nine speed commands into one command. The improved algorithm is an essential aspect to MITRE's Merging and Spacing simulations because it handles the final descent of an aircraft with unprecedented successes, allowing MITRE to take run experiments and simulations from takeoff to landing without interruptions. Improved Speed Calculation Algorithm One of the problems with current algorithms is that they do not handle large speed changes well. To a human, it is easy to identify when to make one large speed change instead of small consecutive speed changes that will result in an equivalent magnitude of change but this change is indistinguishable to a computer. During standard arrival procedures, an aircraft significantly slows down for landing purposes. Before the improved algorithm, simulations did not handle the final approach to an acceptable level so it could not be included in simulations and experiments because of the undesirable results. The improved speed calculation algorithm that we designed aims to fix this problem by searching for large speed changes in the lead aircraft. Previously, when there was a large change in the Indicated Air Speed (IAS) for the target, ownship attempted to follow the desired speed profile but instead of making one large speed change as the target aircraft did, ownship made many consecutive adjustments. The amount of adjustments that came out of the previous algorithms overwhelmed the pilot. The goal of the improved algorithm is to reduce the number of speeds recommendations that are sent to the pilot by giving the pilot one large speed command in place of multiple small commands. However, this must be done while maintaining the proper spacing between aircraft. The improved algorithm is necessary to avoid small consecutive adjustments such as these. By searching through the target Indicated Air Speed (IAS) history, the moment when the lead aircraft begin making a large IAS change can be detected and the corresponding magnitude of change can be estimated. This large speed change is then sent to the pilot as a recommendation for an extended period of time. Chris Sweeney Thomas Jefferson High School for Science and Technology MITRE Corporation Center for Advanced Aviations Systems Development Mentor: H. Peter Stassen Results and Conclusions We have consistently observed throughout our testing that the number of speed commands while running the improved algorithm can be reduced up to 50%. This feat was accomplished all the while maintaining acceptable spacing values, and is a significant improvement from the basic ``Merge Behind" and ``Remain Behind" applications. The largest role that the improved algorithm plays in the simulation is handling the final descent. Pilots typically make one large speed change to slow down aircraft during the final approach to the runway and under the basic spacing algorithms, many small, consecutive speed recommendations will be given to the pilot. The improved algorithm, on the other hand, gives one large speed recommendation. These algorithms were tested in a cockpit simulator in MITRE/CAASD's ATM lab. Using an interface called BigWig, the improved speed calculation algorithm was tested in a simulation that focused on human response patterns. BigWig creates an environment where trajectory data of aircraft in addition to environmental factors are considered. After initial testing, the algorithm produced desirable results that at one point reduced what would have been nine speed commands into one command. The improved algorithm is an essential aspect to MITRE’s Merging and Spacing simulations because it handles the final descent of an aircraft with unprecedented successes, allowing MITRE to take run experiments and simulations from takeoff to landing without interruptions. Procedure While research efforts to have not yielded a consensus on what algorithms should be included in the software, an overall procedure for the use of the algorithms has already been defined. Spacing algorithms aim to recommend speeds to fly so that proper spacing will be maintained between the ownship and target aircraft. These algorithms use trajectory data from the target aircraft to calculate the current spacing value, that is, a measurement of how far ownship is behind the target aircraft, and compares that to the desired spacing value. The desired spacing value is a spacing distance that is declared by the Air Traffic Controller that is monitoring the airspace. After comparing the current spacing value to the desired spacing value, a spacing error is calculated that indicates how far ownship is from the desired spacing value. In order to maintain the desired spacing value, the spacing error must be corrected. The speed to fly that will eliminate the spacing error, and thus obtain the required spacing value, is estimated and sent to the pilot as a recommendation. While this is the core of the procedure, there are other functions and algorithms which are used in unison with those listed above. These include filters, quantizers, and the improved algorithm.