Arash Yousefi

Dynamic Airspace Configuration Management based on Computational Geometry Techniques

New techniques for dynamic airspace configuration in the National Airspace System based on computational geometry techniques are investigated. The current airspace is subdivided into Air Route Traffic Control Centers and sectors of airspace that remain statically defined. New methods of designing airspace regions that are balanced in terms of workload per unit area over a given planning time period are presented. Configuring the airspace dynamically provides a means to change sector designs from one day to the next or within the course of a single day, to better balance controller workload. A recursive, top-down partitioning algorithm is used to subdivide a given 2D polygonal region R of airspace (e.g., a center) into sector regions. Three types of local partitioning are investigated: straight-line cuts, pie-cuts, and wheel-cuts. During each subdivision, the local partitioning balances workload among the resulting subregions, while other shape parameters, such as aspect ratio, are kept within acceptable bounds. Experiments show promising results for balancing workload. Airspace designs were shown to controllers, and their feedback regarding design considerations were summarized for use in improving our modeling approach.

Nextgen flow corridors initial design, procedures, and display functionalities

We present initial design of NextGen flow corridors and provide examples of corridor building blocks. We discuss important factors to consider when designing the shape and dimensions of corridor building blocks. In addition, we use existing procedures for Area Navigation (RNAV) routes as a basis for developing operational procedures to implement flow corridor operations. Sample procedures are presented to cover the role of pilots, controllers, or other Air Navigation Service Provider (ANSP), as well as the capabilities and information each party has to receive to perform the described procedures. Finally, required displayed functions for pilot and controller are discussed and illustrated in the context of selected scenarios. The work we present in this article is intended to be used for design and development of Human-In-The-Loop studies for corridors proof of concept.

Trigger Metrics for Dynamic Airspace Configuration

t W , = traffic load change from time period tx to ty x t ij c , = number of aircraft transferred from cell i to its adjacent cell j during each time period tx N(i) = set of adjacent cells to cell i si = supply of node i di = demand of node i xij = amount of commodity transferred from node i to node j h = index for dummy node ph,i = artificial cost of transferring one unit of commodity to/from a dummy node to/from other demand/supply nodes x t i A , = set of cell indexes such that those cells together with cell i construct a sector during time period tx x t M = number of sectors during time period tx

Algorithmic Traffic Abstraction and its Application to NextGen Generic Airspace

We develop traffic abstraction algorithms that, given a set of 4D Trajectories (4DTs), extract the traffic structure in terms of standard flows and critical points (conflict and merge points). We demonstrate the application of our techniques to enable the NextGen generic airspace concept. We also analyze historical demand data to evaluate the level of abstraction underlying the en-route traffic within high-altitude sectors. Finally, we compare the structure of historical traffic to user preferred, wind optimal futuristic trajectories.

Integrated arrival and departure weather avoidance routing within extended terminal airspace

Analysis of historical trajectories showed that when weather is impacting terminal operations, it is common for flights to deviate from published routes, even to the extent of using departure airspace for arrivals. This demonstrates that more flexible routing is needed in terminal airspace, especially when there are weather constraints. In this paper, we present an algorithm for the integrated design of dynamic arrival and departure weather avoidance routing within extended terminal airspace. This algorithm can serve as a strategic planning tool to aid air traffic controllers in managing terminal operations during weather events. Due to safety and efficiency considerations, arrival route structures are first designed and then modeled as constraints when designing the departure routes. The algorithm combines trajectory optimization with heuristics and takes into account human factors constraints, such as distance between merge points and number of merging flows per merge point. We demonstrate through fast-time simulation that dynamic weather avoidance routing can improve terminal operation efficiencies.

Weather avoidance optimal routing for extended terminal airspace in support of Dynamic Airspace Configuration

This paper describes an algorithmic approach for designing dynamic route structures for extended terminal airspace in the presence of convective weather. The algorithm combines trajectory optimization with heuristics to design efficient weather avoidance dynamic route structures. Optimal routing is performed for as far as 150 nautical miles from major airports. In support of Dynamic Airspace Configuration, factors such as distance between merge points, number of merging flows per merge point, and robustness of routes with respect to uncertainties in weather forecasts are explicitly considered. We present analysis of historical terminal operations that was conducted to identify suitable scenarios and also to gain insights and guidance for the design of dynamic route structure. We also present the algorithm details and experimental results.

An Ensemble-Based Approach for Representing Weather Uncertainty in Air Traffic Management

We developed a model to generate synthetic weather ensembles by using real weather data and jointly sampling from the distribution provided for precipitation level in the cells of a weather map. In our sampling approach, we account for both temporal and spatial correlations between weather cells by constructing an appropriate covariance matrix. As the result, the consistency in weather maps are preserved in both time and space in generated weather ensembles. This model can be used in air traffic management problems to generate a set of realistic weather ensembles representing weather uncertainty in both tactical and strategic time frames. The results from application of this model to integrated dynamic airspace configuration and traffic flow management analysis is presented in this paper.

Analysis of performance of Q routes for establishing future design criteria

Q routes are en route airway routes, between FL180 and FL450, which can be flown by RNAV equipped aircraft capable of conforming to navigation specified by RNAV 2. Q routes, in use since late 2003, provide more direct routing compared to conventional routes, and are intended to reduce flight distance and travel time.

Effectiveness of Dynamic Airspace Configuration to Manage Airspace Capacity in Response to Highly Dynamic Changes in Traffic Demand and Weather Events

We present experimental results to gain insight into how dynamic airspace capacity management can alleviate or support Traffic Flow Management (TFM) initiatives. Through analysis of historical flight and weather data, we explore mechanisms by which Dynamic Airspace Configuration (DAC) and TFM models can interact and exchange information to provide airspace capacity where and when it is most needed by users.

Robust airspace design methods for uncertain traffic and weather

We present a robust optimization framework for performing Dynamic Airspace Configuration (DAC) integrated with Traffic Flow Management (TFM) under weather uncertainties. We extend the existing cell-based Mixed Integer Programming (MIP) model along with the GeoSect sectorization method to incorporate probabilistic weather predictions in airspace sectorization. An ensemble generation method is devised to take a probabilistic weather forecast and generate weather ensembles. The weather ensembles are then fed into a TFM agent developed to compute weather avoidance 4D trajectories (4DT) and to create traffic ensembles. Robust sectorization algorithms use traffic and weather ensembles to produce robust sector boundaries that are feasible and close to optimal for each of the traffic ensembles. Several experiments are presented for testing the degree of robustness of generated sectors across different traffic ensembles.