Mark G. Ballin

A Flight Deck Decision Support Tool for Autonomous Airborne Operations

NASA is developing a flight deck decision support tool to support research into autonomous operations in a future distributed air/ground traffic management environment. This interactive real-time decision aid, referred to as the Autonomous Operations Planner (AOP), will enable the flight crew to plan autonomously in the presence of dense traffic and complex flight management constraints. In assisting the flight crew, the AOP accounts for traffic flow management and airspace constraints, schedule requirements, weather hazards, aircraft operational limits, and crew or airline flight-planning goals. This paper describes the AOP and presents an overview of functional and implementation design considerations required for its development. Required AOP functionality is described, its application in autonomous operations research is discussed, and a prototype software architecture for the AOP is presented.

Traffic Aware Strategic Aircrew Requests (TASAR)

Under Instrument Flight Rules, pilots are not permitted to make changes to their approved trajectory without first receiving permission from Air Traffic Control (ATC). Referred to as “user requests,” trajectory change requests from aircrews are often denied or deferred by controllers because they have awareness of traffic and airspace constraints not currently available to flight crews. With the introduction of Automatic Dependent Surveillance–Broadcast (ADS-B) and other information services, a rich traffic, weather, and airspace information environment is becoming available on the flight deck. Automation developed by NASA uses this information to aid flight crews in the identification and formulation of optimal conflict-free trajectory requests. The concept of Traffic Aware Strategic Aircrew Requests (TASAR) combines ADS-B and airborne automation to enable user-optimal in-flight trajectory replanning and to increase the likelihood of ATC approval for the resulting trajectory change request. TASAR may improve flight efficiency or other user-desired attributes of the flight while not impacting and potentially benefiting the air traffic controller. This paper describes the TASAR concept of operations, its enabling automation technology which is currently under development, and NASA’s plans for concept assessment and maturation.

NASA Langley and NLR Research of Distributed Air/Ground Traffic Management

Distributed Air/Ground Traffic Management (DAG-TM) is a concept of future air traffic operations that proposes to distribute information, decision-making authority, and responsibility among flight crews, the air traffic service provider, and aeronautical operational control organizations. This paper provides an overview and status of DAG-TM research at NASA Langley Research Center and the National Aerospace Laboratory of The Netherlands. Specific objectives of the research are to evaluate the technical and operational feasibility of the autonomous airborne component of DAG-TM, which is founded on the operational paradigm of free flight. The paper includes an overview of research approaches, the airborne technologies under development, and a summary of experimental investigations and findings to date. Although research is not yet complete, these findings indicate that free flight is feasible and will significantly enhance system capacity and safety. While free flight cannot alone resolve the complex issues faced by those modernizing the global airspace, it should be considered an essential part of a comprehensive air traffic management modernization activity.

A HIGH-PERFORMANCE SIMULATED ON-BOARD AVIONICS ARCHITECTURE TO SUPPORT TRAFFIC OPERATIONS RESEARCH

This paper describes the conceptual design and prototype development of a high-performance simulated avionics architecture that supports the exploration of new air traffic management concepts and technologies in a medium-fidelity computer workstation-based simulation. This simulated avionics architecture serves as the inter-process communications backbone of the Aircraft Simulation for Traffic Operations Research (ASTOR), which is the piloted simulation NASA Langley Research Center uses for examining the feasibility of new prototype airborne traffic conflict detection and resolution tools. The architecture chosen for ASTOR is that of an enhanced avionics data bus that achieves conceptual compatibility, rather than hardware compatibility, with existing avionics standards. It does this by making use of the data word and equipment channel definitions inherent in the ARINC 429 standard (and its accompanying ARINC 700series system characteristic documents), but also by not making use of any of the bit-level data encoding, hardware, or electrical signal characteristics of a physical ARINC 429 bus. This type of use of welldocumented communications standards for existing avionics components has aided the development of ASTOR by providing a common understanding of the conceptual data flows in the simulation, and also by supporting the evolutionary extension of current avionics capabilities to include new data sources and technologies.

Prototype flight management capabilities to explore temporal RNP concepts

Next generation air transportation system (NextGen) concepts of operation may require aircraft to fly planned trajectories in four dimensions - three spatial dimensions and time. A prototype 4D flight management capability is being developed by NASA to facilitate the development of these concepts. New trajectory generation functions extend todaypsilas flight management system (FMS) capabilities that meet a single required time of arrival (RTA) to trajectory solutions that comply with multiple RTA constraints. When a solution is not possible, a constraint management capability relaxes constraints to achieve a trajectory solution that meets the most important constraints as specified by candidate NextGen concepts. New flight guidance functions provide continuous guidance to the aircraftpsilas flight control system to enable it to fly specified 4D trajectories. Guidance options developed for research investigations include a moving time window with varying tolerances that are a function of proximity to imposed constraints, and guidance that recalculates the aircraftpsilas planned trajectory as a function of the estimation of current compliance. Compliance tolerances are related to required navigation performance (RNP) through the extension of existing RNP concepts for lateral containment. A conceptual temporal RNP implementation and prototype display symbology are proposed.

Autonomous aircraft operations using RTCA guidelines for airborne conflict management

A human-in-the-loop experiment was performed at the NASA Langley Research Center to study the feasibility of DAG-TM autonomous aircraft operations in highly constrained airspace. The airspace was constrained by a pair of special-use airspace (SUA) regions on either side of the pilots planned route. Traffic flow management (TFM) constraints were imposed as a required time of arrival and crossing altitude at an en route fix. Key guidelines from the RTCA airborne conflict management (ACM) concept were applied to autonomous aircraft operations for this experiment. These concepts included the RTCA ACM definitions of distinct conflict detection and collision avoidance zones, and the use of a graded system of conflict alerts for the flight crew. Three studies were conducted in the course of the experiment. The first study investigated the effect of hazard proximity upon pilot ability to meet constraints and solve conflict situations. The second study investigated pilot use of the airborne tools when faced with an unexpected loss of separation (LOS). The third study explored pilot interactions in an over-constrained conflict situation, with and without priority rules dictating who should move first. Detailed results from these studies were presented at the 5th USA/Europe Air Traffic management R&D Seminar (ATM2003). This overview paper focuses on the integration of the RTCA ACM concept into autonomous aircraft operations in highly constrained situations, and provides an overview of the results presented at the ATM2003 seminar. These results, together with previously reported studies, continue to support the feasibility of autonomous aircraft operations.

Airborne Conflict Resolution for Flow-Restricted Transition Airspace

An airborne conflict detection and resolution approach is presented for application to flights subject to metering constraints on descent. Conflict resolution (CR) is an extension of an existing genetic algorithm previously developed for the Autonomous Operations Planner (AOP). This approach provides for the avoidance of both traffic and area hazards simultaneously while meeting flight plan constraints.

A Cockpit-Based Application for Traffic Aware Trajectory Optimization

The Traffic Aware Planner (TAP) is a cockpit-based advisory tool designed to be hosted on a Class 2 Electronic Flight Bag and developed to enable the concept of Traffic Aware Strategic Aircrew Requests (TASAR). This near-term concept provides pilots with optimized route changes that reduce fuel burn or flight time, avoids interactions with known traffic, weather and restricted airspace, and may be used by the pilots to request a trajectory change from air traffic control. TAP’s internal architecture and algorithms are derived from the Autonomous Operations Planner, a flight-deck automation system developed by NASA to support research into aircraft self-separation. This paper reviews the architecture, functionality and operation of TAP.

Developing an Onboard Traffic-Aware Flight Optimization Capability for Near-Term Low-Cost Implementation

The concept of Traffic Aware Strategic Aircrew Requests (TASAR) combines Automatic Dependent Surveillance Broadcast (ADS-B) IN and airborne automation to enable user-optimal in-flight trajectory replanning and to increase the likelihood of Air Traffic Control (ATC) approval for the resulting trajectory change request. TASAR is designed as a near-term application to improve flight efficiency or other user-desired attributes of the flight while not impacting and potentially benefiting ATC. Previous work has indicated the potential for significant benefits for each TASAR-equipped aircraft. This paper will discuss the approach to minimizing TASAR’s cost for implementation and accelerating readiness for near-term implementation.

Evaluation of an Airborne Conflict Resolution Algorithm for Flow -Restricted Transition Airspace

†The Autonomous Operations Planner (AOP) is an airborne decision support tool under development by NASA. This paper evaluates the performance of the conflict detection and resolution (CD&R) function within AOP in a descending transition environment. One of the critical aspects of this environment is the ability of the flight to meet separation requirements and traffic flow management (TFM) constraints such as required times of arrival (RTA). We present results of a Monte Carlo experiment, applied to the above CD&R algorithm and subject to real -wo rld disturbances, illustrating that the system is capable of delivering separation while meeting RTA and altitude constraints within a certain tolerance. This paper provides a quantitative assessment of the performance of the conflict detection, in light of the differing information quality between own -ship, autonomous traffic and managed traffic. System Operating Characteristic (SOC) curves are presented illustrating the behavior of the conflict detection under various control strategies for meeting alti tude and arrival time constraints. The results indicate that recalculation of descent profiles to meet altitude and time constraints yields improvements in performance over current vertical navigation approaches. The impact of the number of trajectory ch ange points (TCP) broadcast by traffic aircraft on the performance of conflict detection is also evaluated. Significant degradation of performance is obtained as the number of TCPs is reduced. Different resolution strategies (e.g., lateral and vertical) are compared to determine which strategy is most effective in an environment subject to disturbances.