TECHNOLOGY AREA(S): Air Platform, Electronics

ACQUISITION PROGRAM: PMA 266 Navy and Marine Corp Multi-Mission Tactical UAS

OBJECTIVE: Develop a software application capable of assessing the level of safety of various detect and avoid (DAA) technologies as they might be integrated on an unmanned aircraft (UA) operating in representative operational environments.

DESCRIPTION: In order to operate in civil and military airspace, Navy UA use DAA technologies and procedures to facilitate sharing airspace with other aircraft.  The capability to operate safely anywhere in the world must be demonstrated before the UA receives approval for operational missions.  Due to the potentially catastrophic consequences of error in the operation of the DAA systems, rigorous safety analyses are required to gain confidence in system effectiveness before deployment of the UA into airspace with manned aircraft.  Safety analysis should be conducted to determine whether the DAA sensor system’s performance (e.g., detection ranges, field of view, etc.) provide the UA operator timely and adequate information to maintain separation from intruding cooperative and non-cooperative aircraft by executing appropriate avoidance maneuvers with very low false track rates presented to the operator.

Develop a tool to assess the UA safety through the evaluation of the probability of a near mid-air collision (NMAC) and loss of separation given encounters under various conditions (e.g., intruder types, latencies) in operationally representative environmental conditions.  Example analyses include assessing the probability of maintaining separation for the set of practical worst-case encounters or for a large collection of realistic encounters representative of the operational airspaces.  The desired capability should utilize Government-provided encounter model data and UA flight characteristics to simulate UA and intruder motion through the closest point of approach (CPA).  Aircraft motion should be consistent with the UA 6 degree of freedom maneuver model utilizing Government-provided inputs.  The Government-identified DAA sensor and operational environment should be modeled with sufficient fidelity to accurately compute projected CPA and separation achieved by avoidance maneuvers.  The application should have the capability to represent various equipage configurations (to be identified by the Government) on the UA, including radar and potentially electro-optic and infrared sensors.  Ultimately, the application should provide time histories of the UA and the outcome of the encounter (e.g., whether or not a separation violation occurred) along with risk ratios as a basis in evidence for safety case-based certification. While approaches exist that address elements of the required analyses, no comprehensive and flexible approach exists that addresses the scope and detail needed.

PHASE I: Design, develop, and demonstrate feasibility of a comprehensive and detailed architectural description of the software application.  Identify all inputs (e.g., DAA sensor models, encounter characteristics, maneuver models, latencies) and outputs (e.g., risk ratios, encounter statistics).  Identify sources of necessary inputs such as airspace characterizations.  Describe and justify the level of fidelity of individual models.  Validate the approach using a variety of representative problems.  Prepare a complete application development plan, including prototype plans to be developed under Phase II.

PHASE II: Develop, demonstrate, and validate the prototype application for use within the Navy.  The validation cases and metrics will be provided by the Navy. Prepare a Phase III development and support plan to transition the technology to the Navy.

PHASE III DUAL USE APPLICATIONS: Perform any final testing and fully transition the technology to the Navy.  Extend the application to support DAA sensor certification by civil authorities.  Successful technology development should be equally applicable for the analysis of DAA sensors for certification in national airspaces governed by civil authorities.

REFERENCES:

1. Kochenderfer, M. J., Edwards, M. W., Espindle, L. P., Kuchar, J. K., & Griffith, J. D. “Airspace Encounter Models for Estimating Collision Risk. Journal of Guidance, Control, and Dynamics.” March 2010, 33(2), pp. 487-499.  https://www.researchgate.net/publication/245433739_Airspace_Encounter_Models_for_Estimating_Collision_Risk

2. Lutz, R., Frederick, P., Walsh, P., Wasson, K., & Fenlason, N.  “Integration of Unmanned Aircraft Systems into Complex Airspace Environments.” Johns Hopkins APL Technical Digest, Volume 33, Number 4 (2017). http://www.jhuapl.edu/techdigest/TD/td3304/33_04-Lutz.pdf

3. “Use of International Airspace by U.S. Military Aircraft and for Missile and Projectile Firings.” DoDI 4540.01, June 2, 2015.  https://fas.org/irp/doddir/dod/i4540_01.pdf

KEYWORDS: Unmanned Aircraft; Encounter Modeling; Sensor Modeling; Radar; Detect and Avoid; Safety Certification