Small UAS Well Clear Andrew Weinert 8 December 2016 EXCOM/SARP Multi-agency collaborative sponsorship FAA POC: Sabrina Saunders-Hodge, UAS Integration Office Research Division (AUS-300) DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited.
Legal Notices This material is based upon work supported by the Federal Aviation Administration under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Federal Aviation Administration. 2016 Massachusetts Institute of Technology. Delivered to the U.S. Government with Unlimited Rights, as defined in DFARS Part 252.227-7013 or 7014 (Feb 2014). Notwithstanding any copyright notice, U.S. Government rights in this work are defined by DFARS 252.227-7013 or DFARS 252.227-7014 as detailed above. Use of this work other than as specifically authorized by the U.S. Government may violate any copyrights that exist in this work. suas Well Clear - 2
Need for Quantitative Well Clear Definition for UAS Unmanned Aircraft Systems are required to maintain well clear and avoid collisions, in particular with manned aircraft FAR 91.111:...not operate so close to another aircraft as to create a collision hazard FAR 91.113: Vigilance shall be maintained so as to see and avoid other aircraft pilots shall alter course to pass well clear of other air traffic Quantitative well clear definition needed for the design and testing of separation systems for small UAS beyond line of sight operations This briefing outlines research towards a definition of well clear for small UAS for mid-term concepts of operations at low altitudes Beyond line of sight in general use airspace suas vs manned aircraft encounters Out of scope: suas vs suas encounters and airspaces such as airport terminals, over heliports or sporting events suas Well Clear - 3
Previous Effort for Large UAS Quantifying Safe Operations Detect and Avoid (DAA) Science and Research Panel (SARP) created in 2011 to coordinate DAA research Supports multi-agency UAS Executive Committee (ExCom) Large UAS well clear adopted by FAA Unmitigated risk threshold: P(NMAC WCV) = 5% SARP well clear working group formed to rapidly deliver recommendation to RTCA SC-228 Lack of well clear definition identified as highest priority research gap R&D: August 2013 August 2014 Multi-agency collaboration: FAA, DOD, NASA, MITRE, MIT LL, subject matter experts +450 ft 4000 ft Tau (time to 4000 ft) = 35 sec suas Well Clear - 4 NMAC = Near Mid-Air Collision WCV = Well Clear Violation
Well Clear as a Separation Standard for UAS* Separation standard, based on collision risk, informed by operational acceptability Future trajectories Relative state between aircraft Aircraft 2 Defined as the relative state where a desired risk threshold is achieved Unmitigated: regardless of ownship or intruder avoidance maneuvering Collision avoidance action likely not needed Aircraft 1 Collision Risk Acceptable Risk Threshold Approach: define risk threshold and map to other states (range, altitude, time, ) well clear Relative State Established Airspace Separation Standard Methodology Applied to Detect and Avoid suas Well Clear - 5 * Applies to unmanned aircraft only
Large UAS Well Clear Definition Process Overview Define forms and risk threshold Primary Roles: Define encounter models Tune candidate definitions Evaluate operational suitability MITRE, NM State U Process management MIT LL Monte Carlo simulations and tuning NASA Human in the loop (HITL) simulations USAF Stressing case analysis FAA Subject matter experts (SME) SARP review and approval at each step SME forum to down select candidates Make recommendation suas Well Clear - 6
Defining Well Clear for suas Community Objective: Develop a suas vs manned aircraft Well Clear definition based on risk and operational suitability Leverage lessons learned from large UAS well clear research Approach: Define desired unmitigated risk = P(NMAC Well Clear Violation) Explore different definition forms Existing (Large UAS) form: mod-tau*, horizontal and vertical thresholds Hockey Puck based on horizontal and vertical thresholds Tune parameters to risk threshold Based on M&S using suas CONOPS and dynamics in operational airspace Consider operational suitability for suas operators and airspace users suas Well Clear - 7 * Time to horizontal distance threshold NMAC Near mid-air collision (HMD 500 ft, VMD 100 ft)
Outline Well Clear Overview Modeling and Simulation M&S Components Representative suas Manned Aircraft Simulation Environment Results and Recommendation suas Well Clear - 8
Modeling & Simulation Components suas vs. Manned Aircraft Addressing challenges associated with limited suas flight data and limited manned flight data at altitudes below 1200 ft. AGL General Aviation (Part 91) Large UAS Weather suas Commercial Aviation (Part 121) Helicopter Air Ambulance Terrain & Vegetation Airspace Structure Birds Airspace Class suas Swarm People Buildings suas Well Clear - 9 Study Focus Potential Considerations
Risk Assessment Architecture: Monte Carlo Fast Time Simulations Collision Avoidance Safety System Tool (CASSAT) Raw radar data Tracking and fusion Feature extraction Encounter models Aircraft flight profiles and dynamics Fast-time simulation Surveillance models Collision Avoidance and Self-separation Algorithms Collisions per encounter Relative Risk analysis Previous Assessments Developed to certify TCAS version 7.1 SARP large UAS well clear definition Evaluation and tuning of multiple UAS algorithms Service Nodes Shared File System Network Storage Login Node Scheduler Monitoring System LL Grid Computing Environment LAN Switch Compute Nodes Cluster Switch Compute Nodes 274 Compute Cores 8768 Peak Performance 77.1 (TFLOPs) RAM (TB) 17.5 Central Storage (TB) 1,200 Distributed Storage (TB) 2,466 suas Well Clear - 10 Development Focus
Representative suas 55 lbs. while flying below 1200 ft AGL ID 1 2 3 4 MGTOW (lb)* 0-4.4 0-20 0-20 20-55 Mean Cruise Airspeed (kt) 25 20 30 60 Max Airspeed (kt) 40 30 60 100 Descend Rate (fpm) -300-500 -500-1000 Climb Rate (fpm) 500 700 700 1000 Notional suas Examples DJI Phantom 4 GoPro Karma Aeromapper 300 ScanEagle Trajectories Vertical Transit Horizontal Transit Creeping Line Spiral Sector suas Well Clear - 11 AGL Above Ground Level MGTOW Max Gross Take-Off Weight
Manned Aircraft Modeling Fixed-Wing and Helicopters Wide range of manned aircraft behavior simulated using two different probabilistic Bayesian network encounter models MIT LL Uncorrelated Fixed Wing Encounter Model Uncorrelated fixed-wing encounter model Represents low-altitude general aviation behavior Since 2008, has supported a wide-range of manned and UAS safety studies Helicopter air ambulance encounter model Represents at-risk low altitude helicopter operations Newly developed from anonymized FOQA records of Boston-area Medevac flights from 2015 2016 First helicopter focused statistical encounter model suas Well Clear - 12 FOQA Flight Operational Quality Assurance Data
Summary of Sensitivity Parameters suas 4 Representative Platforms 5 Trajectory Types Uncorrelated Manned Aircraft 1200 code Fixed-Wing Helicopter Air Ambulance Airspace Airspace Class (B,C,D,E,G) Region (CONUS, Offshore) Well Clear Forms Spatial (i.e. Vertical miss distance) Temporal (i.e. Tau) 6+ million encounters simulated to derive the unmitigated risk: Sensitivity of NMAC risk to various parameters analyzed. suas Well Clear - 13
Outline Well Clear Overview Modeling and Simulation Results and Recommendation Example encounter Sensitivity analysis Risk contours suas Well Clear - 14
Influence of Aircraft Speed Difference Encounter Example Encounter representative of DJI Phantom suas and Cessna 150 Manned aircraft flies 5X faster suas has minimal ability to influence outcome Y (ft) 5000 4000 3000 2000 1000 0 suas Manned CPA Time = 49 s Range = 930 ft Likely well clear violation -1000-2000 suas Manned Airspeed 15 kt 81 kt Distance traveled from start to CPA 1177 ft 6580 ft -3000-4000 -5000 0 X (ft) Start Time = 0 s Range = 5626 ft Start CPA Turn suas Well Clear - 15 CPA Closest point of approach
Sensitivity Analysis Example: Inclusion of Temporal Variables Spatial Only Spatial + Temporal 450 450 400 400 VMD (ft) 300 Example: 10% chance of an NMAC if HMD = 2000 ft & VMD = 250 ft VMD (ft) 300 200 200 100 1000 2000 3000 4000 HMD (ft) 100 1000 2000 3000 4000 HMD (ft) Adding temporal criteria to HMD and VMD filter has limited influence on P(NMAC Well Clear Violation) Attributed to suas relative slow airspeed Recommend suas well clear definition to only use (HMD, VMD) suas Well Clear - 16 HMD Horizontal miss distance (ft) VMD Vertical miss distance (ft) NMAC Near mid-air collision (HMD 500 ft, VMD 100 ft)
Sensitivity Analysis Example: suas Trajectories 450 Vertical Transit Horizontal Transit Pattern 450 450 400 400 400 VMD (ft) 300 VMD (ft) 300 VMD (ft) 300 200 200 200 100 5001000 2000 3000 4000 HMD (ft) 100 5001000 2000 3000 4000 HMD (ft) 100 5001000 2000 3000 4000 HMD (ft) NMAC risk has limited to no sensitivity to the suas trajectory suas in vertical transit has no horizontal ability to reduce risk At slow airspeeds, suas simply can t travel far during an encounter Unmitigated risk is not sensitive to a suas trajectory suas Well Clear - 17 HMD Horizontal miss distance (ft) VMD Vertical miss distance (ft) NMAC Near mid-air collision (HMD 500 ft, VMD 100 ft)
suas vs Manned Aircraft SARP s Well Clear Recommendation Hockey puck well clear definition using HMD and VMD 250 ft. VMD x 2000 ft. HMD ~ Half height and distance of large UAS well clear No temporal conditions Risk consistent across CONOPS, suas and manned aircraft dynamics models VMD (ft) Average risk contours over all models 450 400 350 300 250 200 P(NMAC WCV) (%) 150 Subject to additional validation Full technical paper in progress 100 500 1000 1500 2000 2500 3000 3500 4000 HMD (ft) SARP s Recommendation to FAA ExCom suas Well Clear - 18 HMD Horizontal miss distance (ft) VMD Vertical miss distance (ft) NMAC Near mid-air collision (HMD 500 ft, VMD 100 ft)
Summary Well clear definition for suas vs manned aircraft needed to extend operations to beyond line of sight Definition based on unmitigated risk and operational suitability Risk modeling required development of new low altitude encounter models Representative suas platforms and CONOPS New model for low altitude helicopter operations Risk determined to not be sensitive to assumptions Lack of sensitivity attributed to generally slow suas airspeeds Additional analyses recommended to evaluate niche cases such as consistently fast suas operations Additional community vetting of operational suitability expected SARP s recommended well clear definition: hockey puck centered on suas Horizontal 2,000 ft, Vertical 250 ft suas Well Clear - 19
Thank You Questions? Feedback? Andrew Weinert Associate Technical Staff Humanitarian Assistance and Disaster Relief Email: andrew.weinert@ll.mit.edu Phone: (781) 981-0986 Rodney Cole Assistant Group Leader Surveillance Systems Email: rodc@ll.mit.edu Phone: (781) 981-7423 suas Well Clear - 20