Army Ground-Based Sense and Avoid for Unmanned Aircraft

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1 Army Ground-Based Sense and Avoid for Unmanned Aircraft Dr. Rodney E. Cole 27 October, 2015 This work is sponsored by the Army under Air Force Contract #FA C Opinions, interpretations, recommendations and conclusions are those of the author and are not necessarily endorsed by the United States Government.

2 Army GBSAA Program Overview High DoD need to fly unmanned aircraft in the NAS for training and launch of international flights Shadow to Global Hawk sized UAS Many needs can be met with a local sense and avoid solution Army developing DoD-wide general purpose Ground-Based Sense and Avoid system Initial capability to be deployed in FY16, additional capability roll-outs planned First operational deployment to FT Hood FY16 Four additional Army deployments currently funded Two Air Force sites planned Army Ground-Based Sense and Avoid for Unmanned Aircraft - 2

3 Army Current Concept of Operations Requires Certificate of Authorization Transit from Class D to restricted airspace Multiple ground observers Daylight, visual conditions Restricted Airspace Ground Observer Ground Observer Ground Observer Army Ground-Based Sense and Avoid for Unmanned Aircraft - 3

4 Army Desired Concept of Operations Blocks 0 and Block 1 Requires Certificate of Authorization Enables flight in Class C/D/E/G airspace Single observer * (GBO) Ability to fly at night System also capable of enabling MOA operations * Air force will provide information direct to the pilot FAA Radar Restricted Airspace LSTAR Radar GBO Block 0: Traffic and alert display Block 1: Adds automated maneuver guidance Army Ground-Based Sense and Avoid for Unmanned Aircraft - 4

5 Army Desired Concept of Operations Block 2 Requires Certificate of Authorization Enables flight in Class C/D/E/G airspace Information given to aircraft operator Ability to fly at night System also capable of enabling MOA operations FAA Radar Restricted Airspace Block 2+: Information straight to operator LSTAR Radar Block 2: adds additional features, TBD Army Ground-Based Sense and Avoid for Unmanned Aircraft - 5

6 Army Ground Based Sense and Avoid (GBSAA) Architecture GBSAA Elements GBSAA (1 per site) LSTAR GBSAA operations room UA Element GBSAA Processor Unit ASR Up to 6 radars Fiber/comm Voice comm Command Link GCS Shelter (Up to 6) ATC Common air picture for a site Individual threat logic and display units for each UA Army Ground-Based Sense and Avoid for Unmanned Aircraft - 6

7 Approval Process Army Aviation Engineering Directorate (AED) providing airworthiness approval Supported by the Army Software Engineering Directorate (SED) DO-178C software process DO-254 hardware Process coordinated with and agreed to by the FAA Safety Case Fault tree/hazard analysis Fast-time modeling and simulation of threat logic Human-in-the-loop laboratory testing Field testing of production system Covered in this briefing Note: final system and subsystem safety thresholds are being reviewed, thresholds used in this briefing are unofficial and conservative. Army Ground-Based Sense and Avoid for Unmanned Aircraft - 7

8 Outline Program Overview Threat Logic Assessment Operational Evaluation HITL Summary Army Ground-Based Sense and Avoid for Unmanned Aircraft - 8

9 Threat Logic Functional Blocks Input Processing Proximate Track Assessment Threat Track Assessment TAAZ Filter Sort and Merge Output Processing Proximate Track Assessment Yellow alert: Caution, operator discretion Intruder within: 7500 ft vertically, 4 nmi horizontally, 135 sec to closest approach Terminal Area Alert Zone Filter Enables operator discretion in terminal area Sort and Merge alerts by priority Threat Track Assessment Similar to ACAS X Red alert: Must address Goal: maintain 1000 ft x 1 nmi separation Army Ground-Based Sense and Avoid for Unmanned Aircraft - 9

10 GBSAA Threat Logic Development Key requirements differences with ACAS Xa Ground-Based Sense and Avoid Unmanned Aircraft Operational Volume Threat Aircraft Different track error characteristics Must perform conflict avoidance at greater range UAS have different performance limits than manned aircraft Logic Differences UAS Ground Station Operating Base Ground-Based Radar Array Action space in horizontal rather than vertical Safety goal includes self-separation as well as avoiding collision Dynamics model appropriate for generic DoD UAS Army Ground-Based Sense and Avoid for Unmanned Aircraft - 10 MS-54062C

11 Logic Robustness to System Uncertainties Threat Logic Dynamic Uncertainty State Uncertainty Logic explicitly models uncertainty in: Intruder future maneuvers Aircraft current track position Aircraft current track velocity UAS operator response latency Algorithm robustness to uncertainties must be demonstrated Explicitly modeled uncertainty Unmodeled uncertainty Wind Different UAS turn performance Assessed by fast-time simulation of red threat alerts and Block 1 maneuver guidance Preliminary 1 risk ratio 2 safety target Threat alert allocation: ) Used for OE test, official safety targets being reviewed 2) Risk ratio = #near mid-air collision with system/#near mid-air collisions without system Army Ground-Based Sense and Avoid for Unmanned Aircraft - 11

12 Fast-Time Safety Modeling and Simulation Framework Raw radar data Tracking and fusion Feature extraction Encounter models Aircraft flight profiles and dynamics Fast-time simulation Surveillance model Collision avoidance system models (algorithms) Collisions per encounter Relative risk analysis Realistic Fast-Time Simulation: millions of encounters Originally developed for safety assessments of TCAS 7.0 Adapted for uncorrelated intruders, UAS and various sensors and algorithms In this briefing applied to only red alerts, assumes pilot ignores all yellow alerts Army Ground-Based Sense and Avoid for Unmanned Aircraft - 12 MS-57023B

13 Vertical Error ft (std dev) System Robustness Sensitivity to Track Location Error Horizontal Error - ft (std dev) Risk ratio remains below target of 0.10 Estimates of track error explicitly included in logic Note: includes uncertainty in future intruder maneuvers Army Ground-Based Sense and Avoid for Unmanned Aircraft - 13

14 System Robustness Sensitivity to Achieved Turn Rate RR = 0.10 Assumes track error std 500 ft vertical and horizontal Pilot delay of 8 seconds Includes uncertainty in future intruder maneuvers Risk ratio remains below 0.10 over a large range of turn rates System assumes 3 deg/sec turn rate variance not included in logic System degrades gracefully with reduced UAS turn performance Logic can be tuned for different assumed turn rate if desired Army Ground-Based Sense and Avoid for Unmanned Aircraft - 14

15 System Robustness Sensitivity to Wind Assumes track error std 500 ft vertical and horizontal Pilot delay of 8 seconds Includes uncertainty in future intruder maneuvers Risk ratio remains below 0.10 over a large range of wind speeds Winds are not included in logic Winds help as often as hurt Assumes airspeed at least 20kts > wind speed Army Ground-Based Sense and Avoid for Unmanned Aircraft - 15

16 Outline Program Overview Threat Logic Assessment Operational Evaluation HITL Summary Army Ground-Based Sense and Avoid for Unmanned Aircraft - 16

17 GBSAA OE Evaluation Overview Block 0 Test Goals Verify safety, usability, usefulness from human perspective Collect data to support airworthiness approval Verify safety in intended airspace Test of: Assess algorithm Traffic Display Alert Display Yellow Proximate alerts and Red Threat alerts No maneuver guidance Alert Display Traffic Display GBO Army Ground-Based Sense and Avoid for Unmanned Aircraft - 17

18 GBSAA OE Evaluation Set-Up Scenarios Use Case: Synthetic flights representative of Ft Hood missions Envelope Case: Very challenging multi-intruder flights Risk Ratio: Challenging multiintruder flights GBSAA Operators 5 Air traffic controllers and 3 pilots Each ran each scenario Alerts, Maneuvers, Tracks, Separation distances captured User feedback via surveys Used production code and hardware Fusion, Assess, Displays Pre-certification HITL run at MIT LL March 29 April 10, 2015 Army Ground-Based Sense and Avoid for Unmanned Aircraft - 18

19 GBSAA OE Displays and Tools Traffic Display Alert Display Operator Input Widget UAS Operator Station Army Ground-Based Sense and Avoid for Unmanned Aircraft - 19 Source: SRC CDR presentation, August 2014 (GBSAA displays only)

20 Vertical separation (ft) Vertical separation (ft) Closest Point of Approach 2000 Without GBSAA 2000 With Block 0 GBSAA Separation Goal NMAC Horizontal separation (nmi) Horizontal separation (nmi) Each scenario flown 8 times In Without GBSAA case each repeat flight gives the same result Repeated points are spread into light blue points to normalize plot density Only encounters with CPA within 2000 ft vertical and 2 nmi horizontal shown Demonstrates GBO and aircraft operator ability to maintain safe separation Army Ground-Based Sense and Avoid for Unmanned Aircraft - 20

21 Average Workload Average SA Average Workload Average SA Workload and Situation Awareness 5 Average Workload by CPA 5 Average Situational Awareness by CPA 4 3 envelope use case 4 3 envelope use case 2 risk ratio 2 risk ratio CPA bins (NM) CPA bins (NM) 5 Workload by Intruder Count 5 Situation Awareness by Intruder Count Intruder Count envelope use case risk ratio Intruder Count envelope use case risk ratio Army Ground-Based Sense and Avoid for Unmanned Aircraft - 21

22 OE Results Summary High level safety results Zero NMACS Self-separation violations reduced by 98.8% Operator first action by alert type 28% of maneuvers made with no alert 46% of maneuvers made during proximate alerts (yellow only) 26% of maneuvers made on threat alert (red alert) Operators expressed support and approval of the displays System was very easy to use for identifying threats and performing GBO tasks Army Ground-Based Sense and Avoid for Unmanned Aircraft - 22

23 Outline System Overview Threat Logic Assessment Operational Evaluation HITL Summary Army Ground-Based Sense and Avoid for Unmanned Aircraft - 23

24 Summary Army GBSAA is being developed to rigorous DO-178C standards System has undergone significant testing Initial flight testing at Dugway Proving Grounds in 2012 Modeling and Simulation throughout development Human-in-the-Loop at Lincoln 2015 Production system flight testing at Dugway Proving Grounds UT, Ft Hood TX, winter 2015/2016 Operations planned to begin in FY16 5 Army sites and 2 AF sites currently planned Army Ground-Based Sense and Avoid for Unmanned Aircraft - 24