1 Target Geolocation from a Small Unmanned Aircraft System Richard Madison & Paul DeBitetto The Charles Stark Draper Laboratory 555 Technology Square Cambridge, MA 02139 617-258-4305 {RMadison, PDeBitetto}@draper.com A. Rocco Olean Natick Soldier RDEC Kansas Street Natick, MA 01760 508-233-6466 Adam.Rocco.Olean@us.army.mil Mac Peebles AeroVironment, Inc. 900 Enchanted Way Simi Valley, CA 93065 805-581-2198 peebles@avinc.com Abstract—Draper Laboratory and AeroVironment, Inc. of Monrovia, CA are implementing a system to demonstrate target geolocation from a Raven-B Unmanned Aircraft System (UAS) as part of the U.S. Army Natick Soldier Research, Development & Engineering Center’s Small UAS (SUAS) Advanced Concept Technology Demonstration (ACTD). The system is based on feature tracking, line-of- sight calculation, and Kalman filtering from Draper’s autonomous vision-aided navigation code base. The system reads imagery and telemetry transmitted by the UAS and includes a user interface for specifying targets. Tests on a snapshot of on-going work indicate horizontal targeting accuracy of approximately 10m, compared with 20-60m for the current Raven-B targeting software operating on the same flight video/telemetry streams. This accuracy likely will be improved through further mitigation of identified error sources. This paper presents our targeting architecture, the results of tests on simulator and flight data, an analysis of remaining error, and suggestions for reducing that error. 12 TABLE OF CONTENTS 1. INTRODUCTION...................................................... 1 2. TARGETING METHODS.......................................... 2 3. DVAN .................................................................... 5 4. TARGETING ARCHITECTURE ................................ 5 5. SIMULATION .......................................................... 8 6. FLIGHT TEST 1 .................................................... 10 7. FLIGHT TEST 2 .................................................... 13 8. ERROR SOURCES AND MITIGATION ................... 14 9. CONCLUSION ....................................................... 17 ACKNOWLEDGEMENT ............................................. 18 REFERENCES ........................................................... 19 BIOGRAPHY ............................................................. 19 1. INTRODUCTION The Small Unmanned Aircraft Systems (SUAS) military user community has indicated a desire for improved reconnaissance and surveillance capabilities for tactical SUAS, defined as rucksack portable systems whose air vehicle component (UAV) has less than 15 pounds gross 1 1-4244-1488-1/08/$25.00 ©2008 IEEE 2 IEEEAC paper #1244, Version 7, Updated November 23, 2007 vehicle weight. The SUAS Advanced Concept Technology Demonstration (ACTD) at Natick Soldier Research, Development & Engineering Center (NSRDEC) has been tasked to develop these capabilities. The ACTD is a government R&D program focused on investing in high technology readiness level (TRL 6-8) technologies, conducting a structured assessment process, and transitioning those technologies that exhibit military utility. Oversight responsibility is the purview of the Deputy Under Secretary of Defense (DUSD) for Advanced Systems & Concepts (AS&C). One area of technology development under investigation by the ACTD is the ability to detect, geolocate, and identify/ classify targets of interest. An important piece of this is targeting, which can be defined as the combination of two related processes: the generation of a coordinate in military grid reference system (MGRS); and the transmission of this coordinate through the appropriate communications systems and networks for review and action. The capability to provide accurate coordinates and error bounds for an object of interest in a UAS video stream has many applications both civilian and military. The coordinate can be used to direct fire, rescue, pinpoint landing, or other action depending on the nature of the target. Targeting methods currently employed by SUAS lack the desired accuracy and do not provide a confidence assessment through error bounding. To remedy these deficiencies, the ACTD has engaged Draper Laboratory and AeroVironment Inc. (AV) to assist in developing and evaluating the military utility of new SUAS targeting capabilities. Under this program, Draper and AV are implementing a system to demonstrate improved targeting from a Raven-B [1], a 4.2 pound tactical SUAS that is widely fielded throughout the Army, Marine Corps, and Special Operations Forces (SOF). The Draper/AV system, called AVTargeting, addresses the first component of targeting, providing MGRS coordinates with increased accuracy and error bounds. AVTargeting is based on visual feature tracking, line-of- sight calculation, and Kalman filtering developed by Draper Laboratory for autonomous, vision-aided navigation [6]. The filter is adapted for use in targeting. A new user