GPS-Free Robotic Explorers

The Institution of Engineering and Technology (IET) released an article on September 25, 2015 titled, “Robotic Explorers”.  The article summarizes a recent research paper titled “Multi-UAV-Based Stereo Vision System Without GPS for Ground Obstacle Mapping to Assist Path Planning of UGV”.  Jin Hyo Kim, Ji-Wook Kwon, and Jiwon Seo at the Yonsei University in Incheon, Korea authored the research paper.  The article and paper discuss an Unmanned Ground Vehicle (UGV) navigation technique that does not rely on a Global Positioning System (GPS) signal or other expensive navigation equipment.  The technique pairs a UGV with Unmanned Arial Systems (UASs) in the form of multicopters to provide imagery to the UGV aiding in the calculation of an optimum route.  

The agents of the prototype UGV/UAV cooperative system.

Decreasing UGVs dependency on GPS can increase their overall reliability.  The Defense Research Projects Agency (DARPA) understands the benefits of GPS free navigation and has funded five projects which include Adaptable Navigation Systems (ANS), Microtechology for Positioning, Navigation, and Timing (Micro-PNT), Quantum-Assisted Sensing and Readout (QuASAR), and the Program in Ultrafast Laser Science and Engineering (PULSE).  While the DARPA projects are ambitious, the solution offered by IET is low cost and relies on off the shelf technology.

The cooperative UGV/UAS uses multicopters equipped with off the shelf cameras for UGV path planning.  The cameras extrapolate terrain depth information without the use of Light Detection and Ranging (LIDAR), radar, or sonar.  LIDAR, radar, and sonar are limited to line-of-sight and cannot perceive objects behind obstacles.  This limits the path planning of UGVs.

The proposed UGV/UAS system “uses stereo-vision depth sensing to provide the obstacle map, and other image processing techniques to identify and track all the agents in the system, relative to each other and the environment, so GPS information is not needed”  (IET, 2014).  The stereovision mentioned is sometimes referred to as computer stereovision and is the extraction of 3D information obtained by (in this case) Charged Coupled Device (CCD) cameras.  The extracted information compares the images taken from two vantage points, resulting in depth information.  The system uses two multicopters to provide two vantage points.  

All testing of the corporative UGV/UAS has been conducted in laboratory settings.  During trial testing, the system was able to detect and avoid 42 obstacles in a series of seven tests.  However, the system detected 17 false alarms.  False alarms occur when the system detects obstacles that do not exist.

The article does not mention field tests of the cooperative UGV/UAS.  Field-testing will surely present many challenges.  Adverse weather conditions such as rain, snow, high winds, or sandstorms may limit the CCD computer stereovision system.  Further, the ground vehicles will be limited to the accessibility of the UAS.  Tunnels, caves, and forests will limit the UGV/UAS line of sight relationship. 

The cooperative UGV/UAS system shows promise for future application.  The importance of cost savings in UGVs is high.  According to the United States Department of Defense (DOD) “Unmanned Systems Integrated Roadmap, FY 2013-2038”, UGVs are expected to receive less funding than all other types of Unmanned Systems (USs).  However, the demand for military UGVs is high.  Applications of military UGVs will range from Explosive Ordnance Disposal (EOD); Chemical, Biological, Radiation, Nuclear (CBRN); engineering, logistics, transport; Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISR); and command and control.  In order for the DOD to meet the future demand for UGVs, cost effective measures such as the proposed UGV/UAS in “Robotic Explorers” are needed to accomplish milestones.

References

Defense Advanced Research Projects Agency (2014).  Beyond GPS:  5 Next Generation Technologies For Positioning, Navigation and Timing (PNT). [ONLINE]  Available at:  http://www.darpa.mil/NewsEvents/Releases/2014/07/24.aspx.   [Last Accessed 01 Nov 2014].

Department of Defense (2013). Unmanned Systems Integrated Roadmap FY 2013-2038. [ONLINE]  Available at: http://www.defense.gov/pubs/DOD-USRM-2013.pdf.  [Last Accessed 01 Nov 2014].

Institute of Technology and Engineering (2014). Robotic Explorers.  [ONLINE]  Available at:  http://www.theiet.org/resources/journals/eletters/5020/robotic-explorers.cfm.  [Last Accessed 01 Nov 2014].

Kim, Jin Hyo; Kwon, Ji-Wook; and Seo, Jiwon (2014).  Multi-UAV-Based Stereo Vision System Without GPS for Ground Obstacle Mapping to Assist Path Planning of UGV.  [ONLINE]  Available at: http://media.proquest.com.ezproxy.libproxy.db.erau.edu/media/pq/classic/doc/3464536441/fmt/pi/rep/NONE?hl=&cit%3Aauth=Kim%2C+Jin+Hyo%3BKwon%2C+Ji-Wook%3BSeo%2C+Jiwon&cit%3Atitle=Multi-UAV-based+stereo+vision+system+without+GPS+for+ground+obstacle+...&cit%3Apub=Electronics+Letters&cit%3Avol=50&cit%3Aiss=20&cit%3Apg=1&cit%3Adate=Sep+25%2C+2014&ic=true&cit%3Aprod=ProQuest+Advanced+Technologies+%26+Aerospace+Collection&_a=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%3D&_s=CUIVr66MaiROeSvd6inROLM4BqI%3D.  [Last Accessed 01 Nov 2014].