The Future Impact of Unmanned Systems

According to the DOD Unmanned Systems Roadmap 2013-2038, it is expected that the US military will invest $223.9 million in UGSs from 2014 to 2018.  The amount of investment is far less than UMSs and UASs for the same period.  However, the level of impact UGSs may have on society may not directly correlate to the amount of money the US military is expected to invest. 

Google Driverless Car

The civilian sector has an interest in UGSs.  Google has been conducting research in self-driving cars for several years, and according to Dataconomy, “Google expects to have the prototypes ready for public use between 2017 and 2020” (Shad, 2014).  Nissan, Tesla, General Motors, and Ford are also conducting research on self-driving cars and most of the companies plan to have vehicles on the road by 2020.

            The DOD Unmanned Systems Roadmap 2013-2038 indicates that the US military will invest $1.96 billion in UMSs from 2014 to 2018.  UMSs are valuable assets to the military as they compliment current submarine fleets and provide new capabilities.  According to the US Navy, “UUVs increasingly will support anti-submarine warfare operations” (US Navy, 2014).  Captain Paul Ims, the UUV program manager for the US Navy stated, “UUVs and the mission capabilities these systems will deliver are integral components of naval transformation” (Ims 2014). 

          

BlueFin Robots UUV

  The civilian sector has some interest in UMSs.  Oil and gas companies are interested in UUVs to survey ocean floors.  Further, they are inserted in ROVs to inspect underwater drilling operations.  Salvage companies are interested in ROVs to locate and inspect areas of interest.  Researchers and scientists use all available UMS technologies to study maritime environments.  Security companies use USVs for port security.  The overall impact UMSs will have on the civilian sector will be less than that of the UGS promise of self-driving cars.  

            The DOD Unmanned Systems Roadmap 2013-2038 shows that the US military will invest $21.669 billion in UASs from 2014 to 2018.  The large investment in UASs is likely due to President Obama advocacy for drones on the battlefield.  In a speech to the National Defense University President Obama stated, “let us remember that the terrorists we are after target civilians, and the death toll from their acts of terrorism against Muslims dwarfs any estimate of civilian casualties from drone strikes” (Obama, 2014).  The military is becoming increasingly reliant on UASs to conduct airstrikes. 

           

Northrop Grumman X-47B

The FAA currently makes it extremely difficult for civilian UAS companies to provide services.  The FAAs inability to create legislation in the dynamic world of UAS is stalling job growth.  According to the Associated Press, a UAS study has “predicted more than 70,000 civilian jobs would develop in the first three years after the FAA loosens restrictions on U.S. skies” (Kolpack, 2013).   The FAA is expected to establish new regulations in 2015.  The overall impact of UASs in the civilian sector will be enormous. 

            In conclusion, I believe UASs will have the greatest impact on society over the next two decades.  The amount of money the DOD is investing in UASs will not only transform military aviation, but will create thousands of jobs for defense contractors.  Additional jobs will be created after the FAA creates sound UAS legislation.  I expect to see UAS delivery services, police drones, agriculture systems, pollution monitoring, news reporting, and much more.  I hope the long-term applications of UAS technology can revive the dream of the flying car.    

References:

DataConomy (2014). Google’s Self-Driving Cars Expected in 2017. [ONLINE] Available at: http://dataconomy.com/google-self-driving-cars-expected-in-2017/. [Last Accessed 19 December, 2014].

Kolpack, Dave (2014). Where's the Future Aviation Boom? Drone Jobs. [ONLINE] Available at: http://jobs.aol.com/articles/2013/12/12/wheres-the-future-aviation-boom-drone-jobs/. [Last Accessed 19 December, 2014].

US DOD (2013). Unmanned Systems Integrated Roadmap FY 2013-2038 . [ONLINE] Available at: http://www.defense.gov/pubs/DOD-USRM-2013.pdf. [Last Accessed 19 December, 2014].

US Navy (2014). US Navy Unveils UUV Master Plan. [ONLINE] Available at: http://www.navy.mil/navydata/cno/n87/usw/issue_26/uuv.html. [Last Accessed 19 December, 2014].

Kosmos 2499

The article, “That's No Moon! Did Russia Deploy An Experimental Killer Satellite?” by Tyler Rogoway, discusses an application of unmanned space-based systems I had not yet considered.  I came across the article this week on my iPhone’s news feed and I thought it would be perfect for this week’s post.  The article does not take a stance on human based exploration, but instead focuses on a possibly new area of unmanned space based warfare. 

           

Rokot/Briz-KM Launch on May 23, 2014.

Kosmos 2499 is the satellite designation for an unknown object launched by the Russian Federation on May 23, 2014.  The three stage Rokot/Briz-KM orbital carrier launched a payload of three Russian military communication satellites:  Kosmos 2496, Kosmos 2497, and Kosmos 2498.  However, shortly after launch the US Government noticed strange radar returns.  According to the BBC,  “the US military initially classified the object as debris, but it then emerged that the Russian government had told the United Nations the launch had sent four satellites into orbit rather than three”  (Rincon, 2014).

            Astronomers from around the world reported that shortly after launch, Kosmos 2499 performed a series of unusual powered maneuvers to change its orbit.  On November 9, the object approached an inactive stage of the rocket that initially launched it into orbit.  According to satellite observer Robert Christy, the Kosmos 2499 got within a few meters of the rocket stage.      

The official Moscow Institute of Physics & Technology website stated that the satellite was designed to test experimental plasma propulsion engine ion thrusters.  Rogoway speculates that the Kosmos 2499 may be Russia’s answer to the US Air Force X-37B.  The Moscow Times article, “Expert Says Russia, China and U.S. All Working on Satellite Killers” quotes Christy as saying:

Autonomous rendezvous by small satellites has always been considered a useful capability, for purposes of resupply, repair, inspection or even negation. … The fact that the recent Chinese and Russian experiments have been done with no official announcements, and appear independent of already existing [civilian] rendezvous systems, does suggest to me they are not for peaceful purposes.

Rogoway classifies the Kosmos 2499 as an inspector satellite that he defines as a maneuverable space vehicle that can approach other satellites for both passive and active purposes.  The purposes may range from taking photographs or measurements of satellites, targeting transmissions, jamming, hijacking, or complete satellite destruction.  The full ranges of possibilities are vast.

The X-37B

 However, if the theories outlined in the article are close to accurate, there is a bright side.  The technology used in Kosmos 2499 or possibly the X-37B may someday be used to advance technologies needed to refuel or repair orbiting satellites.  Servicing satellites in geosynchronous orbit is best suited as an unmanned endeavor because astronauts outside the protection of Earth’s magnetic field would be exposed to dangerously high levels of radiation.  The ability of unmanned systems servicing satellites will save a tremendous amount of money and time.

The equal advancement of both manned and unmanned space systems will yield the best results the future of the human race.  If early aviation pioneers had access to wind tunnels, computer simulations, and drones, technology would have developed much fast and fewer people would have lost their lives on the way.  Our technological state has enabled us to let probes and rovers lead the way to explore new worlds.  The data collected by unmanned space systems will one day be used to send humans to new worlds.  

References

Атомная лицензия ГАН (2014). Object 2014-28E. [ONLINE] Available at:http://www.sdelanounas.ru/blogs/55092/. [Last Accessed 21 November, 2014].

BBC (2014). Russia Tests 'Satellite Catcher'. [ONLINE] Available at:http://www.bbc.com/news/science-environment-30097643. [Last Accessed 21 November, 2014].

Bodner, Matthew (2014). Expert Says Russia, China and U.S. All Working on 'Satellite Killers'. [ONLINE] Available at: http://www.themoscowtimes.com/business/article/russia-s-isn-t-the-only-satellite-killer-in-space/511403.html. [Last Accessed 21 November, 2014].

Rogoway, Tyler (2014). That's No Moon! Did Russia Deploy An Experimental Killer Satellite?. [ONLINE] Available at: http://foxtrotalpha.jalopnik.com/thats-no-moon-did-russia-deploy-an-experimental-killer-1661535449. [Last Accessed 21 November, 2014].

The SnotBot: UASs for Whale Health

The BP Deepwater Horizon oil spill occurred on April 20, 2010 and leaked oil into the Gulf of Mexico near the Mississippi River Delta until July 15, 2010.  The manmade disaster spilled a volume of 210,000,000 gallons of oil and affected an area of 68,000 square miles.  The total damage to marine life is still unknown. 

The Ocean Alliance is a Gloucester, Massachusetts based organization founded in 1971 that “strives to increase public awareness of the importance of whale and ocean health through research and public education” (Ocean Alliance, 2014).  The Ocean Alliance believes that the dispersants used by BP’s oil cleanup efforts were designed not to mitigate the effects of the oil on sea life, but rather to hide the oil.  The Ocean Alliance believes oil from that spill is still having adverse effects on marine life in the Gulf of Mexico. 

In 2013, the Ocean Alliance teamed with Sea Shepard Conservation Society under a program called Operation Toxic Gulf.  The ongoing operation aims to study the long-term effects of the oil spill on whale life.  The operation is pioneering new research techniques to study whales without causing harm or stress of any kind.  In order to accomplish this, the organizers of Operation Toxic Gulf turned to the Olin School of Engineering in Needham, Massachusetts.  In 2014, the school unveiled their whale studying creation, the SnotBot.

The SnotBot is a small multicopter Unmanned Aerospace System (UAS) that will collect blow samples from the blowholes of whales.  The UAS is made to launch from a whale-watching vessel as soon as a surfaced whale is spotted.  It will immediately fly to the blowhole of a whale while under the control of an operator from the vessel. The SnotBot will then collect a sample of the blow as the whale exhales via a surgical sponge mounted on the bottom of the UAS.  The SnotBot will then return to the vessel where the sample will be cataloged and later analyzed.

The SnotBot in action

The blow samples from whales contain lung lining and mucus that will be analyzed to collect biological data such as stress hormones, bacteria, toxins, viruses, and DNA.  However, for Operation Toxic Gulf to determine if whales in the Gulf of Mexico are experiencing health problems, the same datasets must be collected all over the world.  This is where the SnotBot is extremely beneficial.

Before the use of SnotBot, whale blow had only been collected using fixed wing aircraft that would follow spotted whales.  The aircraft had to fly low and slow, and it was theorized that their noise would cause the whales stress, therefore throwing off the hormone levels on collected samples.  The old approach also proved to be difficult and expensive.

The Ocean Alliance has reduced the total cost of the SnotBot to $2,850 per unit.  The cost includes a First Person View (FPV) camera for operations beyond the line of sight.  Additionally, it contains a separate onboard camera for high definition video recording.  The low cost will allow researchers worldwide to collect and share similar whale data. 

The Ocean Alliance has one last hurdle before using the SnotBot to study whales, at least in the United States.  The FAA currently does not allow aircraft to fly less than 1,000 feet over a whale.  Researchers at the Ocean Alliance and the Olin School of Engineering conducted SnotBot testing on inflatable whales.  The data was included in a research study that argued the SnotBot would not cause harm or stress to whales.  The study was included in their application for an FAA Certificate of Authorization or Waiver (COA).  The COA for the SnotBot has not yet been approved.

 References:

Olin College of Engineering (2014). Saving Whales: One Drone at a Time.  [ONLINE] Available at:http://www.olin.edu/news-events/2014/saving-whales-one-drone-time/.  [Last Accessed 15 November, 2014].

Ocean Alliance (2014).  SnotBot Archives.  [ONLINE] Available at:http://www.whale.org/tag/snotbot/.  [Last Accessed 15 November, 2014].

OpenROV: A UMS for Everyone!

OpenROV is an open-sourced remotely operated miniature submarine aimed at making underwater exploration and education cheap and accessible to everyone.  The developers behind the project are do-it-yourself (DIY) enthusiasts Eric Stackpole, David Lang, and Matteo Borri.  The project was introduced on the Kickstarter website in 2012 in an effort to raise $20,000.  The project exceeded its Kickstarter funding goal by $91,622, and in 2013 ended its funding campaigns with over $1.3 million.  It was not until late 2013 that OpenROV v2.6 began to take orders on the OpenROV website.  It is expected that OpenROV v2.7 will become available in 2015.  

OpenRov

OpenROV is not the next generation of military UMS.  It does not use state of the art sensors, processors, or navigation systems.  It does not reach incredible depths nor does it maneuver at high speeds.  However, OpenROV is inexpensive.  The OpenROV Kit currently retails for $849.  It is easily obtainable by educational institutions and individuals with an interest in exploring.

OpenROV v2.6 is small, with dimensions of 15cm x 20cm x 30cm.  Eight C batteries provide approximately 1.5 hours of runtime.  The onboard processor is a low power, open-sourced, Linux based, BeagleBone Black.  It connects to a standard PC via a 100 meter tether cable.  It has an onboard high definition wide-angle camera with a tilt function, and LED lighting for low-light environments.      

            OpenROV represents the future of UMS because its low price significantly reduces the barrier to entry for underwater exploration.  The exploration of underwater environments is no longer limited to governments, large corporations, or researchers with large grants.  The OpenROV website has dozens of examples of how the platform is employed all over the world.  A middle school class in Hawaii purchased an OpenROV to study coral health after hurricanes.  A concerned citizen in Seattle used an OpenROV to help show that the city was dumping millions of gallons of untreated sewage and storm water into the cities waterways.  The city of Sydney, Australia hosted an open lab/hackerspace to innovate OpenROV solutions in the protection of marine life.  Portugal used an OpenROV to conduct a study of biological invasions by non-indigenous species.  The uses for OpenROV are endless.

            The open-sourced community allows OpenROV users and developers to share code, ideas, and answer technical questions.  Modifications are commonplace in the open source community.  The BeagleBone Black contains 2 x 46 pin headers, which allow the connection of third party digital sensors.  Code found in the OpenROV online repositories can bring third party sensors to life, or they can provide insight for users to do their own programming.  Further, 3D printing has been used in physical modifications.  Modifications allow the platform to operate outside of its initial design.

           

OpenRov Breakdown

OpenROV can interface with a computer by way of a LAN connection and a modern web browser.  Once the OpenROV is connected to a computer via LAN cable, its IP address is entered into a web browser and connectivity is achieved.  The operating system of the computer is not a factor, meaning it can be Windows, Linux, OSX, or anything else.  Users may choose to configure video game style controllers for easy operation.

            OpenROV gives tinkerers a platform to inexpensively experiment and solve underwater problems.  The lessons learned from OpenROV might one day be able to provide cost saving insight into the development of more expensive military UMS.  I believe that opening UMS to everyone is the future of UMS technology.    

References

Chung, Philip (2014).  OpenROV.  [ONLINE]  Available at: 

http://scinipenguin.mlml.calstate.edu/?p=938.  [Last Accessed 07 November 2014].

OpenROV (2014). Underwater Exploration Robots. [ONLINE] Available at: 

http://www.openrov.com/.  [Last Accessed 07 November 2014].

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].

sUAS Sense and Avoid

In order to safely operate an aircraft of any type, it is necessary to detect incoming obstacles such as birds, buildings, other aircraft, weather, etc.  Pilots in manned aircraft are able to visually search and assess the airspace around their aircraft.  However, due to latency and unwanted breaks in communication, Unmanned Aircraft Systems (UASs) flying beyond an operator’s line of sight cannot accurately search and assess their airspace.

ICAO Cir 328, Unmanned Aircraft Systems (UAS)

Many large UASs have been outfitted with Sense and Avoid (SAA) systems to fill this gap.  “SAA functions to protect against collisions with other aircraft as well as various other hazards” (Zeitlin, 2010).  SAA in large UASs commonly use information from onboard transponders, Automatic Dependent Surveillance – Broadcast (ADS-B), optical sensors, LIDAR, and Radar to autonomously avoid threats.  However, small UASs (sUASs) (55 pounds or less) are not commonly outfitted with SAA systems due to weight and power constraints.

RADAR Based Collision Avoidance for Unmanned Aircraft Systems (2013) is a doctorate dissertation by Allistair A. Moses, from the Daniel Felix Ritchie School of Engineering and Computer Science, University of Denver, which provides insight on sUAS SAA technology.  Moses demonstrates the feasibility of a self-contained radar based collision avoidance system that weighs 304 grams (0.670205 pounds).  The SAA system was outfitted on an Align TRex450 Helicopter with a flying weight of 900 grams (1.98416 pounds).

RADAR Based Collision Avoidance for
Unmanned Aircraft Systems

The power consumption of the SAA is 5.8 W, with an input voltage of 5.6 VDC.  Its transmit frequency is 10.5 GHz with a transmit bandwidth of 5MHz.  It has a transmit power of 0.4mW and utilizes Frequency Shift Keying Continuous Wave Modulation (FSKCW).  FSKCW is a square wave modulation that is used to reduce background noise caused by terrain.   

The entire SAA system was built from scratch except for the antenna. The SAA uses a custom radar suite capable of detecting other aircraft.  The radar uses micro Doppler signal acquisition and identification consisting of quadruple transmit receive modules.  “This allows for the ready implementation of what they describe as a ‘Reactive Collision Avoidance Algorithm’ wherein the host vehicle steers away from the quadrants with the highest returned signal energy” (Moses, 2013).   

University of Denver faculty advisor Dr. Matt Rutherford stated, “in our field tests we were able to detect and identify targets of the size roughly equivalent to UAV at about 100 meters or 300 feet”  (Spendergast, 2014).  Researchers at the university are continuing to work on increasing the SAAs range.  In my opinion, a 100-meter SAA range on low power system weighing just over half a pound is impressive.  It should be noted that this technology could be up scaled to the effect that a larger sUAS with a SAA drawing more power can result in a longer detection range.     

Reference

Moses, Allistair A. (2013). RADAR Based Collision Avoidance for Unmanned Aircraft Systems. [ONLINE] Available at: http://digitaldu.coalliance.org/fedora/repository/codu%3A66898/Moses_denver_0061D_10839.pdf/Moses_denver_0061D_10839.pdf. [Last Accessed 28 February, 2015].

Pendergast, Stephen (2014). DU2SRI Miniature Radar May Give SUAS Sense and Avoid. [ONLINE] Available at: e.g. http://www.microsoft.com. [Last Accessed 28 February, 2015].

Zeitlin, Andrew D. (2010). Sense & Avoid Capability Development Challenges. [ONLINE] Available at: http://ieeexplore.ieee.org.ezproxy.libproxy.db.erau.edu/stamp/stamp.jsp?tp=&arnumber=5631723&tag=1. [Last Accessed 28 February, 2015].