The RQ-11 Raven is a small hand launched unmanned aircraft system (UAS) produced by AeroVironment, Inc capable of performing tactical intelligence, surveillance, and reconnaissance (ISR). It is currently employed by the United States’ armed forces as well as allied partners and commercial entities. The UAS is “operated by two Soldiers and has a rucksack-portable design. No specific military occupational specialty is required” (U.S. Army, 2014). The Raven unmanned aircraft (UA) operates up to a range of 10 km from the ground control unit (GCU) commanding it (AeroVironment, 2016), however, the UA is capable of transferring command responsibilities to another GCU located beyond its standard range (Headquarters, 2006). AeroVironment utilizes a common ground control station for their Wasp AE, Raven, and Puma UASs (2016). By using a common ground control station, AeroVironment reduces the training burden for operators using multiple weapon systems, or transferring between UASs. This research focuses on the Raven’s use of this ground control unit.
The Raven ground control station (GCS) has multiple interfaces. This configuration helps to support varied conditions the users may find themselves in. The first interface is the hand controller which resembles a personal gaming system. The hand controller consists of a unit with a “video screen with text overlays, a joystick, a toggle switch, a four-way “hat” control and four buttons (two on the front, two on the rear)” (Stroumtsos, Gilbreath, & Przybylski, 2013). Being a hand held unit, the display is limited in size and what can be displayed. This unit can toggle between flight modes, zoom the camera, and display video (2013). Given the limited number of input devices and displays, interacting with the UA becomes difficult. Another difficulty in using the handheld GCS is the requirement for using a hood to block out extraneous glare. While this makes seeing the display easier, it removes all situational awareness of what is happening around the operator making them more vulnerable. AeroVironment offers another GCS solution to help negate some of the drawbacks of the handheld GCS.
The laptop interface utilizes the capabilities of the handheld GCS and adds increased display and input features. The laptop connects to the handheld GCS via an ethernet cable. This interface provides the ability to graphically display much more detail such as graphical heading, graphical waypoints, and the above ground altitude of a single waypoint (Stroumtsos, Gilbreath, & Przybylski, 2013). Stroumtsos, Gilbreath, and Przybylski make the statement that “All of the shortcomings of the current GCS can be addressed using a laptop-based GCS with the appropriate software” (2013). This is a very interesting design premise. While software developers are capable of outstanding work, this statement may overstep the realistic bounds of software. However, the Space and Naval Warfare Systems Center (SPAWAR) created a multi-robot operator control unit (MOCU). The goal of this system is to integrate a single control unit for use with unmanned systems independent of which domain that system is operating in. This utilizes the laptop interface and an X-Box 360 controller. Both of these pieces of hardware are probably familiar to the operators which helps reduce the training burden. A student operator only needs to learn the software portion of the system. Although as the authors say anything can be addressed with the right software, there are other human factors issues as stake in the Raven’s GCS design.
The U.S. Army field manual on UAS operations acknowledges “a single factor such as human error or materiel failure seldom is the only cause of an aviation accident. Accidents are more likely to result from a series of contributing factors” (Headquarters, 2006), however, immediately following this paragraph it places human factors as the first bullet under “Accident Causes.”
One human factor issue is the lack of situational awareness when an operator is utilizing the handheld GCS. The operator is unable to monitor his or her surroundings while there head is down looking inside the hood. Additionally, some operators describe the character based symbology as difficult to understand. One may argue that the Predator or Reaper operators also do not have situational awareness of what is occurring outside their GCS, however, the big difference is the distance between the UA and the GCS. The Raven operators are within 10 km of the area of interest they are surveilling. In addition, the switching between hooded view and returning to the real world “the change in brightness causes loss of vision for 5-15 seconds” (Stroumtsos, Gilbreath, & Przybylski, 2013). This time lost could be crucial during an engagement with the enemy. Since the need for the hood results from a dim screen a couple potential solutions arise such as operating the handheld GCS from within a shelter. This will likely reduce the man-portability of the system if a shelter is also required. Another option is a tinted eyeglass, goggle, or contact lens. A study conducted in 2005 looked at the effects of absorbtive contacts lenses on 4 subjects with retinal dystrophy. When the individuals were given the lenses, “all of them expressed great comfort and improvement of their ability to use their remaining vision more effectively” (Fernandes, 2005). A final option is to provide a variable brightness on the handheld GCS in order to overcome daylight. Any of the solutions, or a combination of them, will increase the operators ability to maintain situational awareness of their surroundings.
Another issue that needs to be addressed is the specificity of the harware to a particular airframe. The SPAWAR report states, “the majority of GCS hardware is vehicle specific and cannot be used to control other vehicles or used for any other purpose” (Stroumtsos, Gilbreath, & Przybylski, 2013). This means an operator that flies one UA is unlikely to be able to switch UAs in the field because of different configurations and hardware. In battle there may come situations where the Raven is not available, but other UASs are without operators. Given a common GCS, one operator could be reasonable familiar with the use of another UAS in an emergency. AeroVironment has begun to address this issue with the common GCS which their UASs Wasp, Raven, and Puma all utilize. The U.S. Navy is also adapting a common GCS in the MOCU system. The benefit of the MOCU system is that it will allow one type of GCS to operate robots below, on top, and above the sea.
The Raven is one of the most popular small UASs in use today. It has multiple GCS configurations which can be adapted depending on the environment in which it is being employed. There are issues with the differing interfaces, however, the manufacturer of the system as well as some of the users are working to overcome them in order to apply the Raven’s capabilities to the greatest extent possible.
References
AeroVironment, I. (2016). AeroVironment. Retrieved from UAS: RQ-11B Raven: http://www.avinc.com/uas/small_uas/raven/
Fernandes, L. C. (2005). Absorbtive and Tinted Contact Lenses for Reduction of Glare. Vision 2005 - Proceedings of the International Congress, (pp. 534-538). London.
Headquarters, D. o. (2006). Army Unmanned Aircraft System Operations. Washington DC: Headquarters, Department of the Army.
Stroumtsos, N., Gilbreath, G., & Przybylski, S. (2013). An Intuitive Graphical User Interface for Small UAS. San Diego: Space and Naval Warfare Systems Center Pacific.
U.S. Army. (2014, November 4). Retrieved from RQ-11B Raven Small Unmanned Aircraft Systems (SUAS): http://www.army.mil/article/137604/
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