Unmanned Aircraft System Beyond Line of Sight

 Unmanned Aircraft System Beyond Line of Sight

A Review of the MQ-1B Predator

            Many unmanned aircraft systems (UASs) can be operated through use of Line of Sight (LOS) operations; however, there are several UASs that also operate Beyond the Line of Sight (BLOS) missions.  Oftentimes, operators utilize a combination of both LOS and BLOS operations in order to successfully complete their mission.  As such, it is of interest to discuss both the advantages and disadvantages of LOS versus BLOS as well as how they are operated.

For the purposes of this review, the LOS and BLOS operations of the MQ-1B Predator will be discussed.

            The MQ-1B Predator is a remotely piloted aircraft with the primary goal of intelligence collection and the secondary goal of dynamic execution targets.  As such, the MQ-1B Predator is armed, multi-mission, medium-altitude, long-endurance and remotely piloted (US Air Force, 2010).  Due to the nature of its mission, the MQ-1B Predator is equipped with task-necessary infrastructure to support operations that includes the following: four sensor/weapon equipped aircraft, ground control station, and Predator Primary Satellite Link (US Air Force, 2010).  Additionally, the system requires maintenance and operations crews in the case of missions that require 24-hour operations.

 These crews are comprised of a pilot (tasked with mission command and aircraft control) and an enlisted aircrew member (tasked with sensor/weapon operations and mission coordination as necessary).  Dependent upon the stage of the mission, the crews will either remotely control the aircraft from the ground control station (GCS) through use of line-of-sight data link or satellite data link for beyond line-of-sight if the aircraft is too far out (US Air Force, 2010).  In the case of BLOS missions, the MQ-1B Predator is equipped with an infrared sensor, color daylight TV camera, laser designator/illuminator, and an image-intensified TV camera as well (UAS Air Force, 2010).  The cameras allow for viewing of full-motion video from the each imaging sensor, which can then be streamed independently or combined together into one video stream.  Moreover, the Predator can also utilize laser-guided missiles (it is equipped with two Hellfire missiles) for target execution.  These are operated somewhat differently when the aircraft is in the LOS versus BLOS.

As previously mentioned, one Predator is operated by a crew that consists of a pilot and two sensor operators.  The pilot maneuvers the aircraft using controls that transmit their commands by way of a C-Band-Line-of-sight data link (US Air Force, 2010).  This differs from how the Predator is operated when the aircraft is beyond the ling of sight (see Figure 1).  In the case of BLOS missions, a Ku-Band satellite link is used instead in order to communicate commands and responses to and from the satellite and the UAV (US Air Force, 2010).  Particularly, orders in the form of data are transferred from an L-3 Com satellite data link system to the UAV; further, the information received from the UAV, such as video or images, are used by the pilot and crew to make decisions regarding how to maneuver the UAV (US Air Force, 2010).  This alters from line of sight operations in that it adds a few more steps.

With the line of sight operations, there is less room for signal disruption since there is a direct link from the Ground Control Station to the Predator.  However, when piloting in beyond line of sight operations, one disadvantage is that there is the additional step of the satellite relay.  In this case, the data is picked up by the Predator, sent to the Satellite, and transferred back to the Satellite Uplink Vehicle; a benefit to this method is that this data signal can also be sent to other military facilities (Valdes, 2004).  As one can guess, the switch from LOS to BLOS could consequently result in human factors issues particularly in regards to conduct operations.

Figure 1. Predator UAV Communication System.   This figure illustrates the design of the Predator UAV Communication System. It is composed for three main parts: 1) Ground Control Station 2) Predator Drone and 3) Satellite Relay.  The satellite relay serves as communication between the UAV and the GCS particularly in beyond line of sight missions. Figure was borrowed from Valdes (2004).

            One common human factors issue that occurs when a manned aircraft pilot makes the switch to a UAS is that pilots must now rely heavily on cameras to gain situational awareness.  Oftentimes, this may feel as though the pilot has to look through a narrow tunnel when accessing the video stream.  This significantly limits their ability to gain situational awareness.  Additionally, fatigue is a common human factors issue associated with piloting UASs.  Although this is seen with manned aircraft as well, it seems to be found in a different form.  UAS pilots must essentially stare at a monitor for long hours, which can result in boredom and fatigue.  Manned pilots do not have to do this, although they do suffer from other triggers of fatigue such as jet lag.  There are also human factors issues when switching from LOS to BLOS operations of UASs.

            LOS operations are a little more closely associated with manned aircraft human factors in that the pilot has a more physical notion of situational awareness.  Since they can visually have eyes on their aircraft it is easier to detect a nearby threat or obstacle and take decisive action.  However, this is more difficult to do when piloting BLOS.  In BLOS operations, the pilot and crew rely significantly on the data transmissions they receive from the satellite.  This means that any delay or error in the transmission may not be detected until it is too late, which could result in a mishap.  This also limits the crew’s situational awareness and makes them very dependent upon the satellite data stream.  The advantages of UAS BLOS however can serve as great potential for commercial industries.

            Some commercial applications for UAS BLOS can involve filming movies.  This is something that is becoming more common now as films are more and more often taking place in remote locations.  Additionally, shipping industries and retail industries can also take advantage of UAS BLOS for shipment of goods and products to users (this is currently being explored by Amazon).  Conclusively, UAS BLOS has its advantages and disadvantages; although it is subject to some unique human factors issues, the benefits of UAS BLOS seem to outweigh any negatives.

References

U.S Air Force. (2010, July 10). MQ-1B Predator. Retrieved November 14, 2014, from  

http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104469/mq-1b-predator.aspx

Valdes, Robert. (2004, April 1). How the Predator UAV Works. Retrieved November 14, 2014,

from http://science.howstuffworks.com/predator.htm