UAS Beyond Line of Sight Operations

The ScanEagle is a fixed wing, long endurance Unmanned Aerial Vehicle (UAV) developed by Insitu, a subsidiary of Boeing.  With a 3.1 meter wingspan, 1.4 meter length and a 20 kilogram mass, it utilizes a heavy fuel (JP-5 or JP-8) engine to fly at cruising speeds of 50-60 knots with a maximum speed of 80 knots (Insitu, 2013).  The ScanEagle has a flight endurance of over 24 hours and a flight ceiling of 5,950 meters (Insitu, 2013). 

The ScanEagle uses a command, control, and communications suite that allows the operator the ability to send and receive signals to the aircraft during Line-of-Sight (LOS) operations and Beyond-Line-of-Sight (BLOS) operations.  Typically LOS command and control (C2) data links use a C Band data link that uses low GHz frequencies for downlink, 3.7-4.2 GHz, and 5.9-6.4 for uplink (Oh, Piegl, & Valavanis, 2008).  C Band is strategically chosen for LOS C2 because the low GHz frequencies are less affected by extreme weather conditions (Oh, Piegl, & Valavanis, 2008).  However, the ScanEagle uses UHF for LOS command and control; and a Common Data Link (CDL) for BLOS operations.  CDL is a jam resistant spread spectrum digital microwave link only used by the military. 

ScanEagle’s Satellite-based communications (SATCOM) C2 platform used for BLOS operations utilizes a 900 MHz or 1.3 GHz L band frequency (Wilke, 2007).  Due to the remote applications of the ScanEagle, the C3 data link infrastructure is small and portable.  The long range antenna uses a 1.8 meter circular polarized dish with an effective range of 50-100 kilometers (Wilke, 2007).  These terminals also have the ability to link with one another allowing C3 capabilities to multiple UAVs simultaneously and the ability to pass off C3 capabilities from one GCS to another.  The L-band antenna on the UAV allows for direct analog video downlink to Insitu’s portable GCS (Rover III) or other remote video terminals.  The ScanEagle operation requires seven personnel: Analyst (1), Operators (3), Maintainers (2), and Mission Commander (1) (Wilke, 2007).

In regards to military operations, the advantage of BLOS operations is that it allows operators to be a great distance from the actual UAV; keeping the operator out of harms way and undetectable.  Two disadvantages of BLOS operations is that it is easier to encounter a lost link situation and operators have low situational awareness.  The unique operations of the ScanEagle is that the LOS operations are done autonomously and the BLOS operations are done manually; it’s typically the other way around.  This type of operation arises more human factor elements by the lower situational awareness of BLOS flight. 

            There are many potential commercial applications for BLOS UAV operations.  One in particular, is the application that Beyond Petroleum (BP) was just presented a Certificate of Authorization from the Federal Aviation Authority for and that’s the monitoring of oil pipelines in Alaska.  The extreme conditions and remoteness of the pipelines make a perfect prospective for BLOS operations.

References

Insitu. (2013). ScanEagle System. Retrieved from insitu.com: http://www.insitu.com/systems/scaneagle

Oh, P., Piegl, L., & Valavanis, K. (2008). Unmanned Aircraft Systems: International Symposium On Unmanned Aerial Vehicles. New York City: Springer.

Wilke, C. (2007, Feburary 28). ScanEagle Overview. Retrieved from csdy.umn.edu: http://www.csdy.umn.edu/acgsc/Meeting_99/SubcommitteeE/SEpubrlsSAE.PDF

UAS integration into the NAS

The Federal Aviation Administration (FAA) has developed a roadmap in order to find a solution to the ever growing National Airspace System (NAS) safety issues.  The FAA's roadmap addresses policies, procedures, regulations, and technologies that will be needed in order for Unmanned Aerial Systems (UAS) to safely fly within the NAS.  The plan is to implement the Next Generation Air Transportation System (NextGen) system in stages between 2012 and 2025.  The goal of the NextGen system is to alleviate the stress and ensure the safety of the increased air traffic and introduction of UAS within the NAS.  According to the FAA's Destination 2025:

"NextGen is a series of inter-linked programs, systems, and policies that implement advanced technologies and capabilities to dramatically change the way the current aviation system is operated. NextGen is satellite-based and relies on a network to share information and digital communications so all users of the system are aware of other users' precise locations (FAA, 2013)."

The implementation of advanced sense and avoid technologies is the main focus on the manned aviation spectrum of the NextGen system.  For the NextGen system to work, all aircraft operating within the NAS will have to be able to effectively maintain a safe distance from each other, called self-separation.  As what is described as the backbone of the NextGen system, Automatic Dependent Surveillance Broadcast (ADS-B), will move Air Traffic Control from radar based system to a satellite derived aircraft location system.  The requirement for ADS-B is planned to be implemented in the United States by January 1st, 2020 (Davidson, 2013).  ADS-B periodically broadcasts data such as, position, altitude, identification, and velocity about the aircraft through an onboard transmitter.  Other aircraft equipped with ADS-B and ATC will be able to see and interpret that data in order to maintain safe distances.

The difficulty that the FAA is facing with integrating UAS into the NAS is ensuring the UAS has the same level of safety that a manned aircraft has.  Without an actual pilot onboard, a UAS will have to utilize sensors in order to “see” objects in the sky.  The integration of ADS-B aboard a UAS will help with aircraft to aircraft position locations, but the ADS-B system does not sense other objects such as buildings, mountains, or trees.  Furthermore, the technology is too bulky and heavy to efficiently be installed in small UAS.  In order to match the safety of a manned aircraft, sense and avoid technology is going to have to be developed and successfully implemented into UAS before the FAA can approve the safety of the aircrafts.

The main human factor that is foreseeable in the future is the lack of training of UAS pilots.  Manned aircraft require extensive training not only to operate the aircraft safely, but to increase awareness of their surroundings.  As more people are getting into the hobby due to a large sUAS influx recently, the lack of skill in pilots is becoming even more apparent.  The public is seeing these sUAS as toys and not the dangerous aircraft that they are.  The FAA can mitigate this issue with a licensing program to fly UAS.  Different classifications can help in reducing the requirements to specifics of the aircraft (size, technology, distance, etc.).  There are already restrictions upon flying model aircraft, but they are loosely regulated and ignored all too often.  If pilots have to earn their right to fly while being taught safe practices, they will be less likely to break the rules and fly dangerously.


References

Davidson, J. (2013, September 23). ADS-B Requirements Coming Into Effect . Retrieved June 20, 2014, from universalweather.com:http://www.universalweather.com/blog/2013/09/ads-b-requirements-coming-into-effect/

FAA. (2013). Integration of Civil UAS in the NAS Roadmap. Retrieved June 20, 2014, from faa.gov: http://www.faa.gov/about/initiatives/uas/media/UAS_Roadmap2013.pdf

UAS GCS Human Factors Issue

I am going to focus on Aerovironment’s Ground Control Station (GCS) which is a common command and control solution for their family of small Unmanned Aerial Systems (sUAS) (Aerovironment, 2014).  The GCS (see Figure 1) is a compact, lightweight handheld piece of equipment designed for military use.  It is dustproof, waterproof and made of a high density plastic built for abuse.  It is designed for mobile use so the small size allows the operator to carry it within a backpack and it sets up in less than two minutes (Aerovironment, 2014).  The interoperability of the GCS allows the operator to use the GCS with the whole Aerovironment’s line of sUAS (Raven, Wasp, and Puma AE). 

Figure 1 – Aerovironment’s Ground Control Station

The GCS incorporates a small screen in order to see real-time video from the air vehicle’s payload cameras.  The GCS can also be embedded as a Remote Video Terminal (RVT), enabling Command Centers or Monitoring Stations the same viewing and analysis capability of the UAV operator (Aerovironment, 2014).  The GCS has the ability to store eighty image captures from the video feed (Aerovironment, 2014).  It allows for manually or autonomous flight operations and can store multiple pre-programmed missions (Aerovironment, 2014).  There are eight modes of operation (Manual, Altitude-Hold, Navigate, Loiter, Home, Loss-of-Link, Follow Me, Autoland).  It utilizes common military batteries which allows for easy integration into the battlefield.

Two human factors that I identified from its design is the exposed display screen and the compact size.  As evident with the smart phone revolution, people have a hard time keeping screens from breaking.  During military operations, the rough and quick handling of these units is just asking for the screen to get damaged.  During remote operations the damage could result in a failed operation unless a spare is present.  Another factor is the small screen.  While the compact size has many advantages in the battlefield, the small screen can put a strain on the operator’s eyes.  During long use, the operator could mistake non-hostiles as targets or make other bad decisions.  The ability to attach a larger screen, such as a “toughbook” would be an ideal solution to the problem.  As for the issue with the screen, a more expensive material to prevent easy destruction or a hard case could help mitigate the issue.

The issues that are present in the manned aviation community that relate to the factors of this GCS is eye strain.  During night operations or long duration missions, bright lights from either instruments or ambient lighting can accelerate fatigue and cause straining on the eyes. 

References

Aerovironment. (2014). UAS: Ground Control System. Retrieved from avinc.com: http://www.avinc.com/uas/small_uas/gcs/