UAS Shift Work Schedule (ASCI 638, 5.6)

This project represents a potential solution for a MQ-1B Unmanned Aerial System (UAS) squadron that is reporting chronic fatigue among crews. The current schedule uses the four available teams (assumed to be 1 pilot and 1 sensor operator) to provide 24 hour coverage from a single location. A six days on, two days off cycle is used with teams working eight hour shifts.

Proposed Schedule

A revolutionary concept of operations (CONOP) will leverage the unique characteristics of UAS to decrease fatigue. MQ-1s typically operate using the Remote Split Operations (RSO) Beyond Line of Sight (BLOS) mode. BLOS requires the aircraft and earth terminal to be within the same satellite antenna radiation pattern or “footprint,” however RSO allows the Ground Control Station (GCS) to be geographically separated from the earth terminal while maintaining a connection through fiber optic networks (Whittle, 2016). In practice, MQ-1s are flown over Afghanistan via BLOS link to an earth terminal in Germany, which can be remotely accessed by a GCS in Nevada. The proposed CONOP will split the squadron into two smaller units, dispersed across a large time zone offset to eliminate the requirement for mid-shift, which is typically associated with Shift Work Disorder (expanded in next section). In this hypothetical scenario, GCSs would be installed at Royal Air Force (RAF) Base Lakenheath in the United Kingdom and Vandenberg Air Force Base (AFB), California. While a larger time offset could be achieved with Hickam AFB, having both bases outside the continental United States and therefore prolonged isolation from extended family, may lower morale and job satisfaction. The time zone map in Figure 1 can be used to establish time zone offsets.

Figure 1. World time zone map. The center line represents the internationally recognized location of Greenwich Mean Time (GMT), known as “Zulu Time” in military operations. Copyright 2016 by timetemperature.com.

At each base, crews will use a four on, two off schedule. The first three days will consist of a 12 hour flying shift, and the fourth will be a shorter non-combat day for training or administrative tasks as shown in Figure 2. At the end of a flying shift, crews perform an in-flight handover procedure per U.S. Air Force technical order 1MQ-1B-1 Aircrew Flight Manual, to transfer aircraft control to the other base. RSO allows the incoming crew to monitor the feed for a short period to gain familiarity, and other internet-protocol-based methods will be used to share mission products. Additionally, the time when the aircraft is on the ground for refueling, re-arming, and maintenance may overlap with a shift change, eliminating the need for an in-flight handover.

Figure 2. Proposed weekly schedule. Teams 1 and 2 are located at RAF Lakenheath, and Teams 3 and 4 are located at Vandenberg AFB.

As systemic aircrew shortages in the U.S. Air Force are remedied (Scotti, 2016), doubling of members in Teams 1-4 will allow the combat flying shifts to be reduced to six hours as shown in Figure 3, which can be expected to decrease the effects of fatigue and improve morale.

Figure 2. Proposed weekly schedule. Teams 1 and 2 are located at RAF Lakenheath, and Teams 3 and 4 are located at Vandenberg AFB.

Pros and Cons

The main focus of the dislocated crew schedule is to eliminate the performance, health, and quality of life decrements caused by extreme circadian rhythm shifts and work between roughly 10:00 PM and 8:00 AM local time, commonly know as mid-shift. Prolonged work on mid-shift commonly leads to Shift Work Disorder (SWD), characterized by extreme sleepiness and insomnia (Drake, 2010). Long-term effects include weight gain from metabolic changes, gastrointestinal problems, chronic high blood pressure, and mood/anxiety disorders from hormone imbalances. Second order effects include high risk of car accidents from falling asleep as seen in the medical, air traffic control, and law enforcement fields (Culpepper, 2010). The proposed schedule eliminates these risks by permanently placing workers on local day time schedules, which mitigates some of the downsides of long shifts (next paragraph). An additional benefit of this schedule is that it allows for a rest period that is equal to the period of fatigue and high stress associated with long shifts and combat operations respectively (Thompson, 2006), which can be expected to reduce professional “burnout.”

The 12-hour shifts are highly vulnerable to the effects of boredom, which occurs after as little as 20-35 minutes (Thompson, 2006). Monotonous flights, where high levels of vigilance are still expected, can also increased stress as perceived by the operator. A study of Hunter UAS operations by Barnes and Matz (1998) revealed significant performance degradation in eight hour flights, as compared to three hours, although participants reported that they liked the longer shifts because they facilitated higher target area awareness and continuity. An obvious con of the dispersed unit CONOP is the cost of installing GCSs at bases not already hosting UAS units, although further analysis is outside the scope of this paper.

Conclusion

This short essay has proposed a solution to chronic fatigue, stress, and quality of life issues in U.S. Air Force UAS units by dispersing crews across time zones, eliminating mid-shift, and adding rest periods of equal to combat flying shifts. The overall goal was to reduce professional burnout and reduce manning shortages through higher retention.

References

Barnes, M. and Matz, M. (2006). Crew Simulations for Unmanned Aerial Vehicle Applications: Sustained Effects, Shift Factors, Interface Issues, and Crew Size. Proceedings of the Human Factors and Ergonomics Society 42nd Annual Meeting.

Culpepper, L. (2010). The social and economic burden of shift-work disorder. Supplement to The Journal of Family Practice, 59(1).

Drake, T. (2010). The characterization and pathology of circadian rhythm sleep disorders. Supplement to The Journal of Family Practice, 59(1).

Scotti, C. (2016, September 19). The Air Force is facing a drone pilot shortage. Retrieved from http://www.businessinsider.com/air-force-facing-a-drone-pilot-shortage-2016-9

Thompson, W. (2006). Effects of Shift Work and Sustained Operations: Operator Performance in Remotely Piloted Aircraft(United States, U.S. Air Force, 311th Human Systems Wing). Brooks City Base, TX: USAF.

Whittle, Richard. Predator: The Secret Origins of the Drone Revolution. New York: Picador USA, 2015. Print.

UAS Beyond Line of Sight Operations (ASCI 638, 4.7)

Unmanned Aerial Systems (UAS) can be controlled via two main methods: line of sight (LOS) or Beyond Line of Sight (BLOS). In LOS operations, feedback (either through direct observation or wireless link) occurs along a vector between the ground control station (GCS) and vehicle. BLOS operations extend the range of the UAS through the addition of a relay between the GSC and vehicle. The following short essay will review the BLOS command and control (C2) scheme of the General Atomics RQ-1 Predator.

BLOS Infrastructure, Support, and Procedures

The RQ-1 can be operated over the horizon using two BLOS modes. Direct Ku-band satellite relay is accomplished when an earth terminal, either Trojan Spirit or Predator Primary Satellite Link (PPSL), is co-located with the GCS (Aftergood, 2002). This significantly extends the range of the aircraft and was first successfully used for target identification in Kosovo in 1997, although it is still constrained by requiring the aircraft and GCS to be within the satellite’s Ku antenna “footprint.” The second mode, Remote-Split Operations (RSO), allows the GCS to be geographically separated from the earth terminal, but connected with a fiber optic network. This was accomplished by decoupling the data stream multiplexing and radio frequency modulation functions, with the former staying in the GCS modem, and later moving “forward” to the earth terminal site (Whittle, 2015). This was first executed in 2002, with crews in Nevada flying RQ-1s over Afghanistan, relayed through a PPSL in Germany. The additional communications infrastructure for BLOS operations increases sustainment costs for the RQ-1. In one study, it was found that 82 personnel were required to support one Predator air patrol (Boyle, 2012). However, flight-hour costs are nearly an order of magnitude less then most other U.S. Air Force aircraft at $3,679/hour (Thompson, 2013), and the BLOS architecture costs are shared among numerous users. For either BLOS C2 mode, mission crews follow a lengthy checklist of procedures to gain or lose control of the aircraft from launch and recovery crews that fly the aircraft via line of site C2 from a GCS at the deployed site (Whittle, 2015). From a human factors perspective, control of the aircraft becomes more difficult in BLOS mode, as the distance and processing equipment add 1-2 second delays between pilot inputs and aircraft response. The cumbersome checklist procedures also increase the possibility of mistakes, in a GCS already known for poor usability, resulting in mishaps from partial control or improperly configured systems.

Figure 1. Diagram of Remote Split Operations (RSO) for RQ-1 Predator. Of note, the RQ-1 is only one of several users of the fiber optic network, earth terminal, satellite, and video network. Reprinted from USAF Capabilities briefing.

BLOS Advantages and Disadvantages

BLOS operations offer two primary advantages: extended range and distributed operations. Given satellites with appropriate transponder footprints, a long-endurance aircraft could potentially fly several thousand miles (satbeams.com), keeping the GCS away from potential hazards and requiring fewer launch and recovery locations. Distributed operations provides flexibility. For the RQ-1 case, if mission crews were unable to fly in Nevada due to a natural disaster, another suitably equipped base with access to the fiber optic network could assume those duties. Additionally, if weather was poor in Afghanistan, the same Nevada-based crew could potentially be used to fly an aircraft over Kosovo. BLOS operations can also be a disadvantage. The additional network nodes and communication pathways increase the vulnerability of the total system from a network security perspective (Martellini, 2013). In the most extreme case, a Denial of Service cyber attack could render a UAS completely ineffective, a worry that is absent from manned aircraft. 

Commercial BLOS Operations

The suitability of BLOS C2 for commercial operations is completely dependent on the mission, and whether that type of C2 would not be cost-prohibitive. BLOS would be appropriate for essentially any mission where flying extended-range UAS from one or few bases would be profitable. One example is BNSF Railway’s BLOS operation of Boeing-Insitu ScanEagles, which allows them to inspect thousands of miles of track from a single command center (Trimble, 2015). Other examples include agricultural survey, disaster response, and communications relay.

Conclusion

This short essay has researched the BLOS architecture for the RQ-1 Predator to understand the infrastructure, support, and procedures required for such a UAS. Benefits and shortfalls introduced with BLOS operations was also analyzed, along with applicability to commercial ventures. As with nearly any technology, propagation of BLOS UAS will depend on their ability to add value to the mission.

References

Aftergood, Steven. (2002). RQ-1 Predator MAE UAV. Retrieved from https://fas.org/irp/program/collect/predator.htm

Boyle, Ashley. (2012). The US and its UAVs: A Cost-Benefit Analysis. Retrieved from http://www.americansecurityproject.org/the-us-and-its-uavs-a-cost-benefit-analysis/

Martellini, M. (2013). Cyber security: Deterrance and IT protection for critical infrastructures. Cham: Springer.

Thompson, Mark. (2013). Costly Flight Hours. Retrieved from http://nation.time.com/2013/04/02/costly-flight-hours/

Trimble, Stephan. (2015). FAA approves beyond line of sight, urban UAV flights. Retrieved from https://www.flightglobal.com/news/articles/auvsi-faa-approves-beyond-line-of-sight-urban-uav-412021/

SatBeams SPRL. (2016). World of Satellites at Your Fingertips. Retrieved from http://www.satbeams.com/

Whittle, Richard. Predator: The Secret Origins of the Drone Revolution. New York: Picador USA, 2015. Print.

UAS Integration in the NAS (ASCI 638, 3.6)

The quantity and frequency of Unmanned Aerial Systems (UAS) use is growing across the United States as more markets realize the many benefits, such as low cost, endurance, or human safety. Since 2012, the Federal Aviation Administration (FAA) has been modernizing the National Airspace System (NAS) under the Next Generation Air Transportation System (NextGen) initiative, which is expected to be complete by 2025. The following essay reviews NextGen as it applies to UAS and their human factors.

NextGen Goals and Improvements

NextGen has the overarching goals of increasing safety, efficiency and sustainability through collaboration and technology application. The Global Positioning System (GPS), and voice and data communication networks form the backbone of the new system. NextGen is truly a “system of systems,” with four focus areas (FAA, 2017). Automation includes a suite of applications for data sharing between dispatchers, crews, and controllers that support real-time collaboration and decision-making to efficiently work through the dynamic aviation environment. Enterprise Information Management is the network architecture beneath the user and automation layers that ensures data is reliably disseminated in a common language. Communication focuses on replacing 12 antiquated ground systems with a common internet-protocol-based system. Additionally, digital datalinks will be used to send flight plans and clearances, significantly reducing line-of-sight radio communication. Lastly, Surveillance seeks to replace traditional wide area radar tracking with Automatic Dependent Surveillance-Broadcast (ADS-B). ADS-B “out” will replace traditional Mode 3 transponders and transmit GPS position, velocity, and other data. ADS-B “in” users will be able to receive traffic, weather, and advisory data from FAA ground stations. Overall, these four focus areas will guide improvement to the NAS that is forecasted to save airlines and the FAA over $11 billion in operating costs and avoid over $22 billion in economic losses (FAA, 2015).

UAS integration with NextGen

The Next Generation Air Transportation System Joint Planning and Development Office (JPDO, 2012) has published a roadmap outlining the activities needed for full integration by 2030. UAS are poised for NextGen integration, since they are inherently a digital system that already generates much of the data needed by automation, communication, or surveillance functions. The MITRE Corporation has investigated the “communications” and “airspace operations” challenges further and highlighted the need for interoperability standards, recommending STANAG 4586 due to its already wide-spread use, along with an example airspace clearance process (Paczan, Cooper, Zakrzewski, 2012). Specifications for hardware integration will likely be driven by the size, range, and mission of the UAS. One question that affects all is where the UAS (which includes the vehicle, control station, and operator) will interface with NextGen: at the vehicle, ground control station (GCS), or a combination of the two. An airborne vehicle can extend the communication range of an un-networked GCS, although a networked GCS can have near infinite range. The solution will need to be a function of GCS mobility, onboard, communication capability, and lost-link logic. One of the most challenging aspects of UAS integration is satisfying sense-and-avoid (SAA) requirements. Marshall, Barnhart, Shappee, and Most (2016) explore the various hardware options, ranging from stereo optical sensors to radar, although the largest challenge may be changing FAA culture. Aircraft certification has historically been based on satisfying equipage mandates or system tolerances, however this may not be appropriate for the wide range of UAS. For example, an SAA radar requirement would ensure that small UAS would never be able to comply. Instead, requirements need to be levied as a desired end-state, such as detecting and avoiding intruding traffic with a given time margin and slant range separation.

Human Factors Considerations

Human factors considerations for UAS integration with NextGen need to cover both the GCS and air traffic controller consoles. With full implementation of the system in 2025, pilots/operators and controllers will need properly designed displays to process, filter, and correlate the tremendous amount of data. Of note, the JPDO integration roadmap specifically calls for research in human-automation interaction, with an emphasis on creating pilot-centric GCSs, an area which has historically been deficient. The wide range of pilotless vehicles and missions will again drive the need for goal versus tolerance-oriented certification standards. Paczan, Cooper, Zakrzewski (2012) proposed standardized clearance instructions that would be recognized and displayed by all GCSs, such as a two-minute instrument hold at the next waypoint in the mission.

Conclusion

This short essay has conducted a review of the available literature on UAS integration with NextGen, as they will need to be by 2025. The overall system was studied to gain an understanding for UAS and their associated human factors, while gaining appreciation for the wide range of challenges that required detailed analysis.

References

Federal Aviation Administration. (2017, January 12). Next Generation Air Transportation System (NextGen). Retrieved from https://www.faa.gov/nextgen/

Federal Aviation Administration. (2015). NextGen Works for Airlines. Retrieved from https://www.faa.gov/nextgen/library/media/getSmart_airlines.pdf

Marshall, D. M., Barnhart, R. K., Shappee, E., & Most, M. (2016). Introduction to unmanned aircraft systems. Boca Raton: Taylor & Francis, CRC Press.

Next Generation Air Transportation System Joint Planning and Development Office. (2012). NextGen UAS Research, Development and Demonstration Roadmap. Retrieved from https://fas.org/irp/program/collect/uas-nextgen.pdf

Paczan, N., Cooper, J., & Zakrzewski, E. (2012). Integrating UAS in NextGen Automation Systems. Retrieved from https://www.mitre.org/sites/default/files/pdf/12_3347.pdf

UAS GCS Human Factors Issues (ASCI 638, 2.6)

Designing Unmanned Aerial Systems (UAS) Ground Control Stations (GCS) that replicate the sensory cues of manned aircraft is challenging, especially for small vehicles (Department of Defense Group 1-3) that return limited streams of telemetry data. A compilation of accident studies by Marshall, Barnhart, Shappee, and Most (2016) highlights that 32-69% of events involved human factors. While analysis varied by study, a clear theme emerged that improvements to the human-machine interface could mitigate training shortfalls, poor decision making, and perception errors. The following paper investigates the Optimum Solutions Transportable Ground Station from a human factors perspective.

Functional Analysis

The Transportable Ground Station (TGS) is a portable UAS GCS that provides mission management, command & control (C2), and sensor feedback, in a 70lb Pelican-style case with self-contained power supply (Optimum Solutions, 2016). Mission management is enabled by a laptop computer driving two monitors that are configurable for planning, telemetry, or data exploitation displays. The default planning software is Piccolo Command Center (PCC), due to the popularity of the Piccolo family of small autopilots, although any Windows-compatible third party software can be installed. PCC is used to create missions for autonomous flight path execution, terrain awareness, and perform simulations.

        

Figure 1. Optimum Solutions Transportable Ground Station (TGS) overview (left) and payload control stick detail (right). Copyright Optimum Solutions, 2016.

TGS C2 capabilities are facilitated by L, S, or C-band datalinks with several common physical interfaces available for reconfiguration in the field. TGS transmits uplinks with standard Frequency Modulation (FM), or Coded Orthogonal Frequency Division Multiplexing (COFDM), which has superior resistance to interference and multi-path effects (Keithley Instruments, 2008). Telemetry is downlinked from the vehicle, processed by PCC and displayed on horizontal map, pseudo “heads-up”, or numeric tables in the Windows interface. PCC enables updates to autonomous flight paths and the operator can make manual inputs via the trainer interface on Futaba remote controls. Payload C2 is designed primarily for video sensors, with separate joysticks and monitors providing payload command and feedback respectively (Figure 1, right). 

Negative Human Factors Issues and Solutions

Two negative human factors deficiencies were identified on the TGS. On the pilot side, there are no means to build situational awareness of the vehicle’s immediate surroundings. Several stand-alone systems are available, however a solution should be consistent with the all-in-one theme of the TGS. FlightAware has teamed up with the Raspberry Pi community to exploit Automatic Dependent Surveillance-Broadcast (ADS-B) signals for less then $100 (FlightAware, 2016). The FlightAware Pro Stick software-defined radio is used inline with a compatible antenna and Raspberry Pi project computer to feed the PiAware desktop application. This provides pilots with real-time air traffic and weather data from stations within 200-300 miles on one of the two TGS mission planning monitors. The open Raspberry Pi architecture could also be used to export the data stream to the mission planning application for fusion with aircraft telemetry, increasing the crew’s SA.

On the payload side, the independent sensor joystick has a poor ergonomic effect on the operator. The portable nature of TGS means that the operator may not have the benefit of a seat conveniently aligned with the stick, which could lead to arm discomfort and tracking errors if the TGS is not positioned at their approximate elbow height (Human Solutions, 2017). Additionally, the payload function buttons are located directly aft of the stick in a likely forearm resting location, so that an operator needs to move one arm to make function inputs with the other, possibly inducing undesired payload movements. Lastly, the TGS may be located outside, where solar glare will likely degrade the operator’s perception of the picture, causing suboptimal settings to be applied. These deficiencies could be eliminated by replacing the fixed joystick and monitors with a video-game-style hand controller and first person view (FPV) goggles. For example, the SQDeal gaming controller with wired serial interface is infinitely adjustable in position with the same number of function buttons, and Fat Shark Dominator v3 goggles would provide a truer display for applying the proper sensor settings.

Conclusion

This short essay investigated the Optimum Solutions TGS UAS control station and revealed two human factors deficiencies. The first involved crew SA of vehicle environment and the second highlighted ergonomic problems with the sensor operator interface. The proposed solutions were installation of an open-standard ADS-B receiver and software, gaming controller, and FPV goggles.

References

FlightAware. (2016). Pro Stick and Pro Stick Plus - FlightAware's USB ADS-B and MLAT receiver ✈ FlightAware. Retrieved from http://flightaware.com/adsb/prostick/

Human Solutions. (2017). Calculate the ideal height for your ergonomic desk, chair and keyboard. Retrieved from http://www.thehumansolution.com/ergonomic-office-desk-chair-keyboard-height-calculator.html

Keithley Instruments, Inc. (2008). An Introduction to Orthogonal Frequency Division Multiplex Technology. Retrieved from http://www.ieee.li/pdf/viewgraphs/introduction_to_orthogonal_frequency_division_multiplex.pdf

Marshall, D. M., Barnhart, R. K., Shappee, E., & Most, M. (2016). Introduction to unmanned aircraft systems. Retrieved from http://site.ebrary.com.ezproxy.libproxy.db.erau.edu/lib/erau/detail.action?docID=10508871

Optimum Solutions. (2016). Transportable UAV GROUND STATION. Retrieved from http://www.optimumsolution.com/item16.html