UAS Integration in the NAS ASCI 638 - 3.6

 

Figure 1. UAS in the NAS (Cameron, 2012)

“NextGen is the FAA-led modernization of our nation’s air transportation system” (What is NextGen, 2017).  The goal is to increase safety and efficiency in the national airspace. Replacing ground based navaids, such as an NDB or VOR, with GPS based airways. Radar would be replaced with Satellite GPS tracking and Automatic Dependent Surveillance-Broadcast (ADS-B) of aircraft for ATC. These combined will enable aircraft to fly closer together, yet still safely, since the location is more accurate and up to date compared to radar. More direct routes are able to be taken with GPS than ground based navaids which decreases fuel consumption, brings down the overall cost of the trip and reduces transportation time (What is NextGen, 2017).  

ATC needs to be able to communicate with the UAS controller whenever the UAS is in controlled airspace.  Since the UAS controller is on the ground, and most likely not in line-of-sight communication with ATC the UAS could be used to relay the communication to the ground controller via satellite communications (Pongracz & Palik, 2012).  This would allow direct communication with the UAS controller and it would be similar to contacting an onboard pilot. Of course, this only works for larger UASs, most notable military controlled UASs that have access to satellite communications.  An example would be the Global Hawk that uses Satcom to relay UHF/VHF communication between ATC and the ground controller (Global Hawk UAS, 2018).

According to the Federal Aviation Regulation (FAR) 14CFR 91.111(b) “the operator of an aircraft must maintain vigilance so as to see and avoid other aircraft. The operator must also give way to other aircraft if they have the right of way”.  Since a UAS cannot see to avoid it needs to “sense and avoid”.  ADS-B is used to broadcast to ATC the position, altitude and velocity of an aircraft. Having ADS-B built into a UAS would enable ATC to locate the UAS, any aircraft or person with an ADS-B receiver and let the UAS know of other aircraft in its vicinity and it could navigate to stay clear of the manned aircraft. A company called UASioni has released a line of small ADS-Bs that could easily be fitted into a small UAS, some of these are only an inch by an inch in size (ADS-B Transceivers, n.d.).  

PrecisionHawk has developed Low Altitude Tracking and Avoidance System, or LATAS. LATAS is “onboard system that provides flight planning, tracking and avoidance for every drone in the sky using real-time flight data transmission based on existing world-wide cellular networks” (Say Hello, 2015).  LATAS uses existing cell towers to transmit a UASs location to ATC, which would relay that position to pilots in the area. This is a small bit of electronics, about one inch by two inches, that can be added to any UAS during manufacturing.

NextGen will need to address human factors the same way the previous National Airspace system (OldGen? Maybe PreviousGen?) needed to. We will still have crew rest, human inattention, human mistakes, a need for well designed human machine interface and crew resource management just to name a few. With the advent of ADS-B receivers there has been an advancement in safety. Previously a pilot needed to be visually scanning outside the cockpit when flying VFR, and even IFR at times if not in the clouds, in order to see-and-avoid other aircraft. While this is still a necessity the use of ADS-B has enabled pilots to be able to see other aircraft relative to their position on a moving map or digital display in today’s glass cockpits. If a UAS had an ADS-B transmitting it location even a small hard to visually see UAS will be prominently displayed on a screen for other pilots in the area.

When we fully upgrade to NextGen, or if everyone starts using ADS-B while still fying ground based navaids human factors will always be an issue. We need to continue to train, improve and stay vigilant as members of the aviation industry. As with all aviation it takes skilled people, on the ground, in the tower or in the sky to make it all work safely. 

  

References

ADS-B Transceivers, Receivers and Navigation Systems for Drones (n.d.). Retrieved January 28, 2018 from http://www.unmannedsystemstechnology.com/company/UASionix-corporation/

Cameron, A. (2012, May 22). The System: Fly the Pilotless Skies: UAS and UAV. Retrieved January 28, 2018, from http://gpsworld.com/the-system-fly-the-pilotless-skies-uas-and-uav/

Say Hello to LATAS (January 09, 2015). Retrieved January 28, 2018 from http://www.precisionhawk.com/media/topic/say-hello-to-latas/

Global Hawk UAS of NASA. (2018). Retrieved January 28, 2018, from https://directory.eoportal.org/web/eoportal/airborne-sensors/content/-/article/global-hawk

What is NextGen? (2017, November 21). Retrieved January 28, 2018, from https://www.faa.gov/nextgen/what_is_nextgen/

UAS GCS Human Factors Issue ASCI 638 - 2.6

Predator RQ-1

The RQ-1 Predator is a long-endurance, medium-altitude UAS for surveillance and reconnaissance missions and interdiction. Imagery is provided from synthetic aperture radar, video cameras and a forward-looking infrared (FLIR) can be sent real-time to the front-line soldier, operational commandeer or worldwide via satellite communications. It can be armed with AGM-114 Hellfire missiles.  The ground control station (GCS) is a single 30 foot trailer, containing pilot and payload operator consoles, three Boeing data exploitation and mission planning consoles and two synthetic aperture rater workstations. It is launched with direct line-of-sight control from a semi-improved surface. Line-of-sight data link or satellite links produce continuous video for the operators and all controls are commanded through those communication channels (Predator RQ-1, n.d.).

One human factors issues that lead to an accident was the design of a control lever made it easy to create a mishap. The GCS has two operators who sit at identical consoles. One operator is the pilot and the other is the payload operator. When configured for the pilot the condition lever will start or stop fuel flow and can feather the propeller to reduce drag. When configured for the payload operator the same condition lever will operate the iris on the camera. Per the checklist if control is transferred from one console to the other the condition lever on the payload console must be set to match the pilot console prior to transfer of controls. During a control transfer the checklist was not followed and the condition lever was not matched. Once the transfer of controls was completed the conditions lever which had been set to control the iris was not set to stop fuel flow to the engine, causing the engine to shut down. This was a major contributing factor to a Predator crash in 2016 in Arizona (Carrigan, Long, Cumming & Duffner, n.d.)

This failure mode could be designed out of the system. Something as simple as having two distinct condition levers, one for the iris control and a separate for engine control.  Another would be to prevent or give a warning if pilot control transfer is attempted and the condition lever is not matched between the two control consoles (Carrigan, Long, Cumming & Duffner, n.d.). “While some would advocate for more training to address this problem, humans are imperfect systems, and it is important to design for an operator that may make mistakes” (Carrigan, Long, Cumming & Duffner, n.d.).

Human factors in cockpit design occurs both in unmanned and manned aircraft systems. The cockpit needs to be designed in such as way as to allow the pilot to be efficient and comfortable as possible.  “One of the first formal human factors studies was carried out by Fitts and Jones in 1947 to analyze pilot experiences with display readings” (Flying Towards the Future).  In the late 1970s cockpits had an excess of 100 individual components the pilots were required to monitor and manage, the technology at the time only allowed for a gauge to display one piece of information (Salas, E., Maurino, 2010).

Another human factors issue is the limited field of view for the Predator operator. The original design of the GCS gave approximately a 30-degree field of view from the nose camera. It was stated that it is similar to “driving your care with paper towel tubes over your eyes” (Shiner, 2001). This is shown on one screen for the pilot overlayed with information such as transponder code, airspeed and

Original GCS Cockpit   (It's Better to Share, 2011)

altitude. A second screen providing data such as a map with a symbol of the aircraft and the corridor for its’ route of flight. This limited field of view, and the lack of vestibular and proprioceptive cues, means the pilots rely on visual cues to fly, such as when the runway fills the bottom third of the screen the nose is raised to flare prior to touchdown.

Raytheon designed a new cockpit for the GCS that now has three wide screens and a 270-degree field of view with some synthetic data overlayed. This allows for a large increase in the pilot’s situational awareness. This improved display along with more ergonomic controls, more comfortable

Advanced GCS (Pocock, 2007)

and adjustable seat as well as new interfaces increases the comfort of the pilot as well as their situational awareness (Pocock, 2007).

Limited field of view can occur with manned aircraft as well.  Many military and civilian pilots fly at night under Night Vision Devices (NVD) such as night vision goggles. These goggles limit the field of view to around 40-degrees. The pilot overcomes this limitation by increasing scan rate, looking left and right frequently and not relying on peripheral vision in order to see surroundings.

References

Carrigan, G., Long, D., Cummings, M., & Duffner, J. (n.d.). Human Factors Analysis of Predator B Crash [Scholarly project]. Retrieved January 21, 2018, from https://hal.pratt.duke.edu/sites/hal.pratt.duke.edu/files/u13/Human%20Factors%20Analysis%20of%20Predator%20B%20Crash%20.pdf

Flying Towards the Future: An Overview of Cockpit Technologies (October, 2013). Retrieved January 21, 2018 from http://www.ergonomics.org.uk/flying-towards-the-future/ 

Its Better to Share: Breaking Down UAV GCS Barriers. (2011, October 03). Retrieved January 21, 2018, from https://www.defenseindustrydaily.com/uav-ground-control-solutions-06175/

Pocock, C. (2007, June 16). New UAV Control System May Cut Predator Losses. Retrieved January 21, 2018, from https://www.ainonline.com/aviation-news/defense/2007-06-16/new-uav-control-system-may-cut-predator-losses

Predator RQ-1 / MQ-1 / MQ-9 Reaper UAV. (n.d.). Retrieved January 21, 2018, from http://www.airforce-technology.com/projects/predator-uav/

Salas, E., Maurino, D. E. (2010). Human factors in aviation (2nd ed.). Amsterdam: Academic

            Press/Elsevier

Shiner, L. (2001, April 30). Predator: First Watch. Retrieved January 21, 2018, from https://www.airspacemag.com/military-aviation/predator-first-watch-2096836/?all