Activity 4.6 Research: UAS Beyond Line of Sight Operations

Activity 4.6- Research: UAS Beyond Line of Sight Operations

Joseph Younts

Embry Riddle Aeronautical University Worldwide

ASCI 638: Shawn Wynn

April 2017

  

UAS Beyond Line of Sight Operations

            The Global Hawk is a high altitude, long endurance (HALE) unmanned aerial vehicle (UAV) designed to collect reconnaissance information. The Global Hawk is used to collect extended reconnaissance which is responsive and sustained data that can be gathered and set back to the operator from anywhere in enemy territory on any given day, regardless of the weather (Pike, n.d.). The Global Hawk can operate at ranges up to 11,000 nautical miles from its home base and fly at altitudes greater than 60,000 feet for over 24 hours at a time (Gibbs, 2015). The Global Hawk has been outfitted with many technologies that make high altitude reconnaissance possible. The Global Hawk carries electro-optical technology, infrared sensors, and synthetic aperture radar and can be flown via line of sight (LOS) operations or beyond line of sight (BLOS) operations (Pike, n.d.). Line of sight operations are possible through the use of data link communications while beyond line of sight operations require the use of Ku-band SATCOM data links for command, control, and communication with the Global Hawk.

            The Global Hawk can be flown all over the world and is not restricted to LOS operations. In order to operate outside normal LOS operations, the Global Hawk was designed to use Ku-Band satellite connections to fly beyond the line of sight. SATCOM systems utilize satellites to allow the Global Hawk operator to use voice and data telecommunications. SATCOM can use geo-stationary or low-Earth orbits to control voice and data telecommunications (Duncan Aviation, 2015). SATCOM has several different parts ranging from space components to ground stations. “The space segment consists of the orbiting satellites and the ground segment is made up of control stations that maintain the satellites’ health in orbit and gateways that provide the interconnecting link to the groundbased telecommunications networks” (Duncan Aviation, 2012, pg. 3).

            The infrastructure for the Global Hawk is relatively simple. The system is made up of the Global Hawk, the payload on the aircraft, a ground control station and mission planning system, and data links that allow the Global Hawk to operate (Northrop Grumman, 2012). The Global Hawk has the ability to take off and land autonomously and can also be put into an autonomous flight mode during cruise settings thanks to a sophisticated mission and flight management system. Due to these autonomous abilities and advances in technology, the crew required to fly the Global Hawk is much smaller than the number of crew members required for other UAS. A smaller crew also means that the crew can provide more on station time than a larger crew required to support a manned aircraft platform (Northrop Grumman, 2012). The mission control element (MCE) is used to provide management of the Global Hawk and its sensors. The MCE controls the aircraft, any data links to the Global Hawk, and payloads being carried. Thanks to the MCE, the Global Hawk can transmit near real time information to operators and commanders at a moment’s notice anywhere in the world. Within the MCE, the crew conducts C3 operations (command, control, and communications), mission planning, and image quality control (Northrop Grumman, 2012).

            The Global Hawk has several support systems that help to safely execute missions. The systems on board the Global Hawk are similar to the support systems on manned aircraft. Processes and management systems used by supplies and maintenance are the same as manned aircraft, but the manuals for the Global Hawk are electronic and have virtual illustrations (Northrop Grumman, 2012). The crew chief has an important role to play during missions. The crew chief is responsible for connecting a vehicle test computer to the aircraft to monitor all systems and components during flight. Another laptop used during missions contains all maintenance manuals needed to troubleshoot any problems (Northrop Grumman, 2012).

            The Global Hawk can effectively operate within visual line of sight of the operator for short missions and beyond visual line of sight for long range, long endurance reconnaissance missions anywhere in the world. BLOS operations are critical because it allows the operator to provide intelligence to soldiers on the ground in near real time. BLOS operations require Ku SATCOM communications with satellites in space while LOS operations simply require the Global Hawk to operate within predefined range for the duration of the flight to maintain line of sight connectivity (Northrop Grumman, 2012). The advantages to BLOS operations include long range flights across the world, long endurance flights that provide critical reconnaissance data to commanders, and rotation of operators to reduce fatigue. The disadvantage to BLOS operations is that collection of data may take long amounts of time due to long range flights. There could also be a delay on transmission of data when the Global Hawk is thousands of miles away from the GCS. BLOS operations would also require each component of the UAV to be working correctly in order for the operator to provide necessary reconnaissance data. During BLOS flight, if the operator needs to put the UAV into manual control mode, a delay on the input of the flight controls could be hazardous to the safety of the flight. Line of sight operations will have higher transmission speeds and in the event of an emergency, it is likely that the operator will be able to land the UAV safely at the home airbase. With LOS operations being much closer to the GCS, there are fewer chances that interference can occur to interrupt the signals between the GCS and the Global Hawk.

            The transition between LOS and BLOS can present several human factors issues. When BLOS operations have been initiated, SATCOM data links have been susceptible to latency issues. Latencies between the GCS and the Global Hawk can make remote piloting become a less feasible option. When remote piloting is no longer an option, autopilots must be turned on because of latencies experienced during BLOS operations (Valavanis, Oh, & Peigl, 2008). Since the Global Hawk is a long endurance UAV, the operator may need to fly the UAV across multiple ATC regions. One ATC procedure for UAS flight across multiple ATC regions is to use the UAV as a communication relay. The relay will allow a ground operator to stay in contact with ATC constantly within specific regions of airspace (Valavanis et al., 2008). If ATC contact with the operator is lost, the ground control station will attempt to re-establish the data link between the GCS and ATC. When the Global Hawk is flying BLOS, the only way to re-establish the data link between the GCS and ATC is by carrying multiple VHF transceivers and having redundant voice communication systems on board (Valavanis et al., 2008). There is a chance that the operator could completely lose contact with ATC, putting the Global Hawk and other aircraft at risk for a midair crash. Another issue when switching between LOS and BLOS could be situational awareness. The final human factor issue that could become a problem is the handoff of the Global Hawk from one GCS to another. If the UAV is handed off to another GCS, situational awareness levels for the receiving operator could be reduced due to flight mode inputs by the previous operator. Checklists for switching between operators should be followed to ensure there is a smooth transition from one GCS to another. The operator handing the UAV off should ensure that aircraft settings and configurations are set in a standard position to prevent the next operator from turning off any critical functions on the UAV.

            According to Northrop Grumman (2012), the Global Hawk is the only UAS to receive both military and NASA airworthiness certificates. In order to receive the airworthiness certificate, the Air Force put the Global Hawk through more than 600 airworthiness test criteria. Each component was tested to meet extreme specification requirements and the Air Force had to verify that each system was safety during all phases of flight (Northrop Grumman, 2012). When the RQ-4 Global Hawk received the airworthiness certificate, the Air Force stated that the Global Hawk would be able to fly safely within the National Airspace System (NAS). The first challenge that will be faced for BLOS operations within the NAS will be regulations that must be developed by the FAA. Amazon is only one business out of many that have plans to use UAVs to deliver packages to customers within a certain distance from shipping warehouses. If Amazon could perform BLOS operations, there would be less congestion on roads which would reduce carbon emissions from vehicles. BLOS operations would be greatly utilized by search and rescue teams, cargo transport services such as Amazon or UPS, crop dusting and agriculture operations, and even natural disaster teams conducting research on damages. These commercial operations are in the near future, especially considering the rapid growth of UAS in the United States and due to the FAA’s roadmap for integration of UAS into the NAS. However, until new regulations are developed and detect, sense and avoid technology is created, commercial operations will continue to be hindered within the United States.  

References

Duncan Aviation. (2012). Straight Talk About Satcom & HSD. Retrieved from             https://www.duncanaviation.aero/files/straight-talk/Straight_Talk-Satcom_HSD.pdf

Gibbs, Y. (2015, March 11). Global Hawk - Performance and Specifications. Retrieved from             https://www.nasa.gov/centers/armstrong/aircraft/GlobalHawk/performance.html

Northrop Grumman . (2012). Q-4 Enterprise [Brochure]. Author.

Pike , J. (n.d.). RQ-4A Global Hawk (Tier II HAE UAV). Retrieved from             https://fas.org/irp/program/collect/global_hawk.htm

Valavanis, K., Oh, P., & Piegl, L. (2008). Unmanned Aircraft Systems International Symposium on Unmanned Aerial Vehicles, Uav-08. Springer Verlag.

Activity 3.4 Research: UAS Integration in the NAS

UAS Integration in the NAS

            Radar systems have long been used in the United States to safety control the movements of aircraft within the National Airspace System (NAS). However, with air traffic increasing in the NAS, the FAA has deemed it necessary to continue development of the Next Generation Air Traffic System (NextGen). NextGen has been in the works for many years, but as time passes, the potential benefits of NextGen continue to push the FAA to finish this new system. NextGen is not a single system; it is made of a series of initiatives that will make the NAS more efficient and safe (Houston, 2016). NextGen was formed in 2000 and officially started in December of 2003. NextGen was designed to be a multi-agency, multi-year modernization of the current, outdated air traffic system (Houston, 2016). The NextGen air traffic system has many benefits. These benefits include better travel experiences, fuel savings for operators, a reduction in emissions due to more direct routes, reduced separation between aircraft due to more accurate systems, reduced congestion, better communications across the NAS, easy access to in flight weather information, and improvements for on board technology (Houston, 2016).

            Automatic Dependent Surveillance-Broadcast (ADS-B) is a critical component of the NextGen system. ADS-B will affect all segments of aviation. ADS-B will allow pilots and air traffic control to review real time information regarding the airspeeds, headings, altitudes, and other information of various aircraft equipped with ADS-B. With ADS-B, pilots and air traffic control will receive continuous updates from air traffic, allowing pilots and ATC to have unprecedented amounts of situational awareness (NextGen, 2016). With real time updates on other aircraft, both commercial aviation and general aviation will become safer. ADS-B for general aviation will provide pilots with traffic updates, in flight weather information, and access to flight information services. The national airspace system (NAS) is experiencing growth at a rapid rate; ADS-B will increase safety and airspace efficiency for aircraft flying within the national airspace system and for aircraft flying into controlled airspaces. ADS-B will improve safety on the ground and in the air. This technology will also reduce costs for operators due to more direct routing and will also reduce harmful effects on the environment (NextGen, 2016).

            UAS integration into the NAS is already beginning. UAS have become a large part of military and government operations, ranging from the Department of Defense and Homeland Security to all branches of the military for surveillance and bombing missions. UAS are also becoming popular for non-military operations. These operations include border patrol, search and rescue operations, flooding impact studies, and even for erosion and crop damage control (Paczan et al., 2012). Currently, UAS are not to be flown for commercial operations, but UAS operators can operate under a Certificate of Waiver or Authorization. In 2011 Customs and Border Protection utilized the surveillance abilities of the MQ-9 Predator-B to seize more than 7,600 pounds of illegal narcotics (Paczan et al., 2012).

            UAS within the NAS will require special considerations based on data communications and enhanced automation systems. With the NextGen system, there will be enhancements to the two way data communication links shared between aircraft and ATC. Data communications have been designed to provide pilots and ATC with routine and strategic information that will impact the various phases of flight (Paczan, Cooper, & Zakrzewski, 2012). Benefits to data communications include greater amounts of information displayed for pilots in the cockpit, new sophisticated automation tools, smarter, more efficient coordination between ATC and pilots, and less congestion on ATC frequencies (Paczan et al., 2012). Automation systems will streamline operations between ATC and pilots. Automation systems will be critical to the safety of UAS within the NAS because controller workload will increase as the ratio of UAS to manned aircraft increases (Paczan et al., 2012).

            UAS integration into the NAS will face several challenges. Detect, sense, and avoid technology is still rather new, but with ADS-B becoming a requirement for manned aircraft by 2020, ADS-B has been identified as a solution for UAS within the NAS. The limitation for ADS-B usage is that any non-participating aircraft flying within the NAS will not be seen by other aircraft equipped with ADS-B. If UAS are required to have ADS-B, other operators and ATC will have more control over the safety of the NAS. Another challenge for integration of UAS into the NAS will be based around flight plans. Flight plans are an integral component of air traffic operations within the NAS (Paczan et al., 2012). Flight plans allow controllers to safely and effectively manage the various classes of airspace within the NAS. When UAS are being integrated into the NAS, specific contingency routes must be considered before flight. In the event of an emergency, where should a UAV operator fly the unmanned aircraft? Contingency routes are normally pre-programmed into the flight computers on the aircraft, but with unmanned aircraft, there could be hundreds of specific contingency routes. Paczan et al., (2012) suggest having a storage mechanism in place to maintain all contingency routes for a UAV. These routes would have to carry specific activation conditions in the event of an emergency.

            There are other human factors considerations that must be researched before UAS can be integrated into the NAS. This author believes complacency and lack of awareness will be human factors that may play a role in future UAS accidents. Complacency occurs when routine activities become habitual; tasks that are repeated on a daily basis become “easy” and therefore the operator will use muscle memory to fly the UAV. Simple flight routes that are flown repeatedly will cause the operator to become relaxed rather than being alert (The Human Factors, n.d.). Complacency can also occur after a near miss or recovery from a potential disaster. The relief that will be felt by an operator after a potential accident can result in a state of relaxation and reduced situational awareness (The Human Factors, n.d.). In addition to potential accidents, too little pressure can also cause complacency. Too much stress causes fatigue, but too little stress causes complacency. Therefore, some stress can actually be beneficial to the operations of UAV operators.

            Lack of awareness is also a potential hazard to UAV integration into the NAS. “Working in isolation and only considering one’s own responsibilities can lead to tunnel vision; a partial view, and a lack of awareness of the affect our actions can have on other and the wider task” (The Human Factor, n.d., para. 29). Lack of awareness can lead to unnecessary stressors, an increase in the levels of fatigue, and loss of situational awareness, increasing the chances for an accident. While ADS-B will increase awareness for manned aircraft, unless UAVs within the NAS are required to have ADS-B, UAV operators will not be as aware as they should be. ADS-B will also only allow operators to sense other aircraft with ADS-B technology. Unless there is a mandate to have ADS-B on UAVs, non-participating aircraft will be a threat to other manned and unmanned aircraft in the NAS.

            In conclusion, UAVs and NextGen technologies can be integrated to create a more safe and efficient airspace system for UAV usage. UAV operations will continue to grow in the United States, and with this in mind, the FAA must continue to consider how to safely integrate UAVs into the NAS. With ADS-B technology, UAVs should be able to operate within a section of airspace dedicated to for UAVs. However, even with NextGen technology, the FAA must consider what regulations should be developed in order to ensure UAVs have detect, sense, and avoid technology, particularly for commercial operations.

References

Houston, S. (2016, August 14). NextGen in a Nutshell: The Next Generation Air Traffic System. Retrieved from https://www.thebalance.com/nextgen-in-a-nutshell-282561

N. M. Paczan, J. Cooper and E. Zakrzewski, "Integrating unmanned aircraft into NextGen            automation systems," 2012 IEEE/AIAA 31st Digital Avionics Systems Conference (DASC), 

Williamsburg, VA, 2012, pp. 8C3-1-8C3-9. doi: 10.1109/DASC.2012.6382440

Next Generation Air Transportation System (NextGen). (2016, October 26). Retrieved from             https://www.faa.gov/nextgen/programs/adsb/

The Human Factors "Dirty Dozen". (n.d.). Retrieved from             http://www.skybrary.aero/index.php/The_Human_Factors_%22Dirty_Dozen%22