Monitoring UAS in the National Airpsace System (NAS)

How can the separation of unmanned aircraft be monitored and maintained (among other unmanned aircraft and manned aircraft) in the National Airspace System (NAS)? What considerations need to be made for varying sizes (i.e., Group 1 to 5) and airframes of UAS (e.g., fixed-wing, rotary-wing, and lighter than air)? What technology is currently employed by manned aircraft and is it adaptable for use with unmanned? How can the separation of unmanned aircraft be monitored and maintained (among other unmanned aircraft and manned aircraft) in the National Airspace System (NAS)? This is a question still being asked, and unmanned aircraft developers are continuing to evaluate the feasibility of integration (Embry Riddle Aeronautical University, 2014). Communications between the ground control station (GCS) and the unmanned aircraft in the air alone is complex enough – a typical UAS communication system is composed of an antenna, transmitter, receiver, transceiver, and a multiplexer. A typical communications exchange consists of an uplink (UAV control) and downlink (UAV status) – the downlink is typically comprised of the following sections – header, inertial measurement unit (IMU) readings, flight control values, power, warnings, communications, payload, GPS and sense and avoid (Embry Riddle Aeronautical University, 2014). A great deal of the communications system on board and on the ground of a UAS is dedicated solely to the communication between the GCS and the UAV; as mentioned in the introduction, UAV developers are still looking at the feasibility of integration into the National Airspace System. The Department of Defense (DoD) Airspace Integration Plan classifies UAS into five groups. Group 1 UAS are hand-launched, self-contained portable systems employed for a small unit or base security. Group 2 UAS are typically small to medium in size and support intelligence, surveillance and reconnaissance (ISR) requirements. Group 3 UAS operate at medium altitude with medium to long range endurance. Group 4 UAS are relatively large, operate at medium to high altitudes and have extended range and endurance. Group 5 UAS are the largest, operate at medium to high altitudes, and have the greatest range, endurance and airspeed capabilities (Department of Defense, 2011). With regards to the integration into the National Airspace System, UAV class is definitely something worth considering since each class occupies a different level or tier of airspace. The challenge is not just about incorporating UAS into the National Airspace System as a whole, but integrating each individual UAS class into the appropriate level of airspace in the NAS. Another concern is the de-confliction of airspace with rotary-wing airframes (which typically fly lower than fixed-wing airframes), and lighter-than-air airframes. Presently, current operation of UAS, with just a few exceptions, is limited to military airspace, meaning on ranges owned and controlled by the military or in zones of military conflict (Austin, 2010), such as Afghanistan or Iraq. The biggest concern with integrating UAS is the potential for collisions between UAVs and manned airframes, or UAVs and other UAVs and the simple fact that there is no dedicated airspace for UAVs. A 2014 NASA Project titled, “Unmanned Aircraft Systems Airspace Operations Challenge,” tasks competitors to develop key technologies that will make UAS integration into the National Airspace System actually feasible. Before UAVs can safely operate in the same airspace as other UAVs or manned airframes, we need to ensure that the operators as well as the unmanned airframes have the ability to successfully “sense and avoid” other traffic. The competition is split into two phases – the first phase focuses on the important aspects of safe airspace operations to include separation assurance, 4-D trajectories, ground control operations and uncooperative air traffic detection. It is aimed at encouraging competitors to get a head start on developing skills for phase two of the competition (NASA, 2014). With regards to existing technology on manned aircraft, they currently operate with transponders or Automatic Dependent Broadcast – System (ADS-B) as well as Airborne Collision Avoidance System (ACAS) installed. This helps manned aircraft identify other aircraft in the airspace and aids in collision avoidance (Airline Pilots Association, 2011). In my opinion, these systems are definitely adaptable for UAS use; but that isn’t the issue with their implementation. The issue at hand is that ultimately, systems cannot completely take the place of a human operator. While there may be a system on board a UAV to detect other airframes in the airspace, it is impossible for a UAS to react to unannounced malfunctions. There are simply things that a pilot can sense on board, be it through smell (smoke indicating a flight issue), touch (vibrations – haptic feedback), etc., that systems on board cannot detect and relay to the human operator on the ground in a timely manner. References Airline Pilots Association (2011). Unmanned Aircraft Systems: Challenges for Safely Operating in the National Airspace System. Retrieved from http://www.alpa.org. Austin, R. (2010). Unmanned Aircraft Systems: UAVs design, development, and deployment. Chichester, U.K.: John Wiley & Sons Ltd. Department of Defense (2011). Unmanned Aerial Systems (UAS) Airspace Integration Plan. Retrieved from http://www.acq.osd.mil/sts/docs/DoD_UAS_Airspace_Integ_Plan_v2_(signed).pdf Embry Riddle Aeronautical University (2014). ASCI 530 Module 4 Presentation – Command, Control, and Communications (C3) Systems. Retrieved from http://ernie.erau.edu. NASA (2014). Unmanned Aircraft Systems Airspace Operations Challenge (UAS AOC). Retrieved from http://www.nasa.gov/directorates/spacetech/centennial_challenges/uas/