UAS Beyond Line of Sight – Boeing Little Bird

The Boeing little bird (H-6U) is an unmanned helicopter based on the AH-I that allows for full autonomous flight capability (Figure 1). The platform provides over the horizon or beyond line of site functionality for surveillance, communications relay, re-supply, and other search related tasks (Boeing, 2016). The H-6U has a operates with a maximum ceiling of 20,000 feet and six hour endurance. Autonomous control is carried out through waypoint control from take-off to landing and reaches a maximum speed of 145 knots true airspeed. Navigation is executed either through a fixed land based station or sea based. The unique ability of the little bird is that the helicopter can be manned and flown by onboard pilots in addition to the platforms unmanned capability as determined by the mission type.

The little bird command link allowing beyond line of site operation utilizes the Ku-band Tactical Common Data Link specifically operated by the U.S. Military for sending secure data and streaming video links to ground stations from aerial platforms (Boeing, 2016). The Ku band used for for communication over the TCDL protocol is a primary method of satellite communications (Tech-FAQ, 2015). The Ku band is found within the 11.7 to 12.7 GHz and 14 to 14.5 GHz frequencies of the electromagnetic spectrum (Figure 2 and 3) for uplink and downlink communication. One of the advantages of the Ku band is that the communication frequency is not restricted by power, which can allow for a decrease in size of the receiving dishes (Tech-FAQ,2015). In addition, the Ku band uplink and downlink power can be increased further, decreasing dish size since the Tactical Common Data Link takes advantage of both directional and omnidirectional antennas to transmit and receive the Ku band signal (Skyware Technologies, 2015). The little bird is also STANAG 4586 compliant, which allows interoperability between other compliant tactical UAS systems amongst allied forces (Lockheed Martin, 2015).

A team is required for operation of the little bird consisting of the pilot, payload operator, and navigation/mission planner. Navigation is pre-planned prior to each mission utilizing waypoints however, changes can occur allowing for dynamic control input by the navigator and pilot. Managing missions based on predetermined flight paths determined by waypoints based on mission type, weather, and other interferences allows for more of a supervisory role by the team during flight to help reduce cognitive workload and stress. Most missions carried out by the platform involve preplanned flight paths for intelligence, surveillance, and reconnaissance. The ground control station is normally located at a fixed location, which can also be aboard a ship at sea (Figure 4).

Flight beyond the line of sight allows for greater ISR abilities but introduces numerous human factors issues. The greatest issue is situational awareness. Flying beyond the line of site restricts the platform operating team to rely on streaming video and flight telemetry data from the UAV to make decisions. Following the proper procedures for any and all emergency procedures is another critical element when flying BLOS. Lost link is a common issue with some UAV platforms that must be dealt with appropriately otherwise the outcome can be catastrophic, especially when flying over inhabited locations. The advantage when operating the little bird is that the platform has vertical take off and landing capability. VTOL allows for a more safely guided emergency landing in almost any location if the lost link procedures fail for any reason or if landing the vehicle in an emergency situation is required.

Each team member part of any unmanned aerial vehicle flying crew operating behind line of sight relies upon open communication, teamwork, and a pilot with strong leadership skills. The increased disconnect between crew and unmanned aircraft requires a higher level of crew resource management understanding, training, and commitment for safe flight operations in all environments when flying beyond line of sight.

References

Artes. (2015). ESPRIT - Artes Programme, Next Generation of Systems, Future Preparations. Retrieved from https://artes.esa.int/projects/esprit

Basu, P. Quora. Retrieved from https://www.quora.com/What-do-you-mean-by-C-band-extended-C-band-and-Ku-band-whats-the-difference-and-what-purpose-does-it-serve

Boeing. (2016). Unmanned Little Bird H-6U. Retrieved from http://www.boeing.com/defense/unmanned-little-bird-h-6u/#/feature-stories

Tech-FAQ. (2015). Ku Band. Retrieved from http://www.tech-faq.com/ku-band.html

Gardiner, G. (2013). Composites aid connectivity on commercial aircraft. Retrieved from http://www.compositesworld.com/articles/composites-aid-connectivity-on-commercial-aircraft

Lockheed Martin. (2015). STANAG 4586. Retrieved from http://www.lockheedmartin.com/us/products/cdl-systems/about-us/stanag-4586.html

Skyware Technologies. (2015). Ka vs. Ku – An Unbiased Review. Retrieved from http://www.skywaretechnologies.com/news/item/84-ka-vs-ku-an-unbiased-review