4.5 - Research: UAS Beyond Line of Sight Operations
Greg D. Laxton
ASCI 638
– Human Factors in Unmanned Aeronautical Systems
Embry-Riddle
Aeronautical University-Worldwide
5 February
2017
Pathfinder FAA
Program
The Boeing Insitu ScanEagle has been
involved in domestic U.S. BLOS tests, as part of the FAA Pathfinder program (Federal Aviation Administration, 2016). The Pathfinder program had three focus areas, VLOS over
people, longer range VLOS in rural areas and BLOS operations in more isolated
areas of the country (Federal Aviation Administration, 2016). The ScanEagle participated in the third part of the
Pathfinder program during the fall of 2015 in conjunction with BNSF Railway (SUAS
News, 2015).
The goal
of this particular New Mexico test was to demonstrate how UAS can operate BLOS
domestically and support critical infrastructure inspection. The ScanEagle successfully
provided video in real-time over a 64 miles of railroad track (SUAS News, 2015).
The next phase BNSF will undertake is to bring Automatic
Dependent Surveillance-Broadcast (ADS-B) or other position reporting
information back to the GCS from fixed sensors along the UAS route (Washington, 2016).
Fixed Sensors Along UAS Route
The idea involves placing sensors at predetermined points along
the route to be inspected. The sensors for this project were deployed by the
Harris Corporation, a Melbourne, Florida based technology company heavily
involved in air traffic management. It placed its ADS-B Xtend sensors, which is
portable, at intervals along the railroad track. These sensors are battery
powered, tubular shaped and approximately a foot and a half long. The Xtend can
receive “transponder signals on 1090 MHz and 978 MHz frequencies as far away as
150 mi” (Croft, 2016). No
additional people are needed once the sensors are placed along the inspection
route and they use a cellular signal to transmit the data back to the GCS. The
sensors greatly increase the ADS-B signal and provides a much better picture of
the operating area back to the GCS.
The Xtend tests should provide
data to the BNSF GCS through the “Harris’s web-based
Symphony RangeVue application” (Washington,
2016).
This is a product that combines ATC traffic information, weather and airspace
restrictions and displays them for the UAS operator on a laptop or any web
connected display device (Washington,
2016).
Advantages
and Disadvantages of Fixed Sensors
Fixed sensors have
the ability to augment command and control signals to a UAS, but with the
obvious disadvantage of limiting the planned flight route. The Pathfinder test
with BNSF is ideal for fixed sensors, because the railroad tracks must be
inspected and do not usually move. A key aspect of this test was demonstrating
to the FAA that UAS can operate BLOS and still stay connected to an ATC system
and display ADS-B data to other aircraft and back to the operator. The ability
to see all traffic in the vicinity is clearly a concern for FAA considering
integrating UAS in the NAS. This may be a path to success.
Human
Factor Issues
If UAS operators
are confident they have a clear picture of other traffic operating near their
aircraft, this should help maintain situational awareness for manned and
unmanned aircraft. Decision making ability for pilots should be easier when all
the traffic can clearly “see” each other, know their altitude with the ADS-B
signal, and take appropriate action to avoid a collision. The Symphony RangeVue
depiction and a clear awareness of other traffic in the area should lead to an
increased situational awareness for the UAS operator and help in the transition
from BLOS to LOS.
Commercial
Applications
The ADS-B Xtend
devices may lead the way in fixed observation situations such as pipeline and
rail inspection. Railroad inspections are labor intensive and utilizing UAS
should offer a clear economic advantage. The BNSF and FAA Pathfinder program is
a good example for this industry.
One downside of many more fixed ADS-B transmit / received
devices like Xtend, is task saturation of the system. Divas reports that once
the UAS level rises to more than five per square kilometer, “co-channel
interference” is likely (Divas,
2016). This may eventually limit the maximum number of users in a geographic
area, reducing the advantage of a fixed sensor system, but it does offer a
clear path forward for BLOS UAS operations in the NAS.
References
Croft, J.
(2016, May 13). Railway Company To Test sUAS Methods For Track Inspections.
Retrieved from awin.aviationweek.com.ezproxy.libproxy.db.erau.edu
Divas, D. A.
(2016, May 16). Obstacles Appear to Extending GPS-Based ADS-B for UAV
Operations | Inside GNSS. Retrieved from http://insidegnss.com/node/4944
Federal
Aviation Administration. (2016, June 14). Focus Area Pathfinder Program.
Retrieved from https://www.faa.gov/uas/programs_partnerships/focus_area_pathfinder/
SUAS
News. (2015, November 25). Insitu and BNSF ScanEagle first commercial BVLOS
flight. - sUAS News - The Business of Drones. Retrieved from
https://www.suasnews.com/2015/11/insitu-and-bnsf-scaneagle-first-commercial-bvlos-flight/
Washington, G. W.
(2016). Mobile ADS-B Enables Beyond-Line-of-Sight UAS. Aviation Week and
Space Technology. Retrieved from
http://awin.aviationweek.com.ezproxy.libproxy.db.erau.edu/
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