In the early 2000s, the Federal Aviation Administration (FAA)
began researching options for updating the aging infrastructure of the National
Airspace System (NAS) of the United States. The FAA’s next generation
initiative, or NextGen, was announced in January 2004 in response to direction
published in the Vision 100 - Century of Aviation Reauthorization Act that
assigned the FAA the task of updating the NAS (Houston, 2017). The plan called for numerous changes, most
aimed at addressing safety and efficiency of increasingly crowded airspace. One
of the key components of this series of upgrades is the adoption of a new and
more precise aircraft tracking system. Automatic Dependent
Surveillance-Broadcast (ADS-B) is the technology slated to replace the current
RADAR system as the primary means of tracking aircraft in controlled airspace
(Houston, 2017). ADS-B uses other systems common in today’s aircraft, like
global navigation satellite systems (GNSS), to broadcast aircraft data like
position, speed, planned route, and more to receiving stations on the ground
and in other aircraft. When this data is received it can be collected to build
an extremely accurate model of the surrounding airspace and used to bolster the
situational awareness of pilots and air traffic controllers alike. In order to
maximize the effectiveness of the system in the NAS, the FAA has mandated the
ADS-B transponder as required equipment for flight in a majority controlled
airspace by January 1, 2020.
Those
responsible for crafting the NextGen plan did so with the expectation the NAS
congestion would continue to present issues, and the plan did well at
addressing the issues known at the time. What was not foreseen was the
exponential growth in unmanned systems, specifically small unmanned aerial
systems (sUAS). The FAA Aerospace
Forecast for Fiscal Years 2017-2037 published the number of sUAS estimated at
4.47 million hobbyist aircraft and 1.616 million commercial aircraft (FAA
Aerospace Forecast, 2017). This number dwarfs the amount of conventionally
manned aircraft. The threat of an increasing number of sUAS potentially sharing
airspace with manned aircraft was significant enough to cause the federal and
state regulations stymie sUAS growth just as the boom began. Fortunately, the
FAA was quick to adapt with release of 14 CFR Part 107. The regulation enables
commercial operators to fly sUAS within specified parameters. Thus far, there
is not a stated specific requirement for sUAS to be equipped with ADS-B, but
the FAA mandate was issued with consideration for sUAS and applies to all
aircraft with few exceptions. However, the addition of such a capability would
offer an increased margin of safety for manned and unmanned aircraft.
Until
recently, the possibility of including ADS-B technology in sUAS design was not
thought likely due to the size and weight of transceivers. Weight directly
affects aircraft performance, and even the smallest changes in weight can have
significant impact on a sUAS. uAvionix, an aircraft avionics producer, has
developed a micro sized ADS-B transceiver to address this shortfall. The
Ping2020 is being marketed as the “world’s smallest and lightest full range
ADS-B transceiver” (Ping2020, 2016). Per the uAvionix website, the Ping2020
measures 25mm x 39mm x 12mm and weighs 20 grams, and meets the following
specifications:
• Detects
aircraft threats on 1090MHz and 978MHz within 100 statute mile radius in real
time
• Reports
threats from aircraft in a programmable spherical radius
• Transmits
ADS-B on 978 MHz at 20W nominal
• Meets
MOPS DO282B Class A1S
• Navigation
Source (GPS and Baro) FYXnav-B option
• SMA
Antenna Connector
• GDL90
combined UAT and 1090ES traffic reports
• Direct
integration with Pixhawk Autopilot
• Integration
with DJI via DJI Software Development Kit (Ping2020, 2016)
This
sensor is ideal for incorporation as an integral component of a comprehensive
sense and avoid system. While stereo cameras, LIDAR, and small aperture radar
are the preferred sensor options for obstacle avoidance, their limited range
neglects long range and potentially fast-moving threats. They also do not
broadcast position information. ADS-B fills this capability gap and could
contribute to making beyond visual line of sight (BVLOS) operation of sUAS
feasible and safe. As can be gleaned from the system specifications the
Ping2020 maintains capabilities similar to larger systems with little negative
effect on performance due to its light weight and size. The fact that the system
integrates with DJI and the Pixhawk Autopilot make it even more appealing. As a
sense and avoid sensor the ADS-B is relatively new to sUAS, but stands to
revolutionize the largest segment of aviation by numbers.
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| Ping 2020 sUAS ADS-B transceiver. Image as published on uAvionix website. Retrieved from https://www.uavionix.com/products/ping2020/ |
References
FAA Aerospace Forecast. (2017). Federal Aviation
Administration. Retrieved from https://www.faa.gov/data_research/aviation/aerospace_forecasts/media/FY2017-37_FAA_Aerospace_Forecast.pdf
Houston, S. (2017, June 25). NextGen in a Nutshell. The
Balance. Retrieved from https://www.thebalance.com/nextgen-in-a-nutshell-282561
Ping2020. (2016). uAvionix. Retrieved from https://www.uavionix.com/products/ping2020/
