IEEE - Aerospace and Electronic Systems - March 2021 - 8

Counter-Unmanned Aircraft System(s) (C-UAS): State of the Art, Challenges, and Future Trends
Table 3.

Airspace Restrictions Applicable to UAS by FAA (March 2020)
Stadiums

Airports

Operations are prohibited within a radius of three nautical miles. Operations
are prohibited starting one hour before and ending one hour after scheduled
time of important events.
1. One must have a Remote Pilot Certificate and get permission from Air
traffic control (ATC). 2. Model aeroclub organization must notify the airport
operator and control tower to fly within 5 miles. 3. Public entity (law
enforcement or government agency) may apply for special permission.

Security sensitive
airspace

Operations are prohibited from the ground up to 400 feet above ground level.

Capital areas

Varying according to the policies of government, in Washington, DC.,
airspace is governed by a Special Flight Rules Area (SFRA), UAS operations
are restricted within a 30-mile radius of Ronald Reagan Washington National
Airport (15-mile inner ring: prohibitted without specific permission from
FAA; 15 to 30 miles outer ring: registered, light and small UAV can fly lower
than 400 feet and visual range in clear weather).

Restricted or Special Use
Airspace

Certain areas where drones and other aircraft are not permitted to fly without
special permission, or where limitations must be imposed for any number of
reasons.

Temporary Flight
Restriction (TFR)
Emergency and Rescue
Operations

A TFR defines a restricted airspace due to a hazardous condition or specific
events. List of TFR can be found at https://tfr.faa.gov/tfr2/list.html
FAA prohibits drones over any emergency or rescue operations. It's a federal
crime to interfere with firefighting aircraft regardless of whether restrictions
are established.

AIRSPACE RESTRICTIONS APPLICABLE TO
UAS FLIGHTS
In the United States, there are several types of airspace
restrictions that commonly affect UAS flights [31], as shown
in Table 3. From the table, the most stringent restrictions are
security sensitive airspace restrictions which prohibit UAS
operations from the ground up to 400 feet above ground level,
and apply to all types and purposes of UAS flight operations;
for stadiums and sporting events, restrictions are valid during
gathering of the crowds; Washington DC has the largest spatial restriction circle (30 miles).
The FAA established a series of rules and regulations
which apply to UAS operations, based on the type of UAS
flier: recreational fliers and modeler community-based
organizations, certificated remote pilots including commercial operators, public safety and government, and educational users [1]. UAS that weigh more than 0.55 pounds
must be registered with the FAA. In addition, flying UAS
that are less than 55 pounds for work or business requires
remote pilot certificates [1].
Although the FAA has established guidelines and regulations, and reports of UAS sightings from pilots, citizens, and law enforcement have increased dramatically
8

over the past five years, as shown in Figures 1 and 2.
Therefore, there is an urgent need for promoting safe,
secure, and privacy-respecting UAS operations. We envision that an integrated system capable of detecting and
negating UAS will be essential to the safe integration of
UAS into the airspace system. Such a system needs novel
technologies in the following two main areas.
Detection: The ideal UAS detection will detect,
track, and identify an unmanned aircraft or UAS,
have a small footprint, support highly automated
operations and location functions.
Mitigation: The ideal UAS mitigation system will
lawfully and safely disable, disrupt, or seize control of an unmanned aircraft or UAS, while
ensuring low collateral damage and low cost per
engagement.
A survey of UAS detection and mitigation is the first
step in leveraging communications and signal processing
to develop low footprint UAS detection solutions, in terms
of size, weight, power, and manning, as well as varied and
low collateral damage UAS mitigation techniques and
effectors, towards safe integration of UAS into the airspace system.

IEEE A&E SYSTEMS MAGAZINE

MARCH 2021

https://tfr.faa.gov/tfr2/list.html

IEEE - Aerospace and Electronic Systems - March 2021

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