Design of Sense-and-Avoid Standards for

RQ-7B Shadow under Loss-Link

Jonathan E. Pearson, Zachary Moore, John S. Ogdoc, Francisco J. Choi

performing these and many more missions without a pilot on

Abstract - Since 2008, the demand for Unmanned board. This has led to a constant rise in demand for
Aircraft Systems (UAS) within the National Airspace advancements in UAS technology across the globe. As the
System (NAS) has more than doubled. The demand for UAS’s increases, the number of flight hours has
Congressional Mandate of 2012 tasked the Secretary of also increased, shown below in Fig. 1 [4]. It is projected that
Transportation to develop a comprehensive plan to safely by 2013, the Department of Defense (DoD) will perform over
accelerate the integration of UAS into the NAS by 2014. one million flight hours of UAS operations.
A major concern with integration is Sense-and-Avoid
(SAA) capabilities of UAS. This paper describes the
design for the standard for onboard UAS sensors which
meet the Target Level of Safety (TLS) of 𝟏𝟎−𝟕 , or 1
incident in 10,000,000 flight hours, set forth by the
Federal Aviation Administration’s (FAA) System Safety
Handbook (SSH). To successfully perform SAA the RQ-
7B Shadow needs a total of 5.73 seconds to detect and
maneuver safely to avoid an incident with another
aircraft. The hardware to satisfy these design Figure 1: UAS Flight Hours
requirements is the POP300D sensor. C. Key Issues
I. CONTEXT The increase in demand for UAS’s and corresponding
increase in flight hours within the NAS leads to a number of
A. National Airspace System key issues which must be addressed. Many of these issues

T he National Airspace System (NAS) is a collection of

procedures, regulations, infrastructure, aircraft and
personnel comprising the national air transportation
stem from the fact that there is no pilot onboard the UAS. A
UAS places the pilot at a Ground Control Station (GCS) and
controls the aircraft through a command-and-control (C2)
system in the United States. It is governed by US law and link. Figure 2 depicts the differences between manned and
Federal Aviation Regulations (FAR) set forth by the Federal unmanned systems. The biggest key issue then is that the
Aviation Administration (FAA), which govern the design and pilot of the UAS cannot perform see-and-avoid maneuvers,
operation of aircraft which operate within the NAS. The the last line of defense in collision avoidance and the
FAA is granted the authority to set rules and regulations responsibility of the pilot, in the same manner as a manned
which guide the NAS by Title 49 of the United States Code aircraft. Because UAS lack the ability to perform see-and-
(49 U.S.C.) [1]. Subtitle 1 of 49 U.S.C. governs the avoid, the GCS pilot must rely on the onboard sensors that
Department of Transportation, where the FAA resides and the UAS is equipped with to perform sense-and-avoid (SAA)
Subtitle VII governs aviation programs. maneuvers.
B. Expanding Roles of UAS’s Another issue that arises from the need for SAA
capabilities is the possibility of losing the C2 link while the
The Unmanned Aircraft System (UAS) is an invention UAS is in flight. To account for this possibility, UAS
created to maintain air superiority since man first took to the operators create a set of pre-programmed procedures for the
skies. Major Norman E. Wells wrote: “to win, you must UAS to execute if a loss of link occurs.
control the skies – particularly the skies over your own These issues complicate the next key issue: there are no
territory. Air power does not guarantee that you will win a set standards or regulations for the manufacturing &
war, as in the cases of Korea and Vietnam; but without it, certification or operation of UAS in the NAS. A manned
modern armies are destined to lose” [2]. UAS are a aircraft is issued an airworthiness certificate based on FAA
mechanism utilized to achieve air superiority, making their regulations set in the FAR that allows the aircraft to fly in the
applications primarily military; however, UAS can also serve NAS. However, there are no standards to determine that a
in a variety of other capacities including remote sensing for UAS is airworthy. FAA Order 7610.4K: Special Military
terrain mapping, meteorology monitoring and precision Operations gave the DoD a Certificate of Authorization
agriculture, disaster response, homeland security, through (COA) which allows them to operate UAS in the NAS, but
surveillance of traffic along borders and the coast, search and the COA does not ensure the UAS is airworthy [5]. This lack
rescue, cargo transport, and delivery of water to firefighting of standardization creates a gap that the FAA must address.
efforts or chemicals for crop dusting [3]. UAS are capable of
 NAS in order to carry out their missions (shown in Figure
4). Specifically these missions include the following:
The DoD reports the use of 146 UAS based at 63
continental United States locations. By 2015, it is estimated
to have 197 units at 105 locations [4]. In order for the DoD
to maintain combat readiness, military agencies need to
perform specific missions that require access to the NAS.
Missions for UAS’s require real world conditions for
Figure 2: Manned VS Unmanned crewmember, pilot, and maintainer training.
The DHS intends to use UAS in the NAS for border
D. Effort towards UAS Integration
protection for terrorism prevention, illegal drug or
The FAA Reauthorization Bill, passed in 2011, tasked the contraband trafficking, or other criminal offences.
FAA to develop a comprehensive plan to safely integrate National Aeronautics and Space Administration (NASA)
commercial UAS into the NAS [6]. This general order for demand UAS operations for aeronautical and scientific
the FAA was given a time schedule by Congressional research. These missions include atmospheric sampling,
Mandate in the FAA Modernization and Reform Act of 2012 hurricane science, and earth surface measurements.
to safely accelerate UAS integration into the NAS [7]. The
Congressional Mandate pointed out three major areas to A. Key Issues
tackle for integration to become a reality: standards for The FAA faces challenging safety concerns that hold
operation, civil UAS certifications, and SAA capabilities. back the integration for UAS’s to fly in the NAS. These
issues include the following:
E. Sense and Avoid
1. Currently there is no standardization requirements for
The FAA defined SAA in 2009 as “the capability of a SSA procedures
UAS to remain well clear and avoid collisions with other 2. Current SSA technology is not as good as See and
airborne traffic” [8]. The sense half of SAA, is defined by the Avoid procedures on a manned aircraft.
azimuth, elevation and detection range of onboard sensors. 3. Economic issues that include cost in development,
The avoid half of SAA, is accomplished by programming the awareness, and education.
UAS to make decisions after detecting an intruder aircraft
according to 14 CFR 91.113: Right-of-Way Rules: Except B. Tensions and Conflicts
Water Operations [9]. As the use of UAS increases and the need to access
SAA capabilities will be at an acceptable level when a civilian airspace is prevalent, the concern of safety is the
UAS can remain well clear and avoid not only collisions but main tension before the FAA can implement this integration.
also conflicts, when there are less than 500 feet separating the Other conflicts include the workload on the air traffic
UAS from another aircraft. controller, and the robustness of SAA procedures. Unions
F. Target Level of Safety (TLS) such as the ACLU and AOPA oppose the widespread
operations of drones and create tension (voyeurism,
To assess UAS SAA capabilities in terms of safety, or discriminatory targeting, and institutional abuse) with the
risk of collision, a clear understanding of how the FAA FAA. Figure 3 below shows the conflicts and tensions
defines risk in the NAS is needed. The FAA Systems Safety among stakeholders. Other stakeholders include Air Traffic
Handbook (SSH) defines risk as “the likelihood of an Controllers, Ground Station Pilots and Manned Aircrafts.
accident, and the severity of the potential consequences”
[10]. The likelihood of an accident is measured by the
number of incidents per flight hour expressed as an order of
magnitude, separated into four classifications. The likelihood
of an accident ranges from a ‘probably’ event, or 1 accident
per 1,000 flights hours, to an ‘extremely improbable’ event,
or 1 accident per 1,000,000,000 flight hours. The FAA SSH
has set a Target Level of Safety (TLS) for all operations in
Figure 3: Stakeholder Interactions
the NAS to keep accidents in the ‘extremely remote’ range.
This corresponds to a 10-7 order of magnitude, or less than 1 III. PROBLEM STATEMENT
accident per 10,000,000 flight hours. UAS operations must
achieve this TLS before the FAA will allow full integration Since the task of identifying possible conflicts and
of manned and unmanned flights in the NAS. avoiding them is the responsibility of the human operator, a
UAS operating under a loss of link scenario must have Sense-
II. STAKEHOLDER ANALYSIS and-Avoid capabilities which, when performed
There is an effort from Congress and the FAA to automatically, meet the 10-7 TLS set forth by the FAA SSH
integrate UAS into the NAS. Current demands for UAS in A. Gap
the NAS need accommodation from the FAA. Main agencies
SAA capabilities fail to ensure the TLS set by the FAA
include the DoD, DHS, and NASA need UAS’s to in fly in
SSH. This creates a gap between UAS capabilities to
maintain the TLS set forth by the FAA SSH. This gap can be Resolution is the only factor affecting the UAS ability to
shown in the figure below. detect intruder aircraft. An ideal E-O/IR sensor would have a
full 360° Field of View (FOV) and infinite detection range;
however, this is entirely infeasible. In actuality, resolution is
set, and a tradeoff exists between the FOV and detection
range. Simply put, if the E-O/IR sensor is given a large FOV
versus a small FOV to passively scan, the distance at which it
can detect an object will decrease.
V. DESIGN ALTERNATIVES
The RQ-7B Shadow is currently equipped with the POP
300 EO/IR sensor which has the parameters shown in Table
1. In addition, the table shows the parameters for the
POP300D, a higher resolution sensor also produced by Israel
Aerospace Industries Inc. (IAI). The POP300 and POP300D
sensors will be used to conduct the sensitivity analysis by
varying the sensors’ azimuth and detection range.

Figure 4: Gap Shown between SAA Capabilities and the Table 1: POP300 vs. POP300D Sensor Configuration
TLS. Parameters [12], [13]
B. Need Statement
There is a need for SAA methodology that allows for
UAS operating under loss-of-link to detect and avoid other
aircraft allowing UAS to maintain the TLS of 10−7 set forth
by the FAA while flying in the NAS.
IV. SCOPE AND PROJECT REQUIREMENTS
VI. METHOD OF ANALYSIS
To analyze SAA capabilities with sufficient accuracy to
give recommendations to improve collision risk in the NAS, The Method of Analysis has three main components:
a few assumptions need to be made which define the scope of Phase 1 Simulation, Gas Model of Aircraft Collisions and
the project. This design is scoped by the following three Phase 2 Model of detection sensor performance. Phase 1 is a
constraints. Monte Carlo simulation of an airspace which generates
probabilities and distributions for use in the Gas Model and
A. Airspace Classification Phase 2 Model. The Gas Model of Aircraft Collisions uses
For the scope of the project, all aircraft will be operating the distribution of relative velocities of simulated aircraft to
within Class E airspace [11]. predict the Expected Level of Safety (ELS) of the airspace.
Phase 2 is a model which provides the ELS for each design
B. UAS Selection
alternative.
The UAS selected for the scope of the project is the RQ-
7B Shadow. The RQ-7B Shadow is the primary airborne A. Phase 1 Simulation Assumptions
intelligence, reconnaissance and surveillance (ISR) UAS for The model has 7 assumptions. First, all aircraft are
the Army, Marine Corp and USCOMM units. The RQ-7B operating in the x-y plane, meaning that they are in level
flies between 3,000 ft. AGL and 18,000 ft. AGL, placing it flight and do not change altitude. The number of aircraft, N,
completely within Class E airspace [4]. The RQ-7B will be in the airspace is 2 at all times. The velocity of other aircraft
operating under a loss of link. In other words, the RQ-7B will will have a normal distribution with a mean of 126.5 knots
have to perform SAA automatically, with no input from the and a standard deviation of 22.5 knots. The horizontal
GCS pilot. Other aircraft are assumed to be uncooperative dimension of other aircraft will have a normal distribution
and will not perform see-and-avoid maneuvers. with a mean of 891.2 ft2 and a standard deviation of 12.8 ft2
[14]. The initial locations of aircraft entering the airspace will
C. Electro-Optic / Infrared Sensors
have a uniform distribution between 0 and 359 degrees. In
Electro-Optic Infrared Sensors work in tandem as a addition, there will at all times be only 2 aircraft occupying
complete system. The Electro Optic sensor takes pictures in the airspace. Finally, the aircraft entry headings will also be
the visible light spectrum with a charged coupled device uniformly distributed between varying ranges depending on
(CCD) camera. The infrared sensor takes pictures within the what side of the airspace they enter.
infrared spectrum, making detections based on temperature
differentiation. The largest factors in the cost of a complete B. Phase 1
E-O/IR sensor system are the weight and resolution. Since Phase 1 is a Monte Carlo Simulation with the following
the RQ-7B can carry up to 110 lbs. E-O/IR sensor, any input parameters:
representative sensor must not exceed this limitation [4].  Initial coordinates - (x,y)
  UAS and manned aircraft velocities – v well as the remaining time until the detected aircraft becomes
 Aircraft headings – p a NMAC. The fraction of NMACs detected is calculated by
 Diameters of the aircraft – g. equation 4. If an aircraft does not enter the sensors FOV or is
The UAS will always be located at the center of the outside the detection range, it is not possible for the sensor to
airspace for the simulation with coordinates (0, 0), a constant detect the aircraft.
velocity of 70 NM/h, a constant heading of 90º N, and a # 𝑁𝑀𝐴𝐶 𝐷𝑒𝑡𝑒𝑐𝑡𝑒𝑑
𝐹𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑁𝑀𝐴𝐶𝑠 𝐷𝑒𝑡𝑒𝑐𝑡𝑒𝑑 = (4)
diameter of 14 ft. 𝑇𝑜𝑡𝑎𝑙 # 𝑜𝑓 𝑁𝑀𝐴𝐶
The simulation begins by generating an aircraft with Equation 5 represents the total time it takes for the RQ-7B
values for its velocity, v, and its area g. The simulation then to perform SAA, comprised of the time it takes to detect an
randomly chooses a side of the airspace that the aircraft will aircraft, make a decision and execute that decision [16].
enter from, and uses that value to determine its initial x and y 𝑡𝑡𝑜𝑡𝑎𝑙 = 𝑡𝑑𝑒𝑡𝑒𝑐𝑡 + 𝑡𝑤𝑎𝑟𝑛 + 𝑡𝑡𝑢𝑟𝑛 (5)
coordinates as well as its heading p. Since E-O/IR sensors scan the FOV passively, it is
Using these inputs Phase 1 simulates 10,000,000 hours of assumed that 𝑡𝑑𝑒𝑡𝑒𝑐𝑡 is instantaneous. Because the RQ-7B is
flight time for the RQ-7B Shadow. Throughout the performing SAA automatically with no C2 link, the time
simulation all relative velocities between the RQ-7B and required to relay information to the GCS pilot, 𝑡𝑤𝑎𝑟𝑛 , is also
another aircraft were found using the following equation assumed to be instantaneous. Therefore, the total time
[15]. required to perform SAA while operating under a loss of link
𝑉𝑟 = (𝑣𝑖2 + 𝑣𝑗2 − 2𝑣𝑖 𝑣𝑗 𝑐𝑜𝑠 𝛽) 1/2 (1) is given by the time required to execute a turn, calculated by
The relative angle of the two aircrafts, β, is calculated by equation 6.
projecting the vector of aircraft j, onto aircraft i. The outputs 𝜋
𝑡𝑡𝑢𝑟𝑛 = 5.6 ∗ √ − 𝜙 (6)
from Phase 1 are shown below: 2

 Expected Relative Velocity – E[𝑉𝑟 ] The banking angle of the RQ-7B, ϕ, is assumed to be 30°,
 Number of Near Mid-Air Collisions (NMAC) which represents a load factor of 1.2, well within load factor
 Total Number of Aircraft Generated in Phase 1 limitations for small aircraft [17]. With this value for the
Expected Relative Velocity, E[𝑉𝑟 ], was calculated by banking angle, the time needed to make a turn to avoid a
simply averaging all of the recorded relative velocities for NMAC is 5.73 seconds, found using equation 6.
each generated aircraft with respect to the RQ-7B Shadow. Therefore , 𝑡𝑡𝑜𝑡𝑎𝑙 , or the total time needed for the RQ-7B
Near midair collisions (NMAC) are defined as any incidence Shadow to detect and avoid an aircraft is 5.73 seconds.
where a manned aircraft comes within 500 ft. of the RQ-7B E. Sensor Analysis
Shadow. Finally, the Actual Level of Safety (ALS) for the
The POP 300 sensor has an IR detector lens that is 640
airspace is defined as the probability of a collision, shown
pixels x 480 TVL [12]. The POP300D sensor has an IR
below in equation 2.
# 𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛𝑠 detector lens that is 1280 pixels x 1204 TVL [13]. The
𝑃(𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛) = (2) assumption that all aircraft operate only in the x-y plane
# 𝑡𝑜𝑡𝑎𝑙 𝑓𝑙𝑖𝑔ℎ𝑡 ℎ𝑜𝑢𝑟𝑠
implies that the z-plane will not be visible to our sensor. So
C. The Gas Model [15] the IR lens for the POP300 sensor is reduced to 1 pixel x 480
The Gas Model of Aircraft Collisions is a prediction of TVL and the POP300D sensor is reduced to 1 pixel x 1204
the airspace’s ELS as a comparison to the ALS. The Gas TVL. TV Lines are a bit smaller than pixels. TV Lines can
Model uses the following inputs to calculate the ELS. be converted to pixels using:
 E[𝑉𝑟 ] 1 𝑇𝑉𝐿 = 0.75 𝑝𝑖𝑥𝑒𝑙𝑠 (7)
 E[g] - Expected area of aircrafts in airspace Equation 7 gives the number of pixels that will be used
 N - Number of aircraft in airspace for each sensor to analyze its detection performance. Using
 A - Area of airspace the provided sensor parameters, manned aircraft velocities,
With these values the Gas Model applies the following and manned aircraft areas the maximum distance that the
formula to determine the ELS. POP300/POP300D sensors can detect an intruding aircraft
2 ∗ 𝑔 ∗ 𝐸[𝑉𝑟 ] can be found. For the analysis it is assumed that the only
𝐸𝐿𝑆 = (𝑁 − 1) (3) object that will be large enough for detection is the other
𝐴
The difference between the ALS and ELS represents the aircraft in the airspace with the RQ-7B Shadow.
gap which can be closed by improved technology and First, the minimum detection threshold, Ω, is defined as
utilization of that technology. If the ELS is found to be the minimum projected angle that the manned aircraft
greater than the ALS then the Phase 1 simulation data will be subtends onto the pixel array grid [18]. For this simulation,
deemed invalid. the minimum detection threshold is one pixel; therefore, Ω
for each design alternative is found using equation 8.
D. Phase 2 1
The goal for Phase 2 is to determine a sensor, or sensors, Ω= 𝑝𝑖𝑥𝑒𝑙𝑠
(8)
which allow the RQ-7B Shadow to detect intruding aircraft (# 𝑠𝑒𝑛𝑠𝑜𝑟𝑠) ∗ ( )
𝑠𝑒𝑛𝑠𝑜𝑟
with enough time to make a maneuver. Phase 2 analyzes the In addition to Ω, it is necessary to find the degrees per
fraction of NMACs detected by each design alternative as pixel for each design alternative. The FOV represents the
number of degrees which the E-O/IR sensor must passively B. Gas Model Results
observe. Equation 9 divides the total degrees in the FOV by The Phase 1 simulation generated an E[𝑉𝑟 ] of 120.70
the number of pixels for the design alternatives. The degrees NM/hr. Using equation 3, the Gas Model predicts an ELS of
per pixel represent the minimum angle that will be subtended 4.89E-05. Since the ELS is smaller than the ALS, our Phase
onto the sensor lens which allows the RQ-7B Shadow to 1 results can be considered valid and improvement to safety
𝐹𝑂𝑉 °
detect an aircraft. =𝜃 ( ) (9) in the simulated airspace is possible through SAA.
𝑝𝑖𝑥𝑒𝑙𝑠 𝑝𝑖𝑥𝑒𝑙
Each aircraft which becomes a NMAC during the Phase C. Phase 2 Results
1 simulation has a particular aircraft dimension generated by Phase 2 models the ELS for each design alternative based
the distribution of g when the aircraft was created. Equation on their resolution and azimuth. Table 2 depicts the design
10 calculates the detection range as a function of θ and the alternatives analyzed. The sensor and resolution columns
horizontal dimension of the NMAC. Figure 5 depicts describe which sensor was used and how many were
graphically how this equation is derived. analyzed. The azimuth column describes the number of
𝑔 degrees left and right of the nose the sensor(s) passively
𝑑= (10)
tan 𝜃 scanned. These design alternatives resulted in the fraction of
NMACs detected based on the azimuth and the time
remaining before the aircraft becomes a NMAC based on
detection range.
Figure 5: Detection Range Derivation Table 2: Table of Sensor Performance
Sensor Resolution Azimuth % NMACs Det. TBN (Seconds)
VII. RESULTS POP300 640 90 0.1812 8.88
A. Phase 1 Results POP300 640 110 0.3150 7.19
POP300 640 130 0.4941 5.90
The simulation of 10,000,000 flight hours led to 2x POP300 1280 130 0.4956 12.91
24,471,439 aircraft being generated, resulting in 56,887 2x POP300 1280 150 0.7091 11.09
NMACs. This corresponds to a probability of a NMAC, 2x POP300 1280 170 0.9295 9.73
P(N), of 5.56E-03. In other words, approximately 5 in every POP300D 1605 180 0.9999 11.92
1000 aircraft will fly within 500 feet of the UAS. 2x POP300D 3210 180 0.9999 25.10
3,095 of the 56,887 NMACs resulted in a collision. This The results for a single POP300 sensor at 90, 110 and 130
corresponds to an ALS of 3.03E-04 for the simulated airspace degrees azimuth verify that as azimuth increases, the fraction
when the RQ-7B Shadow does not perform any SAA of NMACs detected increases while the time before the
maneuvers. aircraft becomes a NMAC decreases. At 130°, a single
Finally, the probability of a collision given a NMAC, POP300 sensor detects approximately half of the NMACs
P(C|N) is found using Bayes’ Theorem, assuming the and barely provides enough time to execute an avoidance
probability of a NMAC given a collision is 1, seen in maneuver.
equation 11. Next, an analysis was performed with two POP300
𝑃(𝑁|𝐶) ∗ 𝐴𝐿𝑆 sensors at 130, 150 and 170 degrees azimuth. The percentage
𝑃(𝐶|𝑁) = (11)
𝑃(𝑁) of NMACs detected increases to approximately 93%;
Figure 6 is a plot of NMACs at when the manned however, the average time remaining before the aircraft
aircraft breaches the 500ft range and becomes a conflict. The becomes a NMAC is only 9.73 seconds.
plot has X, Y ranges that are just large enough to show the Finally, the POP300D sensor was analyzed with an
189,573 ft2conflict zone in the airspace surrounding the RQ- azimuth of 180°, its design specification. A single POP300D
7B Shadow. detected nearly 100% of NMACs, and provided an average
of 11.92 seconds to perform an avoidance maneuver. When
two POP300D’s were equipped, the time to perform an
avoidance maneuver increased to 25.10 seconds. While this
is certainly preferable, the cost to increase the detection range
by adding a second POP300D sensor may exceed what UAS
manufacturers wish to spend if a single sensor meets the
TLS.
To determine which of these alternatives meet the TLS,
the ELS for each design alternative were calculated using
equation 12.
𝐸𝐿𝑆 = (1 − %𝑁𝑀𝐴𝐶𝑠 𝐷𝑒𝑡. ) ∗ 𝑃(𝐶|𝑁) ∗ 𝐴𝐿𝑆 (12)
As you can see in Table 3 below, only the POP300D
meets the TLS, with ELS of 2.03E-09.
Figure 6: NMACs resulting from non-overtaking aircraft
 Table 3: ELS for RQ-7B Shadow SAA Capabilities [5] Federal Aviation Administration. Order 7610.4K: Special
Sensor Resolution Azimuth % NMACs Det. TBN (s) ELS Military Operations. 19 Feb. 2004.
POP300 640 90 0.1812 8.88 1.35E-05 [6] Unmanned Systems Integrated Roadmap FY2011-2036. 2011.
POP300 640 110 0.3150 7.19 1.13E-05 [7] FAA Modernization and Reform Act of 2012: Conference
POP300 640 130 0.4941 5.90 8.33E-06 Report. 1 Feb. 2012.
2x POP300 1280 130 0.4956 12.91 8.30E-06 [8] Federal Aviation Administration. Sense and Avoid (SAA) for
2x POP300 1280 150 0.7091 11.09 4.79E-06 Unmanned Aircraft Systems (UASs). Oct. 2009.
2x POP300 1280 170 0.9295 9.73 1.16E-06 [9] Code of Federal Regulations. Part 91: General Operating and
POP300D 1605 180 0.9999 11.92 2.03E-09 Flight Rules.
2x POP300D 3210 180 0.9999 25.10 2.03E-09 [10] FAA Systems Safety Handbook. 30 December, 2000.
[11] Code of Federal Regulations. Part 71: Designation of Class A,
VIII. CONCLUSIONS AND RECOMMENDATIONS B, C, D, and E Airspace Areas; Airways; Routes; and
The RQ-7B Shadow has a cruising speed much slower Reporting Points.
[12] Israel Aerospace Industries. POP300: Lightweight Compact
than other aircraft present in the airspace and most NMACs
Multi Sensor Stabilizing Plug-in Optronic Payload. Web. 30
happened from aircraft approaching the UAS from behind. Mar. 2013.
Because of this reality, the RQ-7B needs to be able to scan a [13] Israel Aerospace Industries. POP300D-HD High Definition
360° FOV to assure it meets the TLS. The POP300D was the Plug-In Optronic Payload – ‘Designator.’ Web. 30 Mar.
only sensor that allowed the RQ-7B to scan a full 360° FOV 2013.
with enough time remaining to avoid NMACs and [14] Cessna 172. Wikimedia Foundation, 29 Mar. 2013. Web. 31
consequently avoid collisions. Therefore, the POP300D is Mar. 2013.
the only design alternative which assures the RQ-7B Shadow [15] Endoh, S. Aircraft Collision Models. Department of
can achieve the TLS set forth by the FAA. We recommend Aeronautics and Astronautics, Massachusetts Institute of
Technology, Cambridge, MA. 1982.
all RQ-7B Shadows be equipped with this sensor.
[16] Chamlaibern, Lyle, Christopher Geyer, and Sanjiv Singh.
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