# A Review of the Operational Use of UAS in Public Safety Emergency Incidents

Hunter M. Ray  Department of Aerospace Engineering
University of Colorado Boulder
Boulder Emergency Squad
Boulder, Colorado, USA
<EMAIL_ADDRESS>Capt. Ryan Singer  Boulder Emergency Squad
Boulder, Colorado, USA
<EMAIL_ADDRESS>Nisar Ahmed  Department of Aerospace Engineering
University of Colorado Boulder
Boulder, Colorado, USA
<EMAIL_ADDRESS>
###### Abstract

The domain of public safety in the form of search & rescue, wildland
firefighting, structure firefighting, and law enforcement operations have
drawn great interest in the field of aerospace engineering, human-robot
teaming, autonomous systems, and robotics. However, a divergence exists in the
assumptions made in research and how state-of-the-art technologies may
realistically transition into an operational capacity. To aid in the alignment
between researchers, technologists, and end users, we aim to provide
perspective on how small Uncrewed Aerial Systems (sUAS) have been applied in
114 real world incidents as part of a technical rescue team from 2016 to 2021.
We highlight the main applications, integration, tasks, and challenges of
employing UAS within five primary use cases including searches, evidence
collection, SWAT, wildland firefighting, and structure firefighting. Within
these use cases, key incidents are featured that provide perspective on the
evolving and dynamic nature of UAS tasking during an operation. Finally, we
highlight key technical directions for improving the utilization and
efficiency of employing aerial technology in all emergency types.

###### Index Terms:

Human-Robot Interaction, sUAS, UAS, Public Safety, Search and Rescue,
Autonomous Systems

##  I Introduction

The increasing capability, decreasing costs, and ease of use of Uncrewed
Aerial Systems (UAS) have led to the growing adoption of these aircraft by
emergency services engaged in public safety. Public safety incidents include
operations conducted under the broad banner of firefighters, emergency medical
services (EMS), law enforcement, and other technical rescue services. The
dynamic, uncertain environments inherent in the response to an emergency
challenges the capabilities of these highly flexible platforms, which have
continued to prove their worth in assisting first responders. These incidents,
especially search and rescue, are also the subject of significant research
within the field of autonomous systems [1], human-machine interaction [2],
manned-unmanned teaming [3], controls [4], and human factors [5]. This is due
to the fact that analyzing and applying systems to the field of emergency
response parallels and compliments interactions found in other industries
including defense, planetary exploration, medicine, and personal robotics.
However, many researchers and engineers do not have a strong grasp of how
robotic platforms, such as UAS, are currently employed within these
environments, leading to a divergence between the research & development of
advanced capabilities and their realistic potential for integration with first
responders. The objective of this paper is to provide context and awareness
for how UAS have been integrated within a technical rescue team in Boulder
County, Colorado over the past five years and the methods by which they have
been employed on a range of emergency incidents. We hope that this information
can be used to guide further research and aid in the implementation of
advanced capabilities with end users.

Figure 1: Map of all analyzed calls performed in and near the diverse terrain
found across Boulder County. Credit: D4H

This paper analyzes 114 calls completed by the Boulder Emergency Squad (BES)
in which UAS were utilized from April 2016 to December 2021. Figure 1 displays
the variety of locations and associated terrain where these calls took place.
While other papers have covered specific implementations of UAS in one or two
active disaster zones [6][7][8][9][10] or field trials [11] [12], we present a
unique overview of a wide range of deployments in real-world incidents.

All of the incidents described here have been apart of a deployment with BES.
BES is a 501.c.3 non-profit organization founded over 60 years ago for the
preservation of life and property in Boulder County. BES provides a variety of
technical rescue services to the County including dive rescue, swiftwater
rescue, advanced extrication, rope rescue, wildland firefighting, urban search
and rescue, UAS, and wide area search. This allows research conducted with BES
to be evaluated over a wide variety of services and in both the rugged
mountains and expansive plains found across the County, as shown in Figure 1.
Regarding UAS specific activities, BES provides UAS services for 21 different
fire departments and 4 different law enforcement agencies in Boulder County.
This includes deploying UAS in support of wildland fires, search and rescue
operations, hazardous materials spills, SWAT and bomb related threats, and in
the case of large-scale human or natural caused disasters. Currently, BES
operates a fleet of 5+ aircraft with a variety of mission specific functions.
Aircraft are operated by FAA Part 107 licensed remote pilots who receive
continual training to improve their deployment of UAS and their effectiveness
while on a mission.

We draw upon our own experiences as first responders, detailed logs, and
interviews from fellow rescuers to synthesize the interactions found across
diverse incidents. As researchers, we also provide a unique viewpoint on
potential avenues for improving the integration, utilization, and
effectiveness of UAS flight teams. From a regulatory and training standpoints,
improved integration includes updated regulations and training to enable
beyond visual line of sight operations and improved coordination with manned
aircraft. From a research perspective, we note that current autonomous
functions are insufficient to dynamic situations and future development
necessitates a focus on making control more intuitive and flexible to reduce
the number of operators required to field a single platform, as well as
increase operator mobility and situational awareness.

The rest of the paper is organized as follows. Section II discusses how flight
teams are integrated within the incident command structure, and the various
roles that are currently required to field aerial platforms. Section III
defines the specific hardware and vehicles used to support UAS activities on
incidents. Section IV breaks down the surveyed incidents into five categories
including search, evidence collection, special weapons and tactics (SWAT),
wildland firefighting, and structure firefighting. Section V provides two
detailed reports of notable incidents, including a wildland fire, and a
missing person search. Section VI discusses opportunities for technological
improvements of UAS flight teams. Finally, Section VII concludes the paper
with primary takeaways.

##  II Team Structure

Communication often presents the weakest link in any incident response. It is
therefore vital that researchers understand systems of communication and
coordination in public safety incidents to successfully develop technologies
for responders. New technologies, such as autonomous capabilities, need to
seamlessly integrate, as opposed to heavily modifying, the command structures
to be successfully adopted. It’s important that proposed functions should
address where the feature would be integrated, and if not, how the
organizational structure should be modified to account for it. The following
describes standards for the Incident Command System (ICS) defined by the
National Emergency Management Systems [13], as well as UAS specific leadership
structures devised and implemented by BES.

Figure 2: Command hierarchy implemented during UAS incidents, with flight team
components highlighted.

###  II-A The Place of UAS within the Incident Command System

Responders assisting in the direction and pilotage of UAS, and the
dissemination of their data products, integrate within the command structure
established during an incident. On emergency incidents, personnel establish
themselves in accordance with the guidelines of the Incident Command System
(ICS), which provides a modular, top-down framework detailing how incident
response can be organized at all levels of government. An example ICS
structure with a UAS focus is shown in Figure 2. Different functions can be
stood-up by multiple people or single individuals as the incident evolves. At
the top of the structure sits the Incident Commander (IC), who maintains
authority of the organization, sets the overall objectives, and defines the
priorities. Below the IC, there can be up to four specialized sections
including: Operations, which manages the tactical response; Planning, which
collects and disseminates intelligence, and plans operations; Logistics, which
provides all necessary services to incident personnel; and Finance, which
assists in financial aspects of the incident. The ICS structure allows for
modular expansion or contraction of each of these sections’ responsibilities
as the IC deems fit for the particular response. On smaller incidents, such as
a small house fire, the IC may fulfill all of the sections’ responsibilities
themselves. Conversely, a widespread wildland fire may have multiple ICs and
section Chiefs in all branches who alternate to maintain command throughout
the incident.

UAS activities take place within the Operations section as part of the Air
Group. Within Operations, each specialty will have an established functional
supervisor. For example, a complex water rescue may have a Water Group
Supervisor, Ropes Supervisor, Medical Supervisor, and Air Group Supervisor who
all report to the Operations Chief. The Air Group Supervisor coordinates the
aerial activities, such as coordinating helicopter evacuations or UAS
operations, within the context of the incident by collaborating with the
Operations Chief and other specialty supervisors. They define and prioritize
the operational plan, coordinate with other agencies, obtain airspace
authorizations, and ensure the safety of involved aircraft.

The Flight Controller takes assignments from the Air Group Supervisor and
disseminates plans to the respective flight team members. The Flight
Controller orchestrates the details of the operation by coordinating available
air assets within the defined airspace, including defining landings zones, and
managing takeoffs and landings. For example, if the Supervisor assigns the
task of maintaining visual coverage of a portion of a burning building, the
Flight Controller will define the number of aircraft required and coordinate
their hand-off on station as batteries are swapped and charged.

Reporting to the Flight Controller include the individual flight teams, a UAS
Specialist, and Data Specialist. A flight team is led by the Pilot-in-Command
(PIC), who must maintain relevant flight qualifications, such as a FAA Part
107 certification. They may be assisted by a visual observer, who keeps the
aircraft within line of sight at all times (this can also be done by the PIC
themselves), and a scribe, who maintains a record of takeoff & landing times
and battery levels. Recording battery levels allows all resources to be
accounted for, which is especially important on extended incidents, and for
long-term maintenance purposes. A UAS Specialist assists in changing aircraft
configurations, marking landing zones, and maintaining connectivity of data
products as they’re disseminated across the command structure. Finally, a data
specialist reviews real time data, processes imagery, and stores relevant
flight data. While in theory every role could be filled by a specific
individual, the nature of the responsibilities allow an individual to
concurrently fill multiple roles.

Figure 3: The SARCOM mobile command vehicle is based on an all-terrain chassis
that enables access to remote corners of Boulder County.

Figure 4: The interior of the SARCOM vehicle provides an integrated center for
directing operations, charging aircraft batteries, and disseminating data
products across the command chain.

##  III Hardware

BES started providing UAS service in 2016 with a DJI Phantom 2 UAS. Since
then, the fleet has grown to over five aircraft from the DJI family including
Mavic, Mavic Advanced, and M210. Purchased in 2017, a DJI M210 increased the
squad’s utilization of UAS in adverse conditions, such as higher sustained
winds of up to 32.8ft/s (10m/s), at night with a FLIR camera, and new
situations with increased payload capacity. This aircraft was recently
configured with a payload delivery system, which has yet to be utilized in an
operational environment. The Mavic series of aircraft boast a top speed of
45mph (72kph), with a flight time of 25-30 minutes depending on its
configuration and how the aircraft is flown. The Mavic Advanced have a listed
range of 6 miles (10km), but they are rarely flown at this distance in
practice. These aircraft also include an IR camera, which can surpass the
capabilities of the older M-210 hardware. Looking forward, the primary
considerations in aircraft selection included the ability to meet mission
requirements, ease of use, logistical support, and cost. A future enterprise
platform will likely be a hybrid-quadcopter design, whose long endurance and
familiar flight characteristics enable it to expand upon current operational
needs.

Maintaining a fleet of aircraft allows platforms to be spread across more
vehicles and ensures that UAS are available on all incidents. However, more
aircraft require the maintenance and repair of sufficient spare batteries for
long operations. The addition of rapid battery chargers that can
simultaneously charge four batteries to 90% in 30 minutes allows field teams
to quickly swap battery packs prior to retasking.

Inaugurated in July 2017, the BES Search and Rescue Communications (SARCOM)
mobile command vehicle enables integrated and enduring UAS services to a
variety of incident types. Shown in Figure 3, it is built off a Ford F-550 XLT
pickup chassis, allowing the vehicle to be rugged enough to reach incident
locations along the narrow, unpaved roads found across much of the County. The
walk-in passenger box, shown in Figure 4, contains a variety of computers,
monitors, and a printer to aid in the planning and command of incidents. It
also carries a complement of communications equipment including VHF radio, 800
Mhz radio, WiFi antennas, VHF aircraft band radios, and LTE connectivity.
Working alongside UAS, the SARCOM enables continuous A/V streaming and data
dissemination across the command chain. Additionally, the 7KW onboard
generator allows for concurrent charging of UAS batteries, video streaming &
display, and indoor climate control.

##  IV Incident Types

UAS provides a flexible platform to assist in a wide variety of incident
types. The following section provides a high-level overview of the five
specific types of incidents where UAS have been utilized. Figure 5 details the
114 UAS-involved incidents over the last five years from 2016-2021, which have
been broken down into Search, Evidence Collection, Special Weapons and Tactics
(SWAT), Wildland Fire, and Structure Fire. Each of these instances
incorporates unique tactics and requirements for integration of the flight
teams and dissemination of UAS data products across the command chain.

Figure 5: Breakdown of reviewed UAS calls by incident type.

Search incidents involve the localization of missing persons or evidence in
urban, sub-urban, and natural environments. During a search, flight teams are
assigned segments of the operational area to cover with their aircraft to look
for the target of interest. These areas are usually divided along terrestrial
boundaries such as fence lines, power lines, ridges, bodies of water, or
forests. UAS operators and their flight team are tasked with monitoring video
feeds, looking for the potential target of interest or possible clues leading
to their discovery, such as clothing. The diverse types of possible evidence,
significant obstructions, such as looking through trees, and limited detail
available over remote video feeds complicate the automation of this task. As
an area is searched, aircraft will be able to fly anywhere from a few hundred
feet to several miles of the pilot, if line-of-sight and weather conditions
permit. However, flying at a long distance and low altitude over rugged
terrain presents a significant challenge, especially when a pilot must
concurrently scan the video and pilot the aircraft. In these situations, the
UAS data specialist assists the pilot in searching the video feeds, as shown
in Figure 6. Aircraft noise can also play a role in mission success as one
missing person reported that the aircraft noise roused them sufficiently to
call for help. Alternatively, while assisting law enforcement on a fugitive
search at night, aircraft noise alerted the suspect to the ongoing search,
potentially leading to their escape. In a separate incident, the noise was
reported to have pinned down pursued subjects in a ditch as they believed they
could easily be seen, which led to their arrest when located by a K9 team.
Automated functions available on DJI hardware, including lawnmower search
patterns and waypoint navigation, are rarely used during searches due to their
limited applicability and long setup time. The strict geometrical boundaries
required for lawnmower patterns doesn’t effectively meet the needs of the
incident as areas assigned to flight teams often include diverse terrain
types, some of which may require more direct investigation than others. For
example, a person is more likely to be sheltering in a ditch than the nearby
field, and these different environments require unique needs in terms of
vehicle speed and perspectives to reliably clear them. Furthermore, changing
terrain heights in the mountains leads to the need for a dynamic above ground
level (AGL) flight altitude, which current automation cannot effectively
support.

Figure 6: During searches, one person is often tasked with supervising the
video feed for possible evidence, sometimes inside the SARCOM vehicle.

Evidence collection involves taking photographs or videos of a crime scene, an
inactive fire location, or accident. Utilization of UAS provides multiple
perspectives to improve context, which can be especially helpful during
investigations. One or two flights by the aircraft are often sufficient to
collect the required evidence, gathering an overhead view as shown in Figure
7. In these operations, autonomous modes are often utilized to ensure full
area coverage and aid in photogrammetric reconstructions. Recognizing the
utility of UAS in these events, law enforcement have started to purchase and
utilize their own aircraft to assist in a larger number of their
investigations. Aerial imagery of fire locations can also be helpful in
understanding fire progression, especially in the initial investigation of
wildland fire origins. If the incident involves a crime, care must be taken to
ensure chain of custody of the SD card from pilot-in-command to law
enforcement.

Figure 7: UAS provide a unique perspective and critical evidence when
reconstructing accident scenes.

BES maintains a long history of working with law enforcement and SWAT teams on
investigations, raids, and other types of security operations. In particular,
UAS visual and IR cameras have become increasingly valuable in assisting
officers in dangerous incidents including active shooters, barricaded
subjects, warrant service, and VIP security. The primary mission of UAS during
these encounters involves the improvement of situational awareness, which can
manifest in a number of ways. If the hot zone is a known location, multiple
aircraft can be used to provide continuous 360° coverage of the area. During a
tragic active shooter incident at a local supermarket in Boulder, at least
four aircraft from multiple agencies were used to maintain video on all
building sides, during which temporary requests for detailed investigations
were also made via the command structure. UAS have also been used to follow
advancing officers and armored vehicles, providing extra visibility for the
surrounding areas and over obstacles. In most instances, video products are
relayed to the SARCOM vehicle for local analysis by commanding officers and
dissemination, such as to SWAT officers in the hot zone. In one case, a BES
flight team rode inside an armored vehicle to safely approach the target
location and perform reconnaissance, however, the team was later required to
relocate to properly share video with command. Key challenges for flying UAS
within these incidents include maintaining LOS and aircraft control while the
aircraft is in the hot zone, prompt relay of video products to officers on the
ground, and accurate direction of aircraft by command or ground teams.

UAS employed in wildland firefighting provide value in detecting spot fires,
and aiding firefighters in situational awareness in these highly dynamic
events. Boulder County is particularly vulnerable to destructive wildfires,
notably the Calwood Fire of October 2020, and the Marshall Fire of December
2021. However, UAS are more often utilized on smaller, developing fires prior
to the engagement with larger manned aircraft, or after the climax of the
fire’s progression for targeted extinguishing. This is particularly the case
with the investigation, detection, and assistance in mitigation of spot fires
caused by lightning strikes or traveling embers from an ongoing fire. Due to
the challenging terrain, nature of the task, and weather conditions,
autonomous functions have never been used in these incidents. The primary
challenges associated with utilizing UAS to assist in wildfires include
coordination with manned aircraft, and wind. Manned aircraft are often
employed to drop water and fire retardant, which requires them to fly at low
altitudes. Previous encounters with unauthorized UAS by manned aircraft pilots
across the country have caused significant hesitancy towards the collaborative
utilization of UAS and manned aircraft. Additionally, large fires are often
fueled by high winds, which stymie the deployment of UAS, such as during the
Marshall Fire where 100mph gusts grounded all aircraft [14]. Key components to
enabling a safe response to a wildfire involve the emplacement of lookouts,
communications between personnel about developing conditions, awareness of
multiple escape routes, and knowledge of safety zones, summed up in the often
repeated acronym “LCES” [15]. UAS are poised to potentially play a role in all
of these components by embedding flight teams within ground crews, and
employing aircraft as repeaters for improved communications in mountainous
terrain.

The final type of incidents in which BES deployed UAS involved structure
fires, such as the burning of homes, businesses, and barns. Firefighters use
UAS equipped with IR cameras to detect hot zones within the remains of the
structure, and live power lines, whose detection helps firefighters direct
their suppression efforts. IR capability could be used to detect persons still
trapped within the structure, however, this has yet to be performed BES in an
active incident in Boulder County.

##  V Detailed Incident Reports

This section presents detailed after-action reports on certain notable
incidents. These narratives provide more specific context about the
interactions between flight teams, aircraft, supervisors, and ground
personnel. The objective in presenting these summaries is to demonstrate the
dynamic and evolving nature of incident response, as well as the specific
value and challenges with employing UAS.

Figure 8: Staging area and landing zone during the Coal Creek Wildfire
Incident.

Figure 9: Narrow plume of smoke captured by UAS during the Coal Creek Wildfire
Incident

###  V-A Wildland Fire, August 6, 2020

On August 6, 2020, BES was dispatched to the Coal Creek area of Boulder County
to assist a crew of wildland firefighters with an aerial survey of two spot
fires caused by lightning strikes over a remote, mountainous area. Upon
arrival to the staging area shown in Figure 8, a pilot was tasked to use their
DJI Mavic UAS as a lookout for the hand crews digging fire lines around the
first fire. Concurrently, the M210 was sent to a second spot fire over 1 mile
away from the incident command post. This aircraft also acted as a lookout for
evolving fire situations to the single firefighter who was on the ground at
the time while additional personnel accessed the remote location. During the
course of these events, a third lightning strike was reported by crews on the
fire line and the M210 was re-tasked from its initial assignment to
investigate the report. This aircraft located the smoke and growing 10ft by
10ft fire area, shown in Figure 9. Coordinates and imagery were provided to
the IC, who was able to evaluate the severity of the fire and effectively task
additional resources. As these crews mobilized, a nearby house and best access
route for firefighters were spotted with the help of the aircraft. After being
briefly grounded by a passing rain storm, the aircraft re-evaluated the fire,
which had grown to a size of 50ft by 20ft. Flight teams coordinated with
arriving firefighters by using the aircraft as a beacon to direct them to the
best access route, where they were able to quickly mitigate the fire’s spread.
As night fell, UAS were also used to direct firefighters to egress routes. The
next day, BES was dispatched to the same area to confirm the extinguishment of
the previous day’s fires. Flight teams were tasked to utilize IR cameras to
review the heat signatures of the various fires, during which crews had to be
dispatched for further mitigation with water packs. UAS also scouted the local
area to ensure no additional fires had been started.

This incident provides a case study in the substantial value that UAS add to a
remote wildfire incident, and a few challenges that were faced merit further
discussion. First, the ground crews and aircraft had difficulty locating each
other. Crews eventually used reflective surfaces to capture the attention of
the aircraft, however this points to the need for more effective methods for
collaboration between aerial and mobile ground teams. Second, the location of
the incident command post provided an opportunistic viewpoint from which to
fly aircraft at long distances and remain within pilots’ line of sight.
However, these expansive vantage points cannot be counted on and methods for
flying beyond visual line of sight or integrating pilots within firefighter
crews should be further explored.

###  V-B Search for Missing Person, November 6, 2020

Figure 10: A map of the South Boulder Mesa, which was searched during the
November 6 incident. The incident command post and staging area is at the
lower right of the map. The victim’s shoe was found by a park ranger near the
top of South Boulder Peak at the upper left. Credit: SARTopo

In the evening of November 6, 2020 at 19:11, BES was dispatched to the South
Boulder Mesa trailhead to search for a missing, and possibly suicidal, hiker.
The challenging location, perceived victim mental state, and lack of sunlight
created additional urgency within this incident. This area of the county sits
at the intersection of the high plains and the foothills of the Rocky
Mountains, and is characterized by steep and sudden changes in elevation.
Within a horizontal distance of 0.7 miles (1.1km) the mountains in this area
rise by over 2000ft (600m). UAS were requested to search inaccessible
locations within and around the rocky crags and gullies found across the
mountain face.

Within a few hours of the incident, whose layout is described in Figure 10, a
Park Ranger found the victim’s shoe on the top of South Boulder Peak. However,
the 2.5 mile (3.9km) distance from the trailhead to mountain peak created
significant challenges towards maintaining communications and LOS with the
aircraft, which required the deployment of mobile flight teams onto mountain
trails. The only platforms currently in service by the rescue team at this
time was the DJI Mavic 210, which, due to its bulk and size, was not easily
portable up narrow trails. A utility task vehicle (UTV) was used to shuttle a
flight team up a wide path to a remote launch location that was considered to
have clear LOS towards the peak. To direct search efforts, contact with the
ranger was attempted and finally made after she shined her flashlight in its
general direction. However, the aircraft was still approximately 2000ft (600m)
away. While this distance could have been effective for searching in the
daylight with the aircraft’s 30x optical zoom camera, the FLIR camera
available aboard the aircraft couldn’t accurately resolve detail in the cliffs
at such a distance. During the search, a possible victim was sighted near the
aircraft, however could not be confirmed from the air. Being at an altitude of
approximately 1600ft (500m) above the launch point, software limitations
prevented any further altitude increases, despite the peak being 430ft (130m)
higher. The lack of effective launch positions, potential victim sighting by
the ranger, and incoming inclement weather led to the conclusion of aerial
operations. Unfortunately, the victim succumbed to their injuries.

While UAS should have added value in this type of incident, a number of
challenges hindered more effective application. Particularly notable are the
difficulties faced with employing UAS in remote, mountainous environments
without clear access or lines of sight to the area of operations. The large
horizontal and vertical distances from landing zone to the search area also
burdened the battery capacity, leaving the aircraft little time on station
once it reached the search area. Improving flight teams’ mobility, with
respect to equipment portability and control of the aircraft, could have
enabled a landing zone closer to the search area, or allowed the aircraft to
be controlled from more rugged areas with better lines of sight throughout the
search.

##  VI Discussion

As we’ve shown, UAS provide substantial value in assisting first responders in
a variety of emergency situations. We conclude with a discussion of the
perceived limitations in current technology, potential avenues for further
exploration, as well as the integration of UAS in novel emergency types. UAS
technology and their integration with incident responses are currently limited
by the requirement for line-of-sight flying, the lack of integration with
manned aircraft, the static and focused nature of current piloting modes, and
the lack of reliable computer vision.

Pilots operating under FAA Part 107 certification require their aircraft to be
in their line of sight at all times. While the technology can usually be
operated safely beyond visual line-of-sight (BVLOS), the lack of effective
vantage points, such as that found during the Coal Creek Fires, can
substantially mitigate the effective range of UAS in most environments.
However, BVLOS operations can also challenge the connectivity of operators to
the UAS, necessitating resilient and autonomous contingency functions.
Regulators working with UAS operators should develop training and update
regulations to enable safe BVLOS flying, including drawing from the experience
of military operators. Further work should also consider how UAS should be
integrated with manned aircraft during incidents, especially with respect to
wildland firefighting. Utilizing GPS to localize UAS positions on incidents
enables supervisors to coordinate and delineate airspace between platforms
with sufficient horizontal and vertical safety margins. Ongoing work in
automated collision avoidance systems for UAS, such as ACAS-Xu [16], augment
GPS localization with other collision avoidance systems, such as ADS-B, can
also assist pilots with ensuring the safety of the involved aircraft.

A major hindrance to more widespread utilization and effectiveness of UAS in
emergency responses is the burden placed upon the pilot for maintaining
control and directing the attention of the aircraft’s sensors. Pilots
currently operate fielded UAS using sticks for flight control and a series of
wheels, or a touchscreen to direct the camera’s attention. This type of
control requires the operator to be completely stationary to focus on the task
at hand, limiting their situational awareness and mobility. To support the
pilot in their task, new roles, including the flight controller and data
specialist, need to be created to ensure that their activities are well
coordinated and their information is properly disseminated and analyzed. The
multiple personnel required to support even a single aircraft highlights the
potential challenges when considering the integration of multiple autonomous
aircraft (i.e. swarms) for these types of incidents. As we’ve shown, UAS are
utilized in a wide range of dynamic situations where aircraft can be given
diverse and changing task assignments. Development of autonomous functions
should focus on enabling pilots to communicate intentions in an intuitive
manner irrespective of the particular nature of the incident. Integration of
new technologies within these environments can apply co-active design
principles that consider the interdependent nature of specific tasks and
respectively leverage and compliment the rescuer and platform capabilities
[17]. Autonomous functions such as optimal path planning for search & rescue
can only be achieved if all information can be effectively quantified for the
algorithm, which necessitates the burdensome incorporation of contextual
information from a particular incident. The objective of autonomous modes
should not be to obviate the need for a rescuer, but instead to take over
basic piloting tasks to improve an operator’s mobility and situational
awareness, and reduce their workload. Enabling the intuitive direction of UAS
in a manner that integrates the aircraft’s capabilities within the team
presents the greatest opportunity for enabling flight teams to respond to and
adapt to dynamic situations. Methods such as [18], which employ a POMDP
algorithm aboard a UAS to track wildfire growth, are promising, but need
methods to incorporate larger contextual information and constraints provided
by operators to have a chance of being employed in active incidents.

To a limited capacity, some autonomous functions are employed by operators on
all incidents, and are noted for their integration within the primary “manual”
piloting mode. These can be broken up into functions for information synthesis
and contingency flight modes. With respect to information synthesis,
particularly notable is a battery life estimate, which take into account the
current distance from the landing zone to the aircraft’s current position to
give an estimated remaining flight time. The associated metrics and audio
warning features help the operator stay aware of their aircraft’s status and
the aircraft can even take control when the battery is at critical levels.
Additional autonomous functions that synthesize flight information and detect
upcoming failures, such as component fault detection [19], can be readily
integrated into operational systems as they can be easily ignored or utilized
by pilots without issue. The sole contingency flight mode available on DJI
hardware is a return-to-home function, which is triggered when the battery is
critically low, the aircraft suffers from a connection failure, or at the
operator’s request. Therefore, setting the return-to-home altitude is a
critical component within the pre-flight checklist. It was observed that this
mode was activated by pilots on a number of incidents even when the aircraft
was operating effectively to aid in returning to the landing zone.
Incorporating more sophisticated contingency flight modes that incorporate
active obstacle avoidance and dynamic terrain will be critical towards
enabling reliable BVLOS operations. However, ensuring that operators reliably
trust the performance of these flight modes is another important aspect of
their integration.

Figure 11: Current methods of UAS pilotage require static pilots fully engaged
in their tasks.

Incorporating computer vision into video stream analysis of UAS derived video
products presents another opportunity for further research. During a search
with UAS, a single person may be required to supervise a video feed to check
for evidence of the missing individual. Computer vision cannot be entirely
relied upon due to the challenging perspectives required in most operations,
and myriad of objects that may be desired. However, a limited application of
computer vision could query an operator for investigation of perceived
anomalies in IR signatures, colors, patterns, or shapes.

The flexible nature of UAS platforms allows potential for application in novel
regimes and implementations. For example, a swiftwater search and rescue
operation may entail a challenging exploration of a creek or riverway for
possible evidence of the missing persons. While heavy undergrowth on the banks
and dangerous rapids can present significant obstacles for ground and water
teams, these incidents present a ripe opportunity for UAS to be leveraged for
the search. UAS could also be used to deliver supplies and aid to stranded
people, assist in avalanche rescue, and act as communication relays in remote
areas. Additionally, novel modalities of integration could include deployable
fixed-wing aircraft that can launch from a centralized location to provide
earlier incident evaluations, similar to that being done by the Chula Vista
Police department with quadcopter UAS[20].

##  VII Conclusion

It’s clear that UAS are increasingly providing value to first responders on
diverse incident types. This paper demonstrates the various methods and
structures by which UAS assist first responders in diverse public safety
emergency incidents. An overview of the command structure by which flights are
coordinated was presented and call attention to the multiple personnel often
required to manage a single airborne platform. We reviewed 114 incidents where
UAS were utilized to assist with searches, evidence collection, wildland
firefighting, structure firefighting, and SWAT operations. Notable incidents
that merit detailed recounting were highlighted to provide perspective on the
dynamic nature of a particular response. Finally, current technological and
regulatory limitations were discussed, and recommendations for areas of
additional study were provided.

The integration of UAS with first responders allows a unique perspective in
the study of human-machine interaction and manned-unmanned teaming. In the
near term, researchers should focus less on making highly sophisticated “out-
of-the-box” autonomy that immediately performs with minimal supervision, which
leads to brittle and unreliable performance. Instead, UAS technology
development should aim towards enabling lower-level decision-making and
perception features that allow for varying levels of integrated autonomy,
operator trust, and aircraft control with minimal training. Within incidents,
human-centered coordination of operations remains key, since the context and
dynamics of an incident can vary drastically within and between missions for
the same set of vehicles and operators. Aligning the needs of these end users
with ongoing research thrusts will enable greater utilization of developed
capabilities in public safety emergencies and other applications of human-
robot teaming in complex, dynamic, and uncertain environments.

## Acknowledgment

The authors would like to thank the members of BES for their helpful and
insightful contributions.

## References

  * [1] Luke Burks  “Active Collaborative Planning and Sensing in Human-Robot Teams”  Boulder, Colorado: University of Colorado Boulder, 2020
  * [2] Robin R Murphy  “Human-robot interaction in rescue robotics”  In _IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews)_ 34.2 IEEE, 2004, pp. 138–153
  * [3] Huadong Wang et al.  “Scalable target detection for large robot teams”  In _Proceedings of the 6th international conference on Human-robot interaction_ , 2011, pp. 363–370
  * [4] Yugang Liu and Goldie Nejat  “Robotic urban search and rescue: A survey from the control perspective”  In _Journal of Intelligent & Robotic Systems_ 72.2 Springer, 2013, pp. 147–165
  * [5] Jessie Chen  “Advances in Human Factors in Robots and Unmanned Systems”  In _AHFE International Conference on Human Factors in Robots and Unmanned Systems. Florida: AHFE_ , 2017  Springer
  * [6] Robin Murphy et al.  “Two case studies and gaps analysis of flood assessment for emergency management with small unmanned aerial systems”  In _2016 IEEE International Symposium on Safety, Security, and Rescue Robotics (SSRR)_ , 2016, pp. 54–61  DOI: 10.1109/SSRR.2016.7784277
  * [7] Hartmut Surmann, Dominik Slomma, Stefan Grobelny and Robert Grafe  “Deployment of Aerial Robots after a major fire of an industrial hall with hazardous substances, a report”  In _2021 IEEE International Symposium on Safety, Security, and Rescue Robotics (SSRR)_ , 2021, pp. 40–47  DOI: 10.1109/SSRR53300.2021.9597677
  * [8] Ranjana K Mehta, Joseph Nuamah, S. Camille Peres and Robin R. Murphy  “Field Methods to Quantify Emergency Responder Fatigue: Lessons Learned from sUAS Deployment at the 2018 Kilauea Volcano Eruption”  In _IISE Transactions on Occupational Ergonomics and Human Factors_ 8.3, 2020, pp. 166–174  URL: https://doi.org/10.1080/24725838.2020.1855272
  * [9] Robin R. Murphy et al.  “Use of a Small Unmanned Aerial System for the SR-530 Mudslide Incident near Oso, Washington”  In _Journal of Field Robotics_ 33.4, 2016, pp. 476–488  DOI: 10.1002/rob.21586
  * [10] Geert-Jan M Kruijff et al.  “Rescue robots at earthquake-hit Mirandola, Italy: A field report”  In _2012 IEEE international symposium on safety, security, and rescue robotics (SSRR)_ , 2012, pp. 1–8  IEEE
  * [11] S. Karma et al.  “Use of unmanned vehicles in search and rescue operations in forest fires: Advantages and limitations observed in a field trial”  In _International Journal of Disaster Risk Reduction_ 13, 2015, pp. 307–312  DOI: 10.1016/j.ijdrr.2015.07.009
  * [12] Michael A. Goodrich et al.  “Towards using Unmanned Aerial Vehicles (UAVs) in Wilderness Search and Rescue: Lessons from field trials”  In _Interaction Studies. Social Behaviour and Communication in Biological and Artificial Systems_ 10.3, 2009, pp. 453–478  DOI: 10.1075/is.10.3.08goo
  * [13] “National Incident Management System”, 2017  Federal Emergency Management Agency  URL: https://www.fema.gov/sites/default/files/2020-07/fema_nims_doctrine-2017.pdf
  * [14] Blair Miller  “National Weather Service analysis identifies factors that caused Marshall Fire to spread so quickly”  In _The Denver Channel_ , 2022  URL: https://www.thedenverchannel.com/news/marshall-fire/national-weather-service-analysis-identifies-factors-that-caused-marshall-fire-to-spread-so-quickly
  * [15] Paul Gleason  “Lookouts, Communication, Escape Routes and Safety Zones, “LCES””, Online, 1991  URL: https://www.nwcg.gov/sites/default/files/wfldp/docs/lces-gleason.pdf
  * [16] Michael P Owen et al.  “ACAS Xu: Integrated collision avoidance and detect and avoid capability for UAS”  In _2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC)_ , 2019, pp. 1–10  IEEE
  * [17] Matthew Johnson et al.  “Coactive design: Designing support for interdependence in joint activity”  In _Journal of Human-Robot Interaction_ 3.1 Journal of Human-Robot Interaction Steering Committee, 2014, pp. 43–69
  * [18] Kyle D Julian and Mykel J Kochenderfer  “Distributed wildfire surveillance with autonomous aircraft using deep reinforcement learning”  In _Journal of Guidance, Control, and Dynamics_ 42.8 American Institute of AeronauticsAstronautics, 2019, pp. 1768–1778
  * [19] Elgiz Baskaya, Murat Bronz and Daniel Delahaye  “Fault detection & diagnosis for small UAVs via machine learning”  In _2017 IEEE/AIAA 36th Digital Avionics Systems Conference (DASC)_ , 2017, pp. 1–6  DOI: 10.1109/DASC.2017.8102037
  * [20] Chula Vista Police Department  “Drones as First Responder: The Future of Public Safety”, Online, 2022  URL: https://www.chulavistaca.gov/home/showpublisheddocument/19749/637084636048200000