Drones for Civil Defense: A Case Study in the City of Niter

Carlos Alberto Malcher Bastos

, Diego Passos

2,4 a

, Walace Medeiros Barbosa

Yuri Sisino Dos Santos Felipe

, Thais Belloti Loureiro

, Gilvane Dos Santos Dias

and Fernanda G. O. Passos

1,3 b

Engineering School, Universidade Federal Fluminense, Niter

oi, Brazil

Institute of Computing, Universidade Federal Fluminense, Niter

oi, Brazil

Atl

antica Instituto Universit

ario, Oeiras, Portugal

DEETC, Instituto Superior de Engenharia de Lisboa – ISEL, Lisbon, Portugal

Civil Defense Department, City Hall of Niter

oi, Niter

oi, Brazil

Keywords:

Drones, Unmanned Aerial Vehicle, Smart Cities, Civil Defense.

Abstract:

Nowadays, drones or Unmanned Aerial Vehicles (UAVs) are employed for several purposes such as deliver-

ing products, spreading pesticides on crops, providing internet access to remote areas, and taking videos and

photos for entertainment. In the context of smart cities it is not different. Some cities have adopted drones for

a number of important tasks, such as surveillance, trafﬁc monitoring, and disaster management. Indeed, their

ability of reaching difﬁcult places and the possibility of carrying different sensors and actuators make those

devices very ﬂexible tools that can adapt to several use cases. Nevertheless, there are still obstacles — techni-

cal, regulatory or even social — that can hinder the applicability of drones to certain tasks. In this work, we

report and analyze the use of drones by the Civil Defense Ofﬁce of the city of Niter

oi, Brazil, as a case study.

In recent years, the ofﬁce has been increasingly adopting drones for automatizing or simplifying a number

of processes with varying degrees of success, and intend to adopt information and knowledge management

systems to support and optimize their use. We present a list of the current drone-aided tasks performed by

the ofﬁce, as well some potential applications that are not yet feasible for one reason or another. We further

analyze those obstacles and discuss what can be done to address them.

1 INTRODUCTION

Popularly known as drones, Unmanned Aerial Vehi-

cles (UAVs) are ﬂying devices that can be used for

a variety of purposes due to their mobility and abil-

ity to collect data from a region of ﬂight. Either au-

tonomously or controlled by a pilot, drones can carry

out remote missions replacing the human presence,

which can either enable activities that were otherwise

impossible — e.g., due to the impossibility of reach-

ing a certain region of interest — or, at least, mini-

mize risks and accelerate the delivery of services and

goods. For a few examples, drones have been used

for monitoring volcanic environments (de Moor et al.,

2019) and, famously, by the Amazon prime air ser-

vice (Shavarani et al., 2018).

https://orcid.org/0000-0002-9707-1176

https://orcid.org/0000-0002-6647-9822

Those two examples help illustrate the wide range

of activities that can be enabled or aided by the use

of drones. This ﬂexibility can be explained by three

particular characteristics of these devices: their abil-

ity to ﬂy — thus allowing highly efﬁcient and effec-

tive mobility —, as well as their capacity of carry-

ing different types of loads and their intrinsic com-

munication functionalities. More speciﬁcally, drones

can carry both sensors and actuators which can be

accessed remotely using the drone’s communication

channel with the ground station. While recreational

drones often carry cameras for video or photogra-

phy, other types of payload can be added, such as

smoke detectors, temperature sensors, speakers, or

headlights. Therefore, armed with the right payload,

drones can be adapted to countless activities. This

has popularized their usage in several different ﬁelds,

including agriculture, entertainment, industry, mili-

tary, surveillance, maritime rescue and security in-

Bastos, C., Passos, D., Barbosa, W., Felipe, Y., Loureiro, T., Dias, G. and Passos, F.

Drones for Civil Defense: A Case Study in the City of Niterói.

DOI: 10.5220/0011552800003335

In Proceedings of the 14th International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management (IC3K 2022) - Volume 3: KMIS, pages 72-82

ISBN: 978-989-758-614-9; ISSN: 2184-3228

spection of construction sites (Hassanalian and Ab-

delkeﬁ, 2017; Ayamga et al., 2021).

In the context of smart cities, drone usages may

be roughly divided into three broad categories: mon-

itoring (i.e., gathering data by means of certain types

of sensors), actuation (i.e., performing actions onto

the environment) and services (i.e., serving as a com-

plimentary infrastructure). As examples, UAVs can

be used for monitoring trafﬁc and pollution, detect-

ing accidents and wildﬁre, improving communication

network connectivity, and assisting city surveillance

structures (Alsamhi et al., 2019; Kim et al., 2018).

While the aforementioned activities are common

for most cities around the world, each region has its

own set of particular issues. Niter

oi is a Brazilian

city of about 500 thousand inhabitants — a medium-

sized city by Brazilian standards —, located in the

metropolitan region of the state of Rio de Janeiro. It

is considered an ongoing smart city, with initiatives

currently under implementation through the Applied

Projects Development Program (PDPA) (Reis et al.,

2021), a partnership between the City Hall and Uni-

versidade Federal Fluminense (UFF).

Even before the PDPA, the City Hall of Niter

oi al-

ready used drones for a number of purposes. More

speciﬁcally, in recent years, its Civil Defense Ofﬁce

has been using drones in some of the services it pro-

vides to the local population. Indeed, the expertise

developed by Niter

oi’s Civil Defense in the usage of

drones for the well-being of the population has be-

come a reference in Brazil, and its teams are often

deployed to help disaster-response missions around

the country, as we will detail in the rest of this paper.

Aside from those disaster-response missions, this of-

ﬁce also provides efforts to prevent and protect the cit-

izens from natural hazards, as ﬂoods, landslides and

wildﬁres. In a nutshell, it works with both routine and

emergency operations in order to prevent, mitigate,

evacuate and/or recover from disasters. In that sense,

drones are used to inspect regions — either where a

disaster has taken place or that have a potential for

a natural disaster —, seeking to capture information

that will help carry out rescue operations and avoid

further damage.

This work is one of the ﬁrst results of DroNit, one

of the PDPA projects, which aims to optimize the use

of drones in the Civil Defense Ofﬁce by applying,

among other techniques, information and knowledge

management. The paper has the speciﬁc objective of

reporting the practical experience of Niter

oi’s Civil

Defense Ofﬁce on the use of drones. Other aspects

will be the subject of further work. We list and de-

scribe a number of current drone-aided activities per-

formed by the ofﬁce, discussing how the drones have

enabled them or made them more effective. We also

highlight limitations of the currently used drones for

those tasks, pointing out the technical challenges that

hinder a more effective applicability. We further de-

scribe other activities of the Civil Defense that could

perhaps be aided by drones, but that currently not pos-

sible either for technical, regulatory or even social

reasons.

The contribution of the paper is multifold. Firstly,

it raises awareness for innovative uses of drones that

are possibly useful for other cities. Secondly, it high-

lights gaps in the current drone technology that hin-

der its usability for useful smart city applications.

Thirdly, it indicates possible research areas and open

problems regarding the usage of drones in smart

cities.

The remainder of the text is organized as fol-

lows. Section 2 reviews a number of common uses for

drones in smart cities and provides a brief overview

of the related literature. Section 3 presents our case

study of Niter

oi’s Civil Defense Ofﬁce, describing

its typical tasks that are — or could be — aided by

drones. In Section 4 we highlight the main challenges

identiﬁed with the usage of drones for the activities of

the ofﬁce and also discuss ideas for how the drones’

usefulness my be improved for the Civil Defense. Fi-

nally, Section 5 concludes the paper.

2 DRONES FOR SMART CITIES

AND CIVIL DEFENSE

Jensen (Jensen, 2016) addresses the theme of drones

and their potential applications in the area of smart

cities. In his work, he explores the connectivity is-

sues related to the use of drones in smart cities and

discusses how drones can improve their applications

such as surveillance, object detection, general pur-

pose distributed processing applications, data collec-

tion, route planning, tracking delivery, navigation and

collision prediction.

The implementation of a service based on the use

of drones requires studies in several aspects (Alsamhi

et al., 2019). One of them is to establish a physical

architecture, that is, choosing the drones, the types of

connectivity available, the types of sensors and actua-

tors, establishing ground stations for battery recharge,

and establishing maximum ﬂight time considering the

measurements that will be performed. As an exam-

ple, (Kim et al., 2018) designed a framework for the

use of multiple UAVs to cover extensive areas for

surveillance. The authors consider public and private

UAVs — public institutions and companies or citi-

zens, respectively — analyzing aspects such as bat-

Drones for Civil Defense: A Case Study in the City of Niterói

tery limitation, delivery of supplies (e.g., medicine),

collision avoidance, global positioning, autonomous

ﬂights and connectivity using standard for vehicular

communication (IEEE 802.11p) or over LTE (Long

Term Evolution) when available in the region. Still

in this context, (Katila et al., 2017) studies scenar-

ios where drones are used to monitor a large area and

transmit video information to a remote control unit

using multiple hops. To maintain a strong connectiv-

ity between drones and the control unit, the authors

used wireless mesh networks (IEEE 802.11s) at ﬁxed

positions on the ground to increase the node redun-

dancy for routing.

Giordan et al. (Giordan et al., 2018) present a re-

view of remotely piloted aircrafts (RPAs), also known

as UAV, applied to natural hazards around the world

such as landslides, ﬂoods, earthquakes, volcanic ac-

tivity and wildﬁres. RPAs are used to collect data

from inaccessible regions typically from images from

conventional cameras, but also, in some cases, from

thermal sensors and multi-spectral cameras. These

RPA-gathered data are then georeferenced and pro-

cessed in order to provide, for instance, environmen-

tal and geological studies, mapping different active

processes at the Earth’s surface and analysis of river

channel vegetation.

More recently, Gohari et al. (Gohari et al., 2022)

systematically reviewed the literature of using drones

for monitoring and surveillance in smart cities, classi-

fying the papers into seven categories: transportation,

environment, infrastructure, object or people detec-

tion, disaster management, data collection and other.

Air pollution (environment) and trafﬁc monitoring

(transportation) are the aspects more studied in the re-

cent literature. In the disaster management category,

the main areas are human body detection, evacuation

map building, ﬁre detection, ﬁreﬁghting management

and search and rescue. They also associate the cat-

egories according to the number of UAVs (multiple

or single), type of UAV (mostly, with rotatory wings)

and the aerial sensors on board (mostly, conventional

camera).

2.1 Characterization of Drones

Because drones are used for so many different appli-

cations, several different offerings can be found on the

market with markedly different characteristics. Per-

haps the most fundamental way drones may differ is

in terms of typology, the most common being ﬁxed-

wing, single-rotor, multirotor, and ﬁxed-wing hy-

brid (Jayaweera and Hanoun, 2020). Like an airplane,

ﬁxed-wing drones have rigid wings that provide lift

whenever the aircraft moves forward. Conversely,

single- and multirotor drones have rotating vertical

propellers for lift. While ﬁxed-wing drones can

achieve much higher speeds, cover larger distances

and potentially carry substantial weight, single- and

multirotor drones have advantages in terms of maneu-

verability, allowing more controlled ﬂights and the

possibility of remaining at a relatively stable position

(which often aids in tasks involving photography or

video). In particular, multirotor drones are more sta-

ble than their single-rotor counterparts, and the num-

ber of propellers usually correlates with their load ca-

pacity (Hassanalian and Abdelkeﬁ, 2017).

Drones also vary wildly in terms of weight and

size. While consumer drones used for entertainment

can weigh as little as a few hundred grams, military

drones can weigh several hundred kilograms and be

roughly as large as some manned aircraft (Hassana-

lian and Abdelkeﬁ, 2017). Because heavier drones

require more powerful propellers, they are also usu-

ally able to transport more load.

Another important issue is autonomy. Consumer

drones in general use electrical engines powered by

batteries which offer relatively short ﬂight times.

Some larger capacity drones, however, use internal

combustion engines allowing for much larger auton-

omy.

While some drones may have a few autonomous

ﬂight capabilities (e.g., avoiding collisions, returning

home under certain conditions), the most common

mode of operation has the drone being piloted re-

motely. Thus, a reliable communication between the

drone and a ground station is fundamental. Differ-

ent radio technologies can be found in different mod-

els. Some models resort to open standards, such as

IEEE 802.11, while others may employ proprietary

radio solutions — DJI, for example, uses its own ra-

dio technology called OcuSync (Swinney and Woods,

2021). However, regardless of the particular technol-

ogy, consumer drones must generally operate under

unlicensed radio bands, alongside multiple compet-

ing devices, which may reduce communication per-

formance.

In terms of payload, consumer drones often carry

ordinary cameras for visible light, which can be used

both for aiding the pilot and for recording video or

taking photos. For more specialized applications,

multispectral cameras can be used — e.g., infrared

can be used for monitoring vegetation growth and

coverage. Thermal cameras are also useful for ﬁnd-

ing lost persons, especially under vegetation cover-

age, such as in forests. Drones equipped with a LI-

DAR can map the topography of a region and/or of

buildings. Other possibilities include sensors for tem-

perature and smoke, which can be useful for detecting

KMIS 2022 - 14th International Conference on Knowledge Management and Information Systems

Table 1: Main roles of the Civil Defense ofﬁce of Niter

oi.

Id. Role Reactive Proactive

1 Identify and map risk areas, monitor slope/hill stabilization works X

2 Inspect risk areas avoiding occupations X

3 Inspect buildings, evacuating areas of risk or vulnerable buildings X

4 Inform the population about risk areas, extreme events, protocols X

5 Perform simulated exercises X

6 Collect, distribute and control supplies in disaster situations X

7 Assess damages and losses of disaster affected areas X

8 Develop citizen awareness of disaster prevention X

9 Encourage economic and production restructuring of affected areas X

10 Train human resources for civil defense and protection actions X

11 Provide data and information to the national system X

ﬁres. Actuators can also be carried by drones. Head-

lights and loudspeakers, for example, can be used to

draw attention to the drone or to disseminate warning

messages. In agriculture, drones are often equipped

with tanks that can store liquids for irrigation or ap-

plication of pesticides. Those sensors and actuators

can either be controlled by some standalone compu-

tational device — also carried by the drone — or be

connected to the drone’s ﬂight controller so that they

can be accessed remotely by the same communication

channel used to pilot the vehicle.

3 CASE STUDY: CIVIL DEFENSE

OF NITER

In this section, we describe the main activities of the

Civil Defense Ofﬁce of the Niter

oi City Hall and how

those activities are — or could be — aided by Drones.

The information contained here is based on several in-

terviews we conducted with the personnel of the of-

ﬁce, as part of a process of understanding their needs,

as well as how their current experience with drones is

and what could be improved.

3.1 Roles and Daily Activities

The mission of the Civil Defense Ofﬁce is regulated

by a municipal law

which deﬁnes the assignments of

the civil defense and protection services to the citizens

of the city of Niter

oi.

The overall goal of a Civil Defense ofﬁce is to pro-

tect the population against natural disasters, as well

as other types of civil disturbance. This is done both

reactively — i.e., in response to particular occurrence

— and, ideally, proactively — i.e., by taking measures

Law nº 3561 published on December 18, 2020, avail-

able (in Portuguese) in http://leismunicipa.is/dvfyk.

that avoid or mitigate the occurrence of such events.

Table 1 presents the main roles of the ofﬁce and their

classiﬁcations in relation to being reactive or proac-

tive to disaster events.

This is, of course, a broad deﬁnition and, as such,

can encompass different concrete actions for ofﬁces

of different cities. Aspects such as the city’s climate

and topography, as well as cultural trends of the pop-

ulation itself, play an important role on deﬁning the

responsibilities and speciﬁc daily actions of a partic-

ular Civil Defense ofﬁce.

Niter

oi, in particular, is a coastal city with tropical

climate. Temperatures are high through most of the

year, and heavy rains and storms are frequent during

the summer. The topography is quite uneven, formed

by hills spread throughout the city area. Due to this

topography and to the population density, houses and

other types of constructions are often built on those

hills.

Unfortunately, the combination of those factors

makes mudslides a common and troubling occur-

rence. Those mudslides can destroy houses and lead

to deaths. That is especially likely for illegal con-

structions, such as houses built on unstable terrains

and without the proper permits demanded by the city

hall. Thus, this is an area of particular concern to the

Civil Defense Ofﬁce.

In order to avoid or mitigate tragedies related to

those mudslides, the ofﬁce has to constantly monitor

the city perimeter for early signs of illegal construc-

tions. It also has to monitor areas that are particularly

vulnerable to this type of event, such as hills, check-

ing the state of vegetation coverage, as well as signs

of terrain instability.

One of the tools employed by the ofﬁce for this

purpose are satellite images. Those images are re-

ceived periodically and are analyzed by technicians.

The goal is to identify and measure areas of defor-

estation, as well as possibly illegal constructions.

Drones for Civil Defense: A Case Study in the City of Niterói

Nevertheless, despite those preventive measures,

mudslides sometimes still occur. When they do, the

Civil Defense ofﬁce is also responsible for emergency

actions, such as assessing damage, helping evacuate

the affected area, helping ﬁnd survivors, as well as

making essential supplies arrive at those locations.

Because of the perennial high temperatures, natu-

ral wildﬁres are also a relatively common occurrence

that may pose threat to the population. As such, the

Civil Defense Ofﬁce is also responsible for mapping

and monitoring vulnerable areas susceptible to ﬁres,

such as the identiﬁcation of dry vegetation.

Another common threat that is often faced by

the Civil Defense Ofﬁce of Niter

oi are ﬁre balloons.

Despite being a punishable offense according to the

Brazilian law, building and releasing ﬁre balloons into

the air is still a common form of cultural expression

in several parts of Brazil. Those balloons, however,

pose a serious risk, as their paths are unpredictable —

they depend on the direction and speed of the wind

in that particular moment — and when they fall, they

can start ﬁres. Because of that, detecting, capturing

and dealing with the consequences of illegal ﬁre bal-

loons is also a concern of the Civil Defense in Niter

oi.

Aside from its duties to the population of Niter

oi,

the city’s Civil Defense Ofﬁce also collaborates with

its peers from other cities around the country. This

happens through the exchange of information among

the ofﬁces, but also possibly in the form of direct ac-

tion in situ when severe disasters take place in other

cities.

3.2 Current Use of Drones

Many of the activities described in Subsection 3.1 can

be aided by the usage of drones. Indeed, for the past

several years, the ofﬁce has been using drones for dif-

ferent purposes. The Civil Defense Ofﬁce holds a

drone operation crew trained to pilot the equipment

for preventive and emergency missions.

One such use is for complementing the analysis of

satellite images. When that analysis suggests signs of

irregular constructions, for example, the ofﬁce con-

ducts drone missions over the area in order to obtain

more detailed images to conﬁrm or dismiss on the sus-

picion.

Drones are also used for providing support dur-

ing natural disasters or wildﬁres. In this case, the de-

vices can help quickly identifying the extension of the

affected area, as well as other potentially useful in-

formation, such as available access routes for ground

crews.

3.2.1 Actions with Drones during Emergencies

The preventive work conducted by the Civil Defense

Ofﬁce is perhaps the most important because it can

avoid threats. Nevertheless, to the general popula-

tion, the actions of the ofﬁce are more apparent under

emergency situations. Incidentally, these emergencies

are currently one of the main use cases of drones by

the Civil Defense Ofﬁce of Niter

oi. Indeed, despite

its drone operation crew existing for just a few years,

it already has a signiﬁcant track record of operations

of this kind.

In 2019, for instance, a ﬁre started in a forest area

in the neighborhood of Charitas, in Niter

. While

handling the ﬁre is primarily a task of the ﬁre depart-

ment, the Civil Defense Ofﬁce provided support for

the operation. In particular, the drone operation crew

conducted survey ﬂights that allowed the response

units to visually assess the extension of the ﬁre, as

well as to identify the most critical ﬁre spots. The im-

ages of that survey also allowed the ﬁre department to

anticipate the most likely direction for the spread of

the ﬁre and to identify possible routes for the ﬁremen

to access the region.

More recently, in 2022, a team of the Civil De-

fense Ofﬁce of Niter

oi was sent to the state of Bahia

to provide support to response units of that state dur-

ing a season of severe rain storms that took place by

the end of 2021

. One of the main tasks of this team

during this event was to help assess the state of hills

and other areas under the risk of mudslides. Among

other tools, the team employed drones to obtain de-

tailed aerial footage and images that were later ana-

lyzed by geologists and engineers to pinpoint risk ar-

eas.

A month later, the nearby city of Petr

opolis was

hit by a heavy storm that cause severe damage to

the infrastructure

and killed over 150 persons. As

they did in the storms in Bahia, a team of Niter

oi’s

Civil Defense Ofﬁce collaborated with the local au-

thorities by using drones to identify areas in risk of

mudslides and constructions in risk of collapse. The

storm also caused a ﬂooding that dragged vehicles, in-

cluding two busses that were carried towards a river

and sunk. Eventually, the drone operation crew of

the Civil Defense Ofﬁce of Niter

oi was called upon

to help in the searches of missing people. By using

More details (in Portuguese): http://www.sma.niteroi.

rj.gov.br/index.php?option=com content&view=article&

id=5966:2019-08-05-19-01-40

More details: https://edition.cnn.com/2021/12/26/

americas/brazil-bahia-ﬂooding-w/index.html

More details: https://www.bbc.com/news/world-latin-

america-60401611

KMIS 2022 - 14th International Conference on Knowledge Management and Information Systems

drones, the search process became much faster, and

larger areas were covered more quickly.

Similarly, in June 2022, heavy rains caused de-

struction in several cities in the state of Pernambuco,

in the Northeast of Brazil. Once again, Niter

oi’s Civil

Defense Ofﬁce lent its expertise and performed drone

ﬂights with the objective of assessing mudslide risk

areas. It also collaborated by inspecting the state of

constructions to determine which were safe for the re-

turn of the affected families.

3.2.2 Products

The Niter

oi’s Civil Defense Ofﬁce generates products

related to their main actions in the city and services

even in other cities. These products are response to

other municipal departments about the services pro-

vided — e.g. Fire Department — and, ultimately, to

the population.

Frequently, the crews of Civil Defense use drones

to collect data in situ. From these data, several infor-

mation relevant to the incident or occurrence is gath-

ered and reported in documents (products). These

products are forwarded to the competent departments

of the City Hall so that actions can be taken to avoid

or handle the situation. These products are basically

reports that can include landslide areas, risk areas, soil

typology, affected properties and buildings and so on.

3.3 Demands of Drone Usage

Aside from the current uses described in Section 3.2,

other activities of the Civil Defense Ofﬁce of Niter

could be improved, facilitated or even enabled by the

employment of drones with suitable characteristics.

The inspection of constructions is one such activ-

ity. Currently, those inspections are done solely in

situ and, therefore, require a technician to physically

attend each building. Periodical drone surveys with

sufﬁciently detailed images could save resources by

allowing a preliminary remote evaluation of the state

of the constructions. This, in turn, may allow more

frequently inspections for each building, reducing the

risk of accidents.

Drones could also be used during events with

large concentration of people — such as concerts or

protests. A drone equipped with loud speakers could

be used to disseminate audio messages containing

safety instructions or warnings regarding emergency

situations. As a more concrete example, the city has

siren systems in several mudslide risk areas that are

activated when storms are forecast. Drones could im-

prove that by spreading the warnings in regions where

the alarm system has not yet been implemented.

Another interesting possibility is the usage of

drones for transporting essential supplies — e.g.,

medication — during rescue operations. They could

reach difﬁcult areas quickly and provide some kind of

ﬁrst response before ground crews arrive.

Even in the activities for which the ofﬁce already

uses drones, its role could be expanded for better re-

sults. For example, while the ofﬁce currently uses

drones to help identify risk areas and irregular con-

structions therein, the device’s role is secondary, as

it is used only as a means for conﬁrming or detail-

ing satellite image analysis. However, satellite im-

ages take time to obtain and sometimes are unusable

due to the presence of clouds. Thus, instead of a sim-

ple tool for conﬁrmation or detailing, drones could be

used more frequently as a primary source of the im-

ages used for this task, mitigating the aforementioned

issues.

Another example is the handling of ﬁre balloons,

especially during the times of the year in which this

practice is more common. The idea is to follow the

path of the balloon in order to guarantee that it will

ﬂy to a safe area or to anticipate the areas on which it

may fall so that a proper response can be prepared.The

ofﬁce could further mitigate the risks by trying to ac-

tively handle them. One possibility would be to use

drones to drag or direct the balloon to areas of lower

risk. Alternatively, drones could be used to take the

balloon down in a controlled manner — for example,

by using water or chemicals to cool down the bal-

loon’s heat source.

Further notice that drone ﬂights can be simulated

in anticipation to a certain mission. By exploiting

that, the Civil Defense Ofﬁce might conduct simu-

lated exercises and use ﬂight simulators to assess the

most beneﬁcial manner to deploy drones in different

situations, complementing their other teams/actions.

This would allow them to maximize the effectiveness

of the drones in real emergency situations.

4 CHALLENGES AND INSIGHTS

The activities performed by the Civil Defense Ofﬁce

of Niter

oi — surveyed in Section 3 — reveal a num-

ber of speciﬁcities that are, in many regards, differ-

ent from the most common drone uses. As such,

there are many issues identiﬁed and unique challenges

that need to be addressed, as well as lessons to be

learned from the secretariat’s experience, providing

a vast ﬁeld of research and for proposals of informa-

tion and knowledge management and development of

appropriate information systems.

Drones for Civil Defense: A Case Study in the City of Niterói

4.1 Identiﬁed Issues and Challenges

According to the drone staff of the Civil Defense Of-

ﬁce, the drones employed in their missions have a

ﬂight autonomy of approximately 15 to 20 minutes

— depending on the wind velocity and temperature

—, impairing actions that demand either long ﬂight

times or large areas to be covered. To mitigate this

issue, the drone operation crew takes several backup

batteries to the missions. Still, this relatively low au-

tonomy results in interruptions in the missions as the

drones must return to the ground station so that the

batteries can be manually replaced. Also, recharging

the depleted batteries on the ﬁeld is not always easy

or fast due to power outlets not always being available

on the site. Thus, this can be a limiting factor for the

length of the missions.

The weather is another issue. As described in Sec-

tion 3, several use cases of the Civil Defense Ofﬁce

are concerned with rain-related emergencies. How-

ever, rain — especially associated with wind — is a

harsh condition for ﬂying. Indeed, several drone mod-

els cannot ﬂy under rain. In that case, the team needs

to postpone missions and wait for better weather con-

ditions.

Flights are also limited by the range of communi-

cation and obstacles between the radio controller and

drone. The communication range, in turn, is affected

by a number of factors, including interference levels.

As of today, the Civil Defense Ofﬁce uses off-the-

shelf drones that are restricted to communication in

unlicensed bands — usually, the 900 MHz, 2.4 MHz,

and 5 GHz ISM bands. Because of their unlicensed

natures and the popularity of technologies such as

IEEE 802.11 and Bluetooth, those bands are currently

crowded in most urban areas. Thus, the communica-

tion between the drones and the ground station can be

severely affected, especially in densely populated re-

gions. Indeed, during our interviews, members of the

drone operation crew reported more than once situa-

tions where the control of the drone became unstable

likely due to communication issues.

Another problem reported by the crew is the co-

existence between drones and birds. Several missions

had to be interrupted because certain species of birds

— perhaps feeling threatened by the device — at-

tempted to attack the drone and disrupted the ﬂight.

According to the pilots, this is a particularly com-

mon occurrence when drones are far away from the

ground station. The lack of visual contact with the

device makes it harder for the pilots to anticipate the

approach of the birds — as they rely solely on the

relatively narrow ﬁeld of view of the drone’s camera.

Nevertheless, this type of event may cause the drone

to crash.

Another challenge is how to conciliate the needs

of the Civil Defense Ofﬁce with the Brazilian drone

legislation. For instance, one of Rio de Janeiro’s main

airports, Santos Dumont, is relatively close to certain

regions of Niter

oi. Because of the risks associated

with ﬂying drones nearby airports, whenever a mis-

sion requires a drone ﬂight in one of those regions, the

Brazilian legislation requires the Civil Defense Ofﬁce

to register the mission with the competent department

and wait for the proper permission — in fact, off-the-

shelf drones are programmed to recognize the vicin-

ity of airports and avoid entering those areas. While

requesting this type of permission can be feasible for

routine missions that are planned ahead of time, it can

impede the usage of drones for certain emergency ac-

tions.

Legislation can also be an obstacle for other types

of desirable drone applications. Take, for instance,

the idea of using drones to carry ﬁre balloons towards

safer areas. Overcoming the drag of a typical balloon

requires a drone of considerable size. Aside from all

the technical and ﬁnancial challenges involved in de-

signing and acquiring such an equipment, there are

regulatory issues as well — e.g., would there be ad-

ditional constraints regarding the areas or routes that

such a drone would be allowed to ﬂy? what additional

permits would be required from the pilots?

Regarding Civil Defense procedures and protocols

to generate their products using drones, the agents

reported a long time (e.g., weeks) to produce them.

They need to collect the data, then process it in of-

ﬁce and write the report outlining their conclusions.

The faster reports are generated, the faster actions are

taken on the incident. This can mean a signiﬁcant im-

provement to the ﬁnal result of the entire operation

demanded to the City Hall, and may even save lives.

Regardless of the model of the drone, properly

training the pilots is another important aspect. Re-

member that the Civil Defense Ofﬁce missions can

occur under very challenging circumstances — e.g.,

under rain, considerable wind. Moreover, the typical

missions conducted by the ofﬁce often involve push-

ing the drones to their limits in terms of both auton-

omy and range. Thus, pilots must be well aware of

such limits and must be prepared to ﬂy the drone un-

der non-ideal situations.

Finally, we note that a fundamental challenge is

choosing the right drone model. Drones can vary

widely in a number of ways — e.g., size, ﬂight au-

tonomy, load capacity, accessories. Depending on the

type of mission, certain aspects are more important

than others. For instance, search missions during a

disaster can last for days, thus requiring drones with

KMIS 2022 - 14th International Conference on Knowledge Management and Information Systems

Table 2: Summary of the main recommendations for each challenge or demands identiﬁed.

Challenges/Demands Recommendation Summary

Battery autonomy Multi-UAV, deﬁne points in ground for battery swap, hot-swap.

Weather conditions Investing in waterproof or splash-proof drones.

Network communication Study and use of LPWAN, 5G, FANET.

Choosing drones Survey of readily available drones on the market and sensors.

Regulation and Legislation Reduce bureaucratic processes, ﬂexibilize rules for emergency.

Training agents Use simulators of drone ﬂight.

Mapping risk areas Use of infrared/multispectral camera, humidity sensors, embedded in the drone.

Handling ﬁre balloon Study techniques and procedures to extinguish or redirect balloons.

Building surveillance Deﬁne protocols for the drone structural inspection, knowledge management.

Warning sound messages Deﬁne message and protocol in missions according to historical situations.

Supply delivery Specify drone capable to transport supply. Deﬁne protocols.

More agile processes Automate procedures to provide (quasi) real-time responses while in situ.

as much autonomy as possible. However, if the search

is carried out in a region of dense vegetation, acces-

sories, such as thermal cameras, might be of great

help. Unfortunately, that adds weight, which not only

demands a larger, high-capacity drone, but also re-

duces the autonomy. Indeed, given the wide range

of different missions carried out by the Civil Defense

Ofﬁce, it seems unlikely that a single drone model

will be able to cater to all requirements.

4.2 Improving or Recommending Drone

Usage

In the context of the PDPA, the Civil Defense Ofﬁce

is proposing a series of potential solutions for the de-

mands and challenges mentioned in Section 4.1. Ta-

ble 2 summarizes the main recommendations, in rela-

tion to challenges and demands, as described as fol-

low.

One of the recommendations is related to the bat-

tery autonomy issue. A multi-UAV system, also

called a drone swarm, is a strategy that help solv-

ing the problem of covering larger areas (Chen et al.,

2020). Instead of using only one drone for a mis-

sion, a group of drones is autonomously coordinated

in order to embrace more tasks and consequently ex-

plore more areas. Another approach to be explored

is the organization of strategic battery charging points

in the city or at the mission site, e.g. placing vehicles

in strategic positions for this purpose. Battery hot-

swap — changing the drone’s battery without restart-

ing their electronic components and, consequently,

the previously deﬁned mission — can also reduce the

down-time.

For the problem of ﬂying under bad weather con-

ditions, one can consider investing in waterproof or

splash-proof drones. This, however, is not trivial, as

such models are not commonly designed by manufac-

turers in order to lower costs and reduce the technical

complexity. An alternative for the Civil Defense Of-

ﬁce would be to develop a custom drone with this ca-

pability, which involves engineering skills.

In terms of enhancing communication, for urban

ﬂights that suffer from interference issues in crowded

areas, the Low Power Wide Area Networks (LP-

WAN) (Chaudhari et al., 2020) technologies should

be considered for ground communication with the

UAV. Those technologies — as IEEE 802.11ah and

LoraWAN — operate on long distances, low bit-rate

and low battery consumption, by exploiting the less

used sub-1GHz bands. However, they are specially

geared towards low-volume trafﬁc — LoraWAN, in

particular —, being perhaps suitable for telemetry and

command transmission. Furthermore, the emergent

5G networks can also help meet the communication

demands, but the antenna placement of such networks

is often optimized for covering the ground — where

most of the users of the mobile operators are. That

can be a challenge for their application for enabling

drone communications (Lin et al., 2019). One can

also consider the concept of Flying Ad Hoc Networks

(FANET), i.e., the usage of a multi-UAV system to ex-

tend the communication range by means of multi-hop

aerial communication between drones (Chen et al.,

2020).

On choosing the drone for a speciﬁc demand, a

survey of readily available drones on the market —

whose purchase is more feasible — is a fundamental

step. These drones are typically composed by a body

(e.g., rotors, propellers and assembly frame), a micro-

controller, a conventional camera and a sensing sys-

tem (e.g., accelerometers, altimeter, GPS and obstacle

sensors). Kits of parts to assemble custom drones are

also available. In this case, a study of sensors and ac-

tuators is relevant to identify which sensors are more

useful for the purposes of civil defense.

Drones for Civil Defense: A Case Study in the City of Niterói

Regarding regulation and legislation issues, based

on the report of the Civil Defense Ofﬁce, we notice

that is important streamline the bureaucratic processes

between the ofﬁce and the competent government

departments — especially, for the emergency mis-

sions. Since the Civil Defense Ofﬁce’s services are

government-owned, the rules for emergency ﬂights

in civilian prohibit areas, such as airports and mili-

tary zones, could perhaps be ﬂexibilized. Of course,

ﬂights themselves cannot become a risk for the pop-

ulation. Thus, this ﬂexibilization might require addi-

tional effort from the part of the ofﬁce, such as stricter

licenses for their pilots. A specialized system for a

quicker exchange of information between the ofﬁce

and the competent departments could also help, as

well as more direct processes.

Properly training agents of the Civil Defense Of-

ﬁce is also important. Drones can be used in several

situations and, according to the mission, they should

be included in the exercise drills. Several situations

associated with ﬂight conditions, such as battery life,

path choice, communication failures, could be mod-

eled by simulators and help in a mission planning.

Exposing the pilot to these situations before they actu-

ally occur can be decisive for the success of the actual

missions. The usage of simulators for such purposes,

however, requires good simulation models for all as-

pects involved in the mission, including the physics

of the ﬂight, but also communication issues, for ex-

ample.

In the context of mapping and surveillance of dis-

aster risk areas, considering the demands identiﬁed in

Subsection 3.3, we note that drones are able to mea-

sure the condition of soil and vegetation through im-

ages, if equipped with infrared and other multispec-

tral cameras. In a ﬁrst moment, satellite images can

detect potential risk areas in a large but distant region.

Then, a drone assembled with an infrared camera can

examine a speciﬁc area in more detail. Drones can

also measure the relative humidity of certain regions

and other environmental aspects, if equipped with the

proper sensor (such as an air humidity sensor). These

actions can prevent disasters such as landslides, wild-

ﬁres and irregular occupation of risk areas.

For handling ﬁre balloons, we see a need for

studying techniques that can be used to extinguish or

redirect balloons to areas without risk of ﬁre (such as

the sea or lake). This is not a trivial issue, as those bal-

loons are generally of large proportions — and, there-

fore, have too much drag to be pulled or carried by a

typical off-the-shelf drone. Even taking down the bal-

loon in a controllable fashion is a challenge, as cool-

ing down their heat source might require large vol-

umes of water or chemicals. As such, we anticipate

the need for a multidisciplinary effort for designing

and eventually equipping a proper drone with suitable

actuators for this task.

In terms of procedures and protocols while the

civil defense operations with drones, some proce-

dures can be automate to provide (quasi) real-time re-

sponses. We identiﬁed many information that can be

processed in situ rather than of being processed later

in the ofﬁce. Thus, conclusions can be drawn more

quickly, making it possible to expand data collection

to capture additional information. Taking the example

of the inspection of risk areas, agents can compute in-

formation on risk points, based on images, still in the

ﬁeld.

Deﬁning action protocols according to a speciﬁc

mission is also key to enable the use of drones for

several demands such as building surveillance, warn-

ing sound messages and supply delivery. Protocols

must deﬁne important stages of knowledge manage-

ment and decision-making, such as the processes of

measuring data, generating storing and disseminating

the information and knowledge, and making decisions

based on acquired knowledge. Effective information

and knowledge management techniques, especially

designed for the problems discussed, are therefore

crucial for optimizing processes in the secretariat.

Table 3 summarizes the current use of drones in

the Civil Defense Ofﬁce by roles (see Table 1) and

also the recommendations for future drone usage.

The difference between the current and future use of

drones by the ofﬁce is highlighted in the fourth col-

umn, labeled as “Future Drone’s Use”.

5 CONCLUSION

Drones are devices responsible for collecting infor-

mation from sensors carried by them. The relative

low cost and easy access to drones — especially, for

off-the-shelf models — has opened-up a large num-

ber potentially useful applications. But they use of-

ten complex procedures and are therefore candidates

to beneﬁt from information and knowledge manage-

ment systems. Smart cities, in particular, seem to be

a niche that can greatly proﬁt from the ﬂexibility of

drones. In this context, Niter

oi’s Civil Defense Ofﬁce

is a pioneer in the usage of drones for a plethora of

rescue and risk prevention activities in Brazil.

In this paper, we reported on the experience of

the ofﬁce in using those devices. We surveyed their

current use cases, detailing how drones have been or

could be helping the ofﬁce succeed at its missions.

We also reported issues found by the ofﬁce’s pilots

and technicians during their years using drones, as

KMIS 2022 - 14th International Conference on Knowledge Management and Information Systems

Table 3: Summary of current use of drones in the Civil Defense Ofﬁce by roles and recommendations for future drones’ use.

Role

Id.

Current

Drones’ Use

Summary of the Current Usage

Future

Drones’ Use

Recommendation

1 yes Drones only inspect risk areas us-

ing conventional cameras.

yes Drones can map and identify risk

areas using infrared cameras.

2 yes Drones only inspect risk areas us-

ing conventional cameras.

yes Drones can inspect a risk area us-

ing infrared cameras.

3 no - yes Deﬁne protocols to include drones

in building inspection.

4 no - yes Drones can be used to send sound

alert messages to the civilians.

5 no - yes Apply drones in exercise drills;

use simulators of drone ﬂights.

6 no - yes Drones can be used to transport

supplies for a risk area, if needed.

7 yes Drones capture conventional im-

ages of areas hit by disasters.

yes Drones can automate the current

process and improve evaluation.

Not applicable.

10 no - yes Drones as a tool to assist in the

training of human resources.

11 no - yes Data and procedures using drones

can feed the national system.

well as other usages that the ofﬁce envisions for those

devices. We also looked at the existing challenges

in meeting those future uses, and discussed possible

paths for realizing the drones’ full potential for the

Civil Defense Ofﬁce.

Towards that goal, our analysis has revealed obsta-

cles in both technical and legislative aspects of drone

usage. For example, autonomy and ﬂight range seem

to often hinder envisioned drone applications. As bat-

tery technology evolves, those issues should be miti-

gated to a certain extent. Ditto the issues with com-

munication range, that might become less pronounced

with the proliferation of 5G. Even so, regulatory ob-

stacles also need to be overcome both by the mod-

ernization of the relevant legislation, but mainly by

the cooperation between the regulatory bodies and the

Civil Defense Ofﬁce to ﬁnd safe yet streamlined pro-

cesses for the authorization of time-critical missions

and the usage of specialized drones.

ACKNOWLEDGEMENTS

This work is funded by the PDPA program of the City

Hall of Niter

oi.

REFERENCES

Alsamhi, S. H., Ma, O., Ansari, M. S., and Almalki, F. A.

(2019). Survey on collaborative smart drones and

internet of things for improving smartness of smart

cities. IEEE Access, 7:128125–128152.

Ayamga, M., Akaba, S., and Nyaaba, A. A. (2021). Multi-

faceted applicability of drones: A review. Technolog-

ical Forecasting and Social Change, 167:120677.

Chaudhari, B. S., Zennaro, M., and Borkar, S. (2020). LP-

WAN technologies: Emerging application characteris-

tics, requirements, and design considerations. Future

Internet, 12(3).

Chen, W., Liu, J., Guo, H., and Kato, N. (2020). Toward

robust and intelligent drone swarm: Challenges and

future directions. IEEE Network, 34(4):278–283.

de Moor, J. M., Stix, J., Avard, G., Muller, C., Cor-

rales, E., Diaz, J. A., Alan, A., Brenes, J., Pacheco,

J., Aiuppa, A., and Fischer, T. P. (2019). Insights

on hydrothermal-magmatic interactions and eruptive

processes at Po

as volcano (Costa Rica) from high-

frequency gas monitoring and drone measurements.

Geophysical Research Letters, 46(3):1293–1302.

Giordan, D., Hayakawa, Y., Nex, F., Remondino, F., and

Tarolli, P. (2018). Review article: the use of remotely

piloted aircraft systems (RPASs) for natural hazards

monitoring and management. Natural Hazards and

Earth System Sciences, 18(4):1079–1096.

Gohari, A., Ahmad, A. B., Rahim, R. B. A., Supa’at, A.

S. M., Abd Razak, S., and Gismalla, M. S. M. (2022).

Drones for Civil Defense: A Case Study in the City of Niterói

Involvement of surveillance drones in smart cities: A

systematic review. IEEE Access, 10:56611–56628.

Hassanalian, M. and Abdelkeﬁ, A. (2017). Classiﬁcations,

applications, and design challenges of drones: A re-

view. Progress in Aerospace Sciences, 91:99–131.

Jayaweera, H. M. and Hanoun, S. (2020). A dynamic artiﬁ-

cial potential ﬁeld (D-APF) UAV path planning tech-

nique for following ground moving targets. IEEE Ac-

cess, 8:192760–192776.

Jensen, O. B. (2016). Drone city – power, design and aerial

mobility in the age of “smart cities”. Geographica

Helvetica, 71(2):67–75.

Katila, C. J., Di Gianni, A., Buratti, C., and Verdone,

R. (2017). Routing protocols for video surveillance

drones in IEEE 802.11s wireless mesh networks. In

2017 European Conference on Networks and Commu-

nications (EuCNC), pages 1–5.

Kim, H., Mokdad, L., and Ben-Othman, J. (2018). Design-

ing UAV surveillance frameworks for smart city and

extensive ocean with differential perspectives. IEEE

Communications Magazine, 56(4):98–104.

Lin, X., Wiren, R., Euler, S., Sadam, A., M

att

anen, H.-L.,

Muruganathan, S., Gao, S., Wang, Y.-P. E., Kauppi,

J., Zou, Z., and Yajnanarayana, V. (2019). Mobile

network-connected drones: Field trials, simulations,

and design insights. IEEE Vehicular Technology Mag-

azine, 14(3):115–125.

Reis, L. C. D., Bernardini, F. C., Ferreira, S. B. L., and

Cappelli, C. (2021). An ICT governance analysis for

the digital and smart transformation of brazilian mu-

nicipalities. In DG.O2021: The 22nd Annual Interna-

tional Conference on Digital Government Research,

DG.O’21, page 327–338, New York, NY, USA. Asso-

ciation for Computing Machinery.

Shavarani, S. M., Nejad, M. G., Rismanchian, F., and Izbi-

rak, G. (2018). Application of hierarchical facility lo-

cation problem for optimization of a drone delivery

system: a case study of amazon prime air in the city of

san francisco. The International Journal of Advanced

Manufacturing Technology, 95(9):3141–3153.

Swinney, C. J. and Woods, J. C. (2021). The effect of real-

world interference on cnn feature extraction and ma-

chine learning classiﬁcation of unmanned aerial sys-

tems. Aerospace, 8(7):179.

KMIS 2022 - 14th International Conference on Knowledge Management and Information Systems