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<article article-type="research-article" xml:lang="en" dtd-version="1.1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-id />
      <journal-title-group>
        <journal-title xml:lang="hr">Zbornik Veleučilišta u Rijeci</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1848-1299</issn>
      <issn pub-type="epub">1849-1723</issn>
      <publisher>
        <publisher-name xml:lang="hr">Veleučilište u Rijeci</publisher-name>
        <publisher-name xml:lang="en">Polytechnic od Rijeka</publisher-name>
        <publisher-loc>Vukovarska 58
          <email xlink:href="	zbornik@veleri.hr">zbornik@veleri.hr</email>
          <ext-link xlink:href="http://www.veleri.hr/?q=zbornik">	http://www.veleri.hr/?q=zbornik</ext-link>
        </publisher-loc>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-categories>
        <subj-group subj-group-type="heading" xml:lang="hr">
          <subject>Pregledni rad
          </subject>
        </subj-group>
        <subj-group subj-group-type="heading" xml:lang="en">
          <subject>Review article</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title xml:lang="en">ANALYSIS OF AN INDOOR POSITIONING SYSTEMS </article-title>
        <trans-title-group>
          <trans-title xml:lang="hr">ANALIZA SUSTAVA ZA UNUTARNJE LOCIRANJE</trans-title>
        </trans-title-group>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Kaluža</surname>
            <given-names>Marin</given-names>
          </name>
          <email xlink:href="mkaluza@veleri.hr">mkaluza@veleri.hr</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Beg</surname>
            <given-names>Kristina </given-names>
          </name>
          <email xlink:href="mkaluza@veleri.hr">kbeg@veleri.hr</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">orcid.org/0000-0002-1579-4830</contrib-id>
          <name>
            <surname>Vukelić</surname>
            <given-names>Bernard </given-names>
          </name>
          <email xlink:href="mkaluza@veleri.hr">bvukelic@veleri.hr</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff1">
          <label>1</label>
          <institution xml:lang="en">Polytechnic of Rijeka</institution>
          <addr-line>Vukovarska 58, 51 000 Rijeka, Croatia</addr-line>
        </aff>
      </contrib-group>
      <pub-date>
        <month>05</month>
        <year>2017</year>
      </pub-date>
      <volume>5</volume>
      <issue>1</issue>
      <fpage>13</fpage>
      <lpage>32</lpage>
      <history>
        <date date-type="received">
          <day>15</day>
          <month>02</month>
          <year>2017</year>
        </date>
        <date date-type="accepted">
          <day>01</day>
          <month>04</month>
          <year>2017</year>
        </date>
      </history>
      <permissions>
        <license license-type="open-access">
          <license-p>CC BY-NC</license-p>
        </license>
        <license license-type="open-access" xml:lang="hr">
          <license-p>Puni tekst objavljenih radova smije se koristiti za osobnu ili edukacijsku svrhu uz poštivanje autorskih prava autora i izdavača. 
          </license-p>  
        </license>               
        <license license-type="open-access" xml:lang="en">
          <license-p>The usage of full-text of the articles can be used exclusively for personal, research-related or educational purposes, with regard to the authors' and publishers' rights. </license-p>
        </license>
      </permissions>
      <abstract xml:lang="hr">
        <p><italic>Recently, due to advances in the development of various technologies which can be
            used for locating, it is possible to develop systems which include software solutions
            for the user locationing and guidance in the interior, closed or covered areas where the
            existing location technologies and systems for locating and guidance applicable at open,
            outdoor areas cannot be used. </italic></p>
        <p><italic>This paper analyses the available hardware, software and network technologies
            which can be used for creating a positioning system for interior, closed or covered
            area. The paper analyses technologies which can be used in such distributed systems for
            the implementation of functionalities that are needed or required in the Indoor
            Positioning System (IPS). </italic></p>
        <p><italic>The paper describes the concept of the IPS system. It presents the IPS systems
            available on the market. It shows the technologies that can be used to implement the IPS
            system and the analyses of categories which affect the IPS system implementation. The
            paper demonstrates that none of the technologies analysed meet all of the observed
            categories while the BLE technology achieves the most favourable results in individual
            categories.</italic></p>
      </abstract>
      <trans-abstract xml:lang="en">
        <p><italic>Zbog napretka u razvoju raznih tehnologija koje se mogu koristiti za lociranje, u
            posljednje vrijeme razvijaju se sustavi koji uključuju programska rješenja za lociranje
            i navođenje korisnika u unutarnjem, zatvorenom ili natkrivenom prostoru, gdje se
            postojeće tehnologije za lociranje i sustavi za lociranje i navođenje koje se
            primjenjuju kod otvorenih, vanjskih prostora, ne mogu koristiti. </italic></p>
        <p><italic>U radu se analiziraju dostupne hardverske, softverske i mrežne tehnologije kojima
            je moguće izraditi sustav za unutarnje lociranje, odnosno tehnologije kojima takav
            distribuirani sustav po svom karakteru i implementiranim funkcijama postaje sustav za
            lociranje u zatvorenom prostoru (IPS, engl. </italic>Indoor Positioning System<italic>).
          </italic></p>
        <p><italic>Opisan je koncept IPS sustava. Prikazani su gotovi IPS sustavi dostupni na
            tržištu. Pokazane su tehnologije koje se mogu koristiti za implementaciju IPS-a i
            izrađena analiza kategorija koje utječu na implementaciju IPS-a. Pokazano je da niti
            jedna tehnologija ne zadovoljava sve promatrane kategorije, no BLE tehnologija omogućuje
            ostvarenje najpovoljnijih rezultata po pojedinim kategorijama.</italic></p>
      </trans-abstract>
      <kwd-group xml:lang="hr">
        <kwd>IPS</kwd> <kwd>indoor positioning</kwd>
      </kwd-group>
      <kwd-group xml:lang="hr">
        <kwd>IPS</kwd> <kwd>unutarnje lociranje</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec sec-type="intro">
      <label>1.	INTRODUCTION</label>
      <p>Indoor Positioning System (IPS<fn>
          <label>1</label>
          <p>IPS (Indoor Positioning System)</p>
        </fn>) is a system of network connected devices which is used for wireless locationing of
        objects and persons inside buildings and partly covered areas (<xref ref-type="bibr"
          rid="Lemmens">Lemmens, 2013</xref>.). Technologies used by those systems become
        commercially available in various forms (required hardware) and with various characteristics
        (functionality by means of visual contact, radio-frequency, magnetic field, sound). There is
        a large number of available technologies that can be used in the IPS system. Outdoor
        positioning systems usually use satellite technologies (eg. GPS<fn>
          <label>2</label>
          <p>GPS (Global Positioning System) is a system for determining a position on the
            ground.</p>
        </fn>) or network technologies (determining a location at the base station of the mobile
        service provider, Wi-Fi<fn>
          <label>3</label>
          <p>Wi-Fi is a standard for a wireless network</p>
        </fn> ). GPS technology has become widely available in the late 1990’s and has significantly
        improved the outdoor positioning system. Today, smart devices (smartphones, tablets,
        tracking devices, watches) often have a built-in GPS component.</p>
      <p>There is a need for locating in the interior area. Satellite positioning has not been
        functioning in closed areas, therefore it has led to the emergence of new technologies to
        make such a positioning possible. Indoor positioning is more complex than the outdoor
        positioning (by means of GPS) as the implementation of technologies used indoors may require
        some additional infrastructure. IPS could be designed to search for items or groups of items
        in the supermarket, to find the appropriate office within the building of an institution, to
        orient oneself within the hospital complex, to find certain stores within the mall, to get
        around easily at the airport, museum, etc.</p>
      <p>What technologies are available for developing IPS, what are their possibilities? For what
        IPS possibilities can available technologies be used? What functions does the indoor
        positioning system execute or control? </p>
      <p>The aim of the paper is to show which technology can be used as the basic technology for
        the IPS to achieve the best characteristics (functionalities) of the IPS. </p>
      <p>The paper describes some IPS functionalities, and examples of IPSs available on the market.
        Also describes technologies that can be used in IPS. The paper represents an analyses of
        some characteristics of IPS (and technologies that can be used in IPS): battery life,
        location accuracy, maintenance, system security, installation, maintenance costs, push
        notifications, blue dot navigation and signal sensitivity. The analyses can be used for the
        starting point of the selection of technologies for the IPS implementation.</p>   
    </sec>
    <sec>
      <label>2.	 IPS FUNCTIONALITIES AND EXAMPLES</label>
      <p>Technologies used for indoor positioning vary in accuracy, cost of implementation and
        installation and maintenance activities. </p>
      <p>IPS system is composed of three distinct elements (<xref ref-type="bibr" rid="Senion2016"
          >Senion, 2016</xref>): </p>
      <list list-type="bullet">
        <list-item>
          <p>a dynamic platform of the positioning system, </p>
        </list-item>
        <list-item>
          <p>location devices or signal transmitters,</p>
        </list-item>
        <list-item>
          <p>a mobile application that retrieves and interprets signals. </p>
        </list-item>
      </list>
      <p>Indoor positioning system constantly operates in order to determine the exact location of
        the device. The coordinates (latitude, longitude, and height / number of floors) are the
        output of such operation. In order for the coordinates to be applicable, they need context,
        that is, a map (<xref ref-type="bibr" rid="Senion2016">Senion, 2016</xref>).Basically, a
        technology that allows obtaining information on the location of objects within the building
        results in the following two concepts: knowing when the user is located near a certain
        point, or being able to determine the position of the user regardless of their location in
        the building. The first refers to a system based on proximity (PS<fn>
          <label>4</label>
          <p>PS (Proximity System)</p>
        </fn> ) and the other is the IPS system (<xref ref-type="bibr" rid="Senion2016">Senion,
          2016</xref>). </p>
      <p> PS uses location devices that operate with Bluetooth<fn>
          <label>5</label>
          <p>Bluetooth is a short-range wireless technology that enables wireless data communication
            between digital devices such as computer and digital camera – URL: <ext-link
              xlink:href="https://www.sony.ru/support/emanual/SRS-X55/HR/contents/TP0000629089.html"
              ext-link-type="uri"
              >https://www.sony.ru/support/emanual/SRS-X55/HR/contents/TP0000629089.html</ext-link></p>
        </fn> low energy (BLE<fn>
          <label>6</label>
          <p>BLE (Bluetooth Low Energy) is a Bluetooth technology that uses less energy</p>
        </fn> ) and it acts as transmitters that broadcast their identification data to nearby smart
        mobile devices. The PS is used for the purpose of finding the user's location (people and
        things) in certain moments. The location device provides information on the time when a
        person or thing is located within a range of a certain point, that is, of a location device.
        This information can be used to "target" customer located near a shop and for sending
        notifications. </p>
      <list list-type="bullet">
        <list-item>
          <p>The lack of such a system is the range of transmission. If the implementation of the PS
            is aimed at achieving greater connectivity with the user, it is necessary to set up
            location devices at various locations within the building. These location devices can
            also be a subset of an IPS (<xref ref-type="bibr" rid="Törnqvist">Törnqvist,
            2017</xref>).</p>
        </list-item>
        <list-item>
          <p>IPS includes a location device as part of a larger system that enables other
            functionalities for applications: route search, search for friends, enhanced marketing
            opportunities, detailed analytics.</p>
        </list-item>
        <list-item>
          <p>IPS uses multiple signals from location devices, as well as motion sensors and other
            sensors on the user’s smart mobile device. By combining these elements, the IPS can
            accurately calculate the position of the user. Some IPS systems include analytical
            processes of the system’s basic data and data created during system operation. Such
            processes can predict the future movement of the user even in buildings with multiple
            floors.</p>
        </list-item>
        <list-item>
          <p>When searching for a route, the IPS system functions in the same way as the GPS for
            outdoor positioning. Instead of retrieving the satellite signal, the IPS exchanges
            signals between the location devices and smart devices’ sensors. The functionality of a
            route search helps a user to manoeuvre in the area, such as a shopping centre or
            hospital. The guidance, as well as the prediction of the user’s movement, arebased on
            the current route. Locating friends works in the same way, allowing users to find each
            other indoors.</p>
        </list-item>
        <list-item>
          <p>IPS also helps to ensure marketing opportunities. For example, a shopping mall can
            define arbitrary areas where they want to display information or provide commercial
            advertisements. Areas can be installed and defined within the IPS system without the
            need for moving the hardware responsible for sending notifications to customers. </p>
        </list-item>
        <list-item>
          <p>IPS can also provide detailed analysis, even in real time, display user's movement in
            the building and enable a user to make decisions. From such analysis it is possible to
            see which zones in a shopping mall are more frequently visited.. IPS also enables the
            analysis of customer behaviour, for example, which shops are the most visited, which
            shop the customer has just passed by and what is his/her route, and even whether the
            customer has stopped in front of a shop window and in front of which shop window
            exactly.</p>
        </list-item>
        <list-item>
          <p>IPS is also applied at the health care institutions. The system can guide the patient
            to the office of a specific doctor. Another use of the IPS system in health care
            involves the use of location devices for medical equipment in order to locate certain
            equipment more easily, which is particularly useful in emergency cases.</p>
        </list-item>
      </list>
      <p>The main difference in the functions of the IPS in relation to the PS is in the fact that
        the IPS collects data on the movement of the user first and then it can analyse the traffic
        at certain parts of the system, while for the PS system it is necessary to already know in
        advance which parts of the system should be analysed in order to timely place the location
        devices on the desired position (<xref ref-type="bibr" rid="Törnqvist">Törnqvist,
          2017</xref>).</p>
      <p>The Wi-Fi technology was used at the very beginning of the indoor positioning. However,
        since it was not intended to be used for the purpose of positioning, the positioning was not
        precise enough and there was also a lot of collaboration between the phone and the network
        itself (<xref ref-type="bibr" rid="Meridian">Meridian, 2017</xref>). </p>
      <p>In Meridian company, at the time, one of their first projects was creating a mobile app for
        a large and famous museum. The museum was using one of the very first indoor location
        systems and it operated by measuring Wi-Fi signals to compute user location. These signals
        tended to fluctuate dramatically and the location quality was very poor as a result. In the
        museum’s app, the “blue dot” would float wildly around, jumping 30 feet at a time, and it
        felt very unreliable (<xref ref-type="bibr" rid="Meridian">Meridian, 2017</xref>). </p>
      <p>“Blue dot” represents the user’s movement in the area and it also enhances the user
        experience. When the user moves through the room the “blue dot” should move smoothly and
        also be as accurate as possible regarding the user real position. It is equivalent of the
        real-time location recognition as GPS is in the outdoors. </p>
      <p>The "blue dot" was not only showing the movement of the user incorrectly, but it also
        appeared randomly on the screen. To improve the accuracy of the positioning, the algorithm
        that would allow this improvement was enhanced. At the same time, the user experience, that
        is "the blue dot experience" was also worked on, in order to accurately display the user's
        movements. The user’s movement from one room to another was also enhanced, without taking
        into account small intermediate steps meaning Meridian redesigned the entire app experience
        around the assumption that the user location just was not going to be precise. They focused
        the “getting directions” experience around going from one big hall full of exhibits to
        another instead of all small steps that the user takes to get there. The hall exits are
        perfectly well-marked in the space and the user just needs to know which one is next (<xref
          ref-type="bibr" rid="Meridian">Meridian, 2017</xref>). </p>
      <p>In most cases, the Wi-Fi component is already supported or even included on users’ smart
        devices, and the buildings can be adequately equipped with the appropriate infrastructure.
        Sometimes, counters need to be installed at the entrance area, as well as a video camera at
        specific locations in order to analyse the user's movement by recording the user’s
        locations.</p>
      <p>A mobile application guides the user to certain services and products and also displays
        notifications and targeted marketing ads.</p>
      <p>An administrative interface, the so-called dashboard, may be positioned at the central
        site, and thus manages the system (updating locations, managing alerts, etc.).</p>
      <p>Backend software contains the following components (<xref ref-type="bibr" rid="Mattsson"
          >Mattsson, 2014</xref>):</p>
      <list list-type="bullet">
        <list-item>
          <p>system for running location-based alerts,</p>
        </list-item>
        <list-item>
          <p>analytical system based on movement of the user,</p>
        </list-item>
        <list-item>
          <p>database containing location information,</p>
        </list-item>
        <list-item>
          <p>management and security layers to protect data (Administrative Tools),</p>
        </list-item>
        <list-item>
          <p>integration into existing systems, for example, e-commerce, marketing automation, POS <fn>
              <label>7</label>
              <p>POS means a Point of Sale – URL:
                http://www.posmatic.com/point-of-sale/what-is-point-of-sale.php</p>
            </fn>, content management,</p>
        </list-item>
        <list-item>
          <p>API <fn>
              <label>8</label>
              <p>API means Application Programming Interface – URL:
                http://laris.fesb.hr/java/paketi.htm</p>
            </fn> to import and export data and location-based triggers. </p>
        </list-item>
      </list>
      <p>Certain examples of the IPS system are presented below.</p>
      <p><bold>2.1 Senion</bold></p>
      <p>"SenionAB" is a company in Sweden that has developed an IPS called StepInside. Apart from
        user instructions on how to locate a specific place in form of tabs, this system also offers
        some additional options: reports on the movement of people who use the system, information
        about how many users have visited a particular area at a particular time. It also offers
        notifications to customers on the basis of virtual zones in the area where they are located.
        It is also possible to determine the points of interests of users and provide them with
        dynamic navigation experience (<xref ref-type="bibr" rid="Senion2017">Senion,
        2017</xref>).</p>
      <p>The system uses https / AES 128-bit encryption to ensure the integrity and protect against
        unwanted users’ "intrusion" on the background software components, encrypted identifiers of
        location devices and continuous performance and user activities monitoring (<xref
          ref-type="bibr" rid="Senion2017-2">Senion, 2017-2</xref>).</p>
      <p>The technology used by this IPS has not been explicitly mentioned. Some sources indicate
        the use of public Wi-Fi system (<xref ref-type="bibr" rid="Senion">Senion, 2015,
          </xref><xref ref-type="bibr" rid="Senion2015-2">2015-2</xref>), some point to the use of
        location devices that use BLE technology (beacons - sensors that transmit a BLE signal
          (<xref ref-type="bibr" rid="Senion2015-3">Senion, 2015-3</xref>). Senion website mentions
        that the company uses a technology using advanced sensors which provide the exact location
        of the device with the help of fusion algorithm and smartphone motion and radio sensors
          (<xref ref-type="bibr" rid="Senion2015-4">Senion-4, 2015</xref>). The use of those
        technologies for achieving additional functions of the system, e.g. analysis of the area and
        movement of users, management of BLE transmitters, user interaction with points of interest,
        user interaction with the specified zones in the building have also been mentioned (<xref
          rid="Senion2015-4" ref-type="bibr">Senion-4, 2015</xref>). Beacon Management System is
        used for locating all the location devices and for their maintenance (<xref ref-type="bibr"
          rid="Senion2016">Senion-4, 2016</xref>).</p>
      <p><bold>2.2 Infsoft</bold></p>
      <p>German company "INFSOFT GmbH" offers indoor navigation, indoor analytics, monitoring and
        location services since 2006 (<xref rid="Infsoft" ref-type="bibr">Infsoft, 2016</xref>).
        This IPS uses location nodes, location identifiers, UWB<fn>
          <label>9</label>
          <p>UWB (Ultra-wideband) is a short-range radio technology.</p>
        </fn> (<xref ref-type="bibr" rid="Infsoft">Infsoft, 2016</xref>), Wi-Fi and beacon devices
        for indoor positioning. Apart from the development of all-in-one solution for large
        customers, scalable and SDK<fn>
          <label>10</label>
          <p>SDK (Software Development Kit) is a set of development tools required to build, test,
            and debug Android applications - URL: <ext-link ext-link-type="uri"
              xlink:href="http://www.informatika.buzdo.com/pojmovi/mobile-4.htm"
              >http://www.informatika.buzdo.com/pojmovi/mobile-4.htm</ext-link></p>
        </fn> packages are also in offer. </p>
      <p>It allows client-based and server-based positioning. With the client-based positioning (the
        client usually being a smart device), a navigation service is used and the use of the
        application is also required. The technologies used are Wi-Fi networks that provide user
        location with 5-15 meters accuracy or BLE transmitters whose radio transmitter emits signals
        used by the application to calculate the position with 1-3 meters accuracy. Regarding the
        server-based positioning, a method that does not require the application is used, however,
        this type of positioning cannot achieve communication with the user. The method is used to
        locate objects and people, or when generating analysis on the movement of the user. This IPS
        uses its own developed location nodes that detect all smart devices that are able to receive
        Wi-Fi signals and BLE transmitters; location codes that are similar to nodes, more flexible
        and more suitable for monitoring several buildings in a large area; and various technologies
        for indoor positioning of other manufacturers such as Cisco, Aruba and Xirrus. (<xref
          ref-type="bibr" rid="Infsoft">Infsoft, 2016</xref>).</p>
      <p><bold>2.3 	IndoorAtlas</bold></p>
      <p> Finnish company "IndoorAtlas Ltd." has built the IPS using geomagnetic technology. IPS
        includes a platform in the Cloud<fn>
          <label>11</label>
          <p>Cloud is the concept of the division of the programming environment that uses the Web
            as a platform, and allows applications and documents sent from anywhere in the world to
            be stored and kept at predetermined servers - URL <ext-link
              xlink:href="http://security.lss.hr/arhiva-dokumenata/ cloud-computing.html"
              ext-link-type="uri">http://security.lss.hr/arhiva-dokumenata/
              cloud-computing.html</ext-link></p>
        </fn> using geomagnetic technology in order to determine the position of a person located
        indoor (<xref ref-type="bibr" rid="Sterling">Sterling, 2014</xref>). In the process,
        magnetic fields are used to map the building, Wi-Fi infrastructure is required inside the
        building and an integrated compass on the smart device. It is stated on the company’s Web
        portal that the data was very stable over time as opposed to RF<fn>
          <label>12</label>
          <p>RF (Radio Frequency) is a measure of the rate of oscillation of electromagnetic waves -
            URL <ext-link
              xlink:href="http://searchnetworking.techtarget.com/definition/radio-frequency"
              ext-link-type="uri"
              >http://searchnetworking.techtarget.com/definition/radio-frequency</ext-link></p>
        </fn> signals with a Wi-Fi hot spot's or Bluetooth transmitters (<xref ref-type="bibr"
          rid="Happich">Happich, 2016</xref>). The geomagnetic technology used has 1-2 meters
        accuracy (<xref ref-type="bibr" rid="Happich">Happich, 2016</xref>). Other indoor
        positioning technologies use hardware components that need implementation and maintenance,
        while geomagnetic technologies do not require that. The room should be mapped out first in a
        manner that a person who collects the data heads from a known point of departure and
        confirms the data collected at other points of space. The user that implements the IPS can
        create 2D maps even before the data is collected. (<xref ref-type="bibr" rid="Happich"
          >Happich, 2016</xref>).</p>
      <p>It is used in airports in which the route and time required for the user to reach a certain
        output is determined, and provides research of facilities at the airport. Moreover, it is
        also used at various points of sale and has an advertising role (<xref ref-type="bibr"
          rid="IndoorAtlas">IndoorAtlas, 2017</xref>). </p>
      <p>The system has been implemented at the Shinjuku, Shibuya and Tokyo metro stations. (<xref
          ref-type="bibr" rid="GISuser">GISuser, 2016</xref>). </p>
      <p>The application of the IPS on the gaming platforms was also announced, so there is a
        possibility of playing "Pokemon Go" indoors in near future (<xref ref-type="bibr"
          rid="Cardoza">Cardoza, 2016</xref>).</p>
      <p><bold>2.4 Philips Lighting </bold></p>
      <p>The Philips company produces household appliances, medical equipment, audio equipment and
        lighting. It consists of three divisions: "Philips Consumer Lifestyle", "Philips Healthcare"
        and "Philips Lighting" (<xref ref-type="bibr" rid="Philips">Philips, 2017</xref>).</p>
      <p>In Philips, it is considered that the lighting has already been installed in all indoor
        spaces and it is more natural to create a system for internal positioning out of a lighting
        system, than to install a completely separate infrastructure. Philips IPS system uses
        Philips VLC technology. With the help of VLC, each installation sends its unique ID to the
        user’ smart device and the system can accurately determine the user's location in the store.
        VLC is installed directly in the Philips LED luminaires and does not require additional
        installation, maintenance or power. The luminaires provide all the benefits of the LED
        lighting, including high energy savings in relation to the classical lighting systems, and
        they also provide the infrastructure for service delivery for indoor positioning. In
        addition to LED lighting, the indoor positioning system comprises both iOS and Android SDK
        packages and cloud services.</p>
      <p>The system does not require, collect nor store user data. Application users are logged in
        to the system anonymously. (<xref ref-type="bibr" rid="Philips2017-2">Philips,
        2017-2</xref>).</p>
      <p>The store in which Philips has installed its lighting is able to provide its customers with
        new services (help in getting around the store and finding a promotion) and reduce
        electricity consumption by 50% (<xref ref-type="bibr" rid="Afzal">Afzal, 2015</xref>).</p>
      <p>VLC lights in the store serve as a system for indoor locating. Each light bulb sends an
        identification code that is detected by the camera on a smart device and identifies the
        user's location. A mobile application submits this information to the user.</p>
    </sec>
    <sec>
      <label>3.	TECHNOLOGIES FOR IPS</label>
      <p>The previous chapter has demonstrated the systems for indoor positioning. Each of them uses
        some types and combinations of technology. The technologies used in IPS systems will be now
        presented.</p>
      <p><bold>3.1 BLE </bold></p>
      <p>Bluetooth technology is a wireless communication standard that is used to exchange data at
        a close distance. It was developed in 1994 by Ericsson, and in 1998 Ericsson, IBM, Intel,
        Nokia and Toshiba set up a special competent authority, the "Bluetooth Special Interest
        Group" (SIG). The role of the competent authority is to improve standards, proper
        implementation and licensing of Bluetooth technology.</p>
      <p>The main features of Bluetooth technology are low-cost Bluetooth devices, low power
        consumption, small range, robustness and global use. Bluetooth provides transfer speed of 1
        Mbit/s and uses unlicensed frequency band of 2.4 to 2.485 GHz, that is, it uses ISM
          <underline>area (</underline>industrial, scientific and medical) where frequency is
        globally harmonized. Also, the Bluetooth offers a radio connection with other systems.
        Devices from different manufacturers are mutually incompatible, and packet and channel
        switching is allowed (<xref ref-type="bibr" rid="Hamidović">Hamidović, 2009</xref>).</p>
      <p>In mid-2010, the Bluetooth SIG announced the Bluetooth 4.0 specification, which included:
          <italic>Classic Bluetooth, Bluetooth high speed</italic> and <italic>Bluetooth low
          energy</italic> protocols.</p>
      <p>Bluetooth low energy (BLE) is characterized by a very small size, low cost, low power
        consumption with the possibility of several years of work on a small power source (AAA
        batteries) and compatibility with mobile devices, tablets and computers.</p>
      <p>To install the BLE technology in devices, Bluetooth 4.0 introduces two modes of operation:
        single-mode and dual-mode. Single-mode operation includes only the integration of the BLE
        functionality into the controller, while dual-mode operation allows the integration of BLE
        and Bluetooth functionality in the standard controller. Device manufacturers have these two
        options at their disposal and it is important to point out that devices with single-mode
        operation cannot communicate with devices that use classic Bluetooth protocol (<xref
          ref-type="bibr" rid="Akiba">Akiba et al., 2014</xref>).</p>
      <p>Today, most mobile devices are produced with a support for standard Bluetooth and for the
        BLE, that is, a Bluetooth microcontroller with dual-mode operation is installed in devices.
        Mobile operating systems that currently support the BLE are: Android 4.3 and higher; iOS 5
        and higher; Windows Phone 8.1; Blackberry 10 (<xref ref-type="bibr" rid="Paganini">Paganini,
          2015</xref>). </p>
      <p>The BLE broadcasts signals from transmitters that operate on batteries. The technology is
        available on most devices (smartphones, tablets). It uses the so-called beacon-e
        (transmitter) and location devices that are cheap, small in size, have a long battery life
        and do not require an external power source. The device detects the signal from the
        transmitter and can roughly calculate the distance to it and thus estimate the location of
        the device (<xref ref-type="bibr" rid="Blaz">Blaz, 2015</xref>).</p>
      <p> Using the BLE technology, the transmitters notify the nearby devices on their presence.
        Nearby devices (mobile devices, tablets) can be subscribed to notifications of the
        transmitters and can receive a variety of content (such as text, images and URL). At the
        same time, the transmitters can be used for contactless payments in a similar way as NFC<fn>
          <label>13</label>
          <p>NFC (Near Field Communication) is a wireless technology that works on short distances –
            URL: <ext-link xlink:href="http://mob.hr/sto-je-i-kako-radi-nfc/" ext-link-type="uri"
              >http://mob.hr/sto-je-i-kako-radi-nfc/</ext-link>
          </p>
        </fn></p>
      <p>The lifespan of the transmitter is estimated at 5-8 years, transmitters are resistant to
        dust and water according to IP67 standard (<xref ref-type="bibr" rid="Senion2017"> Senion,
          2017 </xref>) and have a precision of 1-3 meters. (<xref ref-type="bibr" rid="Infsoft">
          Infsoft, 2016. </xref>)</p>
      <p>In order for the BLE technology to be used, it is necessary to turn on the Bluetooth or
        BLE. </p>
      <p>The BLE transmitters have the ability to send notification to the user when the user is at
        a particular location (<xref ref-type="bibr" rid="Mattsson"> Mattsson, 2014 </xref>).</p>
      <p><bold>3.2 WPS (Wi-Fi positioning system)</bold></p>
      <p>Wi-Fi is a technology that uses radio waves to connect to the network. Wi-Fi connection is
        established with the help of a wireless adapter which creates a wireless local area network
        in the vicinity of a wireless router, which is connected to the network and allows users to
        access Internet services. Once configured, Wi-Fi allows you to wirelessly connect to devices
        by emitting frequencies between 2.4GHz and 5GHz depending on the amount of data passing
        through the network (<xref ref-type="bibr" rid="AAkai">Aakai, 2016</xref>).</p>
      <p>The term WPS originated from the Skyhook Wireless company which used the term to outline
        its Wi-Fi positioning system. Google, Apple, various phone manufacturers and phone operators
        have drawn up very extensive databases of Wi-Fi access points by connecting Wi-Fi access
        point with GPS locations of a smart device (<xref ref-type="bibr" rid="Zahradnik">Zahradnik,
          2016</xref>). Anonymous determination of the user location is an integral part of any
        contract with a mobile operator. Most smart phones allow the user to turn off location
        services. A possibility to exempt a network form saving into the WPS base is supported by
        Google. It is necessary to add an extension "_nomap" to the name of the Wi-Fi network and
        the network will not be mapped. WPS can be combined with a triangulation of repeaters of
        mobile operator and GPS in order to obtain reliable and accurate data on the position of
        users under a wide range of conditions, including passages between tall buildings and
        enclosed areas where GPS signals may be weak or intermittent. Disadvantages of WPS
        technology are the following: WPS does not work if the user is located outside the range of
        Wi-Fi signals, it is necessary to continuously update the database of Wi-Fi access points
          (<xref ref-type="bibr" rid="Zahradnik">Zahradnik, 2016</xref>).</p>
      <p>Wi-Fi can be used in a similar way as the BLE transmitters, however, it requires an
        external power source, higher installation costs and more expensive equipment. Smart device
        need not be connected to a Wi-Fi network, but Wi-Fi connection needs to be enabled. The
        signal is stronger and can cover a longer distance than the BLE technology and the precision
        is 5-15 meters (<xref ref-type="bibr" rid="Blaz">Blaz, 2015</xref>).</p>
      <p>There are several positioning techniques that use Wi-Fi technology. Triangulation is one of
        them. Triangulation uses the intersection of three circles of Wi-Fi access points in order
        to enable the exact position of the user. The triangulation collects signal strength of all
        existing Wi-Fi access points. The user’s distance form a certain access points is calculated
        according to the signal strength, and thus, the exact position is obtained. The procedure is
        simple and easy to implement. Triangulation is also called dynamic positioning method (<xref
          ref-type="bibr" rid="Palaskar">Palaskar et al., 2014</xref>).</p>
      <p> Another positioning technique using a wireless access network is based on measuring the
        intensity of the received RSSI<fn>
          <label>14</label>
          <p>RSSI means Received Signal Strength Indication – URL: <ext-link ext-link-type="uri"
              xlink:href="http://www.academia.edu/9895197/WLAN_Wi_Fi"
              >http://www.academia.edu/9895197/WLAN_Wi_Fi</ext-link></p>
        </fn> signal and "fingerprinting” method. The MAC address of a device is also used. The
        application on the smart device of a user calculates the current position of the user based
        on the intensity of the received signal and the "fingerprinting” method (<xref
          ref-type="bibr" rid="Gaudlitz2015">Gaudlitz, 2015</xref>). </p>
      <p>The "fingerprinting" method consists of two phases: online and offline. In the offline
        training phase, the base of RSS<fn>
          <label>15</label>
          <p>RSS means Received Signal Strength. </p>
        </fn>data with the corresponding coordinates of the location is prepared. Data on the signal
        strength is collected from several different locations, and then stored in the database.
        This is the most important phase and the accuracy of locating depends on it. In the online
        phase, the user sends a query concerning the RSS data to the database, that is, known
        coordinates are compared with the unknown ones and the most accurate location is obtained
        Various examples of algorithms are used to find matching entries in the database with
        dynamic RSS. The most challenging task of the method is to design the RSS database of prints
        and its maintenance. Any addition, exclusion, or removal of furniture requires a re-update
        of the database. The problem can be easily solved if another sensor is installed in the
        system - a camera (<xref ref-type="bibr" rid="Palaskar">Palaskar et al., 2014</xref>). </p>
      <p><bold>3.3 Geomagnetic technology</bold></p>
      <p>The magnetic field detection can also be used for indoor positioning by using a compass
        sensor. The so-called "fingerprinting” method is used for mapping magnetic fields at a
        particular place after which a smart device can use the same map in order to find indoor
        locations. This technique can be applied only in certain circumstances, where the magnetic
        fields indoors are stable (<xref ref-type="bibr" rid="Blaz">Blaz, 2015</xref>). IndoorAtlas
        is currently the only company that implements this technology. It is stated that the
        distortion of magnetic fields in buildings due to material they are made of was ideal for
        magnetic imprint (<xref ref-type="bibr" rid="Sterling">Sterling, 2014</xref>). The more
        metal there is in the area, the imprint is more unique. It also said that the geomagnetic
        technology can be implemented in any indoor areas. Such a system does not require the
        installation of additional hardware. It is sufficient to pass through a room to collect data
        for magnetic positioning. The plan of the building is set on the cloud system and is
        connected with the magnetic imprints of the area. It takes about an hour to cover the 25,000
        m2 of space (approximately 2,322 m2) in the accuracy of 1-2 meters. Non-technical staff
        members, any user, have also been enabled to generate magnetic imprint by using only their
        smart phone and instructions (<xref ref-type="bibr" rid="Sterling">Sterling,
        2014</xref>).</p>
      <p><bold>3.4 VLC</bold></p>
      <p>Visual Light Communication (VLC) is a wireless technology that uses LED light as a
        communication channel. Just like Wi-Fi technology, the term Li-Fi technology derived
        thereof. It can be used as a standalone solution or as an addition to radio communication
        (Wi-Fi, mobile). The VLC operates in a way that the LED switches from ON to OFF state and
        vice versa at a high frequency (nano seconds) (<xref ref-type="bibr" rid="Dilouie">Dilouie,
          2014</xref>).</p>
      <p>The LED sends a pattern of a blinking light received by a receiver, that is, a camera on a
        smart phone. The pattern is converted into an encrypted form and sent to the server. On the
        server, the encrypted form of the pattern is compared to the one on the map. When the
        identical encrypted form of the pattern is found on the map, the system implies that the
        user is positioned beneath the LED.</p>
      <p>The downside of VLC technology is that the camera on the user’s device has to have visual
        contact with the LED. The device will not receive notification if visual contact is not
        achieved, as opposed to the BLE technology transmitter that does not require the same. VLC
        determines the location very accurately, even up to 5 cm.</p>
      <p><bold>3.5 Other technologies</bold></p>
      <p> Near Field Communication is a wireless technology that works on short distances and does
        not require a power source. A smart device will detect the NFC device and read the serial
        number if the device is located at a distance of 30 cm. This technology is currently used in
        the system of sale, however, it can also be used for precise positioning indoors. The NFC
        technology is available on newer smart devices. The NFC could replace QR<fn>
          <label>16</label>
          <p>QR (Quick Response) is a two-dimensional graphic code – URL: <ext-link
              xlink:href="http://www.netokracija.com/qr-kod-8766" ext-link-type="uri"
              >http://www.netokracija.com/qr-kod-8766</ext-link></p>
        </fn> codes, as QR codes must be visible, they require a stronger lighting and a camera
          (<xref ref-type="bibr" rid="Blaz">Blaz, 2015</xref>). </p>
      <p>The signal is reachable at the distance of up to 10 meters. The NFC can be used to increase
        the robustness of the IPS system that uses Bluetooth technology, since it is able to quickly
        connect to a smart device. </p>
      <p>Radio Frequency Identification (RFID) is an automatic identification method by means of
        contactless communication techniques. NFC i RFID are relatively similar. Unlike the NFC,
        RFID technology cannot simultaneously send and receive data. Apple products still do not
        fully support this service (<xref ref-type="bibr" rid="Infsoft2017">Infsoft,
        2017</xref>).</p>
      <p>The gyroscope is a device used for calculating the position, measuring and maintaining
        orientation. Most smart devices have built-in gyroscope and compass. A smart device can use
        this information as an addition to other technologies for more precise positioning (<xref
          ref-type="bibr" rid="Blaz">Blaz, 2015</xref>).</p>
    </sec>
    <sec>
      <label>4.	ANALYSIS OF TECHNOLOGICAL CHARACTERISTICS OF IPS</label>
      <p>A more detailed explanation of certain categories of analysis is given below: location
        precision, battery life, maintenance, safety, installation costs, mapping method, the type
        of customer, push notifications and the "blue dot" navigation. The previously mentioned
        analysis categories represent the starting point for the selection of technologies for the
        IPS system implementation.</p>
      <p><bold>4.1 Location precision</bold></p>
      <p>The precision (accuracy) of locationing shows at what distances the indoor positioning is
        possible. The importance of the category depends on where the positioning system will be
        used. For example, if the user should be guided to a certain exit at the airport or to the
        doctor's office, the precision of 2 or 5 meters should not be a problem. If a person should
        be guided to a specific product or a group of products, greater precision will be
        needed.</p>
      <p><bold>4.2 Battery life</bold></p>
      <p>With regard to the analysed technologies, only BLE transmitters use battery and its lifespan
        depends on the model of the transmitter, battery type and settings, and it may last for more
        than two years.</p>
      <p>The data on the cost of LED bulbs with VLC technology and the lifespan of a light bulb were
        not found in the source. The lifespan will depend on the wattage of a light bulb and
        estimated operating hours. If the light bulb has an estimated range of 50,000 operating
        hours, and if it is turned on 24 hours a day, the lifespan of a light bulb can be 5.7
        years.</p>
      <p><bold>4.3 Maintenance</bold></p>
      <p>Maintenance may be analysed for BLE, Wi-Fi and VLC technologies since they are hardware
        components. Hardware components are not used in geomagnetic technology, so the maintenance
        may be more difficult to examine. </p>
      <p>BLE technology requires skilled installers and constant calibration, depending on the
        changes in the observed area. Maintenance is made easier if management of the transmitters
        is centralized.</p>
      <p>Given that the Wi-Fi infrastructure often already exists, maintenance of Wi-Fi technology
        for indoor positioning is facilitated. Current maintenance also includes the adjustment to
        changes in the environment and to infrastructure changes. This may be a malfunction of
        hardware or software, system upgrade or turning on or off of the access point if the router
        is controlled by a third party, e.g., the store owner at the mall (<xref ref-type="bibr"
          rid="Luo">Luo et al, 2013</xref>).</p>
      <p>The costs and maintenance of the VLC LED light bulbs are not significant. When the lifespan
        of the light bulb expires, it is replaced by a new one.</p>
      <p>The hardware components may break down or be stolen, therefore, the replacement will be
        necessary. Wi-Fi and BLE transmitters are more exposed than the light bulbs. </p>
      <p><bold>4.4 Safety</bold></p>
      <p>The data on the user’s location is a sensitive information that can present a problem if
        available or insufficiently protected. The level of system security can be explained by
        technical characteristics.</p>
      <p> Client-based indoor positioning with BLE transmitters or via Wi-Fi system is generally
        safe. In such a system, the position is determined directly on the user’ smart device
        without further communication with the server. The data are not forwarded further. BLE
        transmitters are not storage media for keeping users' personal information. They only
        contain certain key information such as the device ID<fn>
          <label>17</label>
          <p>ID (Identifier) is a unique number used for identification </p>
        </fn> in order to gain access to and control the device. </p>
      <p>When it comes to applications for anonymous tracking, smart device’s UID<fn>
          <label>18</label>
          <p>UID (Unique Identifier) is a unique number used for identification– URL: <ext-link
              ext-link-type="uri"
              xlink:href="http://internetofthingsagenda.techtarget.com/definition/unique-identifier-UID"
              >http://internetofthingsagenda.techtarget.com/definition/unique-identifier-UID</ext-link></p>
        </fn>, BLE transmitter’s UID, RSSI and timestamp<fn>
          <label>19</label>
          <p>Timestamp is the time of an event recorded by a computer – URL: <ext-link
              ext-link-type="uri" xlink:href="http://whatis.techtarget.com/definition/timestamp"
            /></p>
        </fn> are used and stored on the server. The smart device’s MAC<fn>
          <label>20</label>
          <p>MAC (Media Access Control) is a unique identifier that is found in almost all network
            devices – URL: <ext-link ext-link-type="uri"
              xlink:href="http://www.sveznadar.info/20-WINTipsTricks/11-MrezaRazniPojmovi/12-1-Pojmovnik-MAC.html"
              >http://www.sveznadar.info/20-WINTipsTricks/11-MrezaRazniPojmovi/12-1-Pojmovnik-MAC.html</ext-link></p>
        </fn> address is also retrieved. User information will not be transmitted if the user is
        registered anonymously. </p>
      <p>The BLE transmitters are protected by a "rolling ID" method in order to prevent a third
        party from attempting to use them. Only the operator of the transmitter has the appropriate
        "key" to decode the transmitter. The transmitter’s ID is changing, therefore it is necessary
        to use the system administration interface for a user (administrator) to be able to access
        the transmitter (Winkler, 2016).</p>
      <p>The source states that the LED light bulbs with VLC technology are extremely safe, but
        there is no example and / or a detailed description mentioned. Philips respects the privacy
        of users in a way that the system is designed so that the user data are not required,
        collected nor stored. Application users are logged in to the system anonymously.</p>
      <p><bold>4.5 Installation costs</bold></p>
      <p>When it comes to magnetic technology, the installation of the device is not needed, so there
        are no installation costs.</p>
      <p>Regarding the VLC technology, costs can be high if all current luminaires are replaced. In
        terms of initial installation, the costs are not that high since there is also a need for
        the installation of luminaires. The price of a LED light bulb using VLC technology should be
        compared to a price of a normal light bulb in order to estimate the installation costs. </p>
      <p>For Wi-Fi, installation costs are not high if one intends to use the existing
        infrastructure, or at least a part of it. If, however, access points are introduced only for
        those purposes, costs of devices and installations are observed as the cost of
        installation.</p>
      <p>Depending on the model, strength and settings, the price of BLE transmitter ranges from
        5-30 dollars for a piece (<xref ref-type="bibr" rid="Martin">Martin, 2016</xref>). The unit
        price of the device is not high, but when it comes to IPS modelling, transmitter location
        will be defined, so, considering the quantity, the total cost of installation can be
        high.</p>
      <p><bold>4.6 Mapping method</bold></p>
      <p> Mapping a certain area in order to implement IPS. For Wi-Fi and VLC technology, it is
        necessary to map the area where the system will be installed and, if necessary, the system
        will be re-calibrated. In terms of BLE technology, similar procedures are carried out and
        applications for managing all devices are used. When it comes to magnetic technology, users
        can independently collect data on magnetic fields which are then submitted to the
        manufacturer of the IPS. The data is then processed and made available for use. A user can
        introduce any change in the same way. The cost of such a technique of mapping area is not
        significant since it does not require field work of professional staff in order to map the
        area. Waze<fn>
          <label>21</label>
          <p>Waze is one of the larger community-based traffic and navigation application in which
            users share real-time traffic and road information – URL: <ext-link ext-link-type="uri"
              xlink:href="https://waze.com.hr/o-waze-aplikaciji/detaljnije-o-aplikaciji"
              >https://waze.com.hr/o-waze-aplikaciji/detaljnije-o-aplikaciji</ext-link>/</p>
        </fn> uses similar technique (<xref ref-type="bibr" rid="Sterling">Starling, 2014</xref>). </p>
      <p><bold>4.7 Client types</bold></p>
      <p>The client types are Android and iOS users. All technologies, apart from Wi-Fi-based IPS
        systems, can be used by both types of clients, while the above mentioned system can be used
        only by Android users. Devices with iOS 4.3 (since March 2011) and above no longer support
        positioning via Wi-Fi technology on the client (<xref ref-type="bibr" rid="Gaudlitz"
          >Gaudlitz, 2016</xref>). In its announcement of iOS 8, Apple introduced its indoor
        positioning location service integrated into the operating system. Using the motion sensor,
        Wi-Fi and iBeacon technology devices can detect when the user is located in the room and
        start determining the location. The technology will also be used in public places where
        Apple would be able to introduce the service in cooperation with building owners. The
        service will not be available to Android users (<xref ref-type="bibr" rid="McGlynn">McGlynn,
          2014</xref>).</p>
      <p><bold>4.8 Push notifications</bold></p>
      <p> Push notifications<fn>
          <label>22</label>
          <p>Push notification is a delivery of information from software applications to computing
            device without a specific request from the recipient (client) – URL: <ext-link
              ext-link-type="uri" xlink:href="http://www.mojatvrtka.hr/sto-su-push-notifikacije/"
              >http://www.mojatvrtka.hr/sto-su-push-notifikacije/</ext-link></p>
        </fn> are only enabled using BLE technology. </p>
      <p><bold>4.9 Blue dot navigation</bold></p>
      <p>During indoor navigation, the user's position is continuously monitored and a blue dot is
        visible on the screen of the smartphone. The blue dot shifts depending on the movement of
        the user. This term became known as the blue dot experience when the dot on the screen moves
        in accordance with the user.</p>
      <p>BLE technology can support real-time monitoring with the help of certain algorithms and
        densely distributed BLE transmitter. The blue dot experience is not possible if there is not
        a sufficient number of BLE transmitters in the building. When using BLE technology, the blue
        dot experience is usually achieved in combination with another technology. There is such a
        solution (although limited). Estimote Indoor Location system can provide visualization of a
        user approximate position within space in a real-time (<xref ref-type="bibr" rid="Estimote"
          >Estimote, 2017</xref>). Estimote beacons need to be set up on the center of each of the
        walls. By walking near the beacons user is mapping the area and configuring the beacons.
        Once complete, the user location is automatically saved in Estimote Cloud, and the user can
        use their SDK to see real-time user positions within that space. (<xref ref-type="bibr"
          rid="Estimote">Estimote, 2017</xref>).</p>
      <p><bold>4.10 Signal change sensitivity</bold></p>
      <p>BLE technology, when used for IPS is sensitive on the changing radio conditions. Just the
        presence of humans in the room can change drastically the signal perception in different
        positions in the room. For this reason to obtain good localization and signal perception
        when installing the beacons the line of sight is sought when possible between the receiver
        and the beacon, typically placing the beacons above head height. (<xref ref-type="bibr"
          rid="Steczkiewicz">Steczkiewicz, 2015</xref>).</p>
      <p>Various surfaces can cause interference with Bluetooth signals, including glass and metal.
        Additional beacons can be used to counter any interference in the room. (<xref
          ref-type="bibr" rid="Estimote">Estimote, 2017</xref>).</p>
      <p>Wi-fi signal can also be blocked by household electronics, bluetooth devices, physical
        barriers or humans (<xref ref-type="bibr" rid="Bertolucci">Bertolucci, 2011</xref>).</p>
      <p>Indoor magnetic field contains location information but this information is interfered in
        by hard/soft-iron effect, hand quiver, and electronic noise. These interferences decrease
        the distinguishability of location fingerprints in magnetic field based localization systems
          (<xref ref-type="bibr" rid="WenhuaShao">Wenhua Shao et al., 2016.</xref>)</p>
      <p>VLC technology is sensitive in a sense that everything that interferes with visual line of
        sight of LED light is directly interfering in functioning of the indoor positioning
        technology.</p>
    </sec>
    <sec>
      <label>5.	DISCUSSION OF THE ANALYSIS RESULTS</label>
      <p><xref ref-type="table" rid="t1">Table 1 </xref>shows aggregated data of the analysis of the
        technologies for IPS. </p>
      <p><table-wrap id="t1">
        <label>Table 1</label>
        <caption><p>Technologies and their features</p></caption>
          <table>
            <tbody>
              <tr>
                <td  align="left" valign="bottom"> </td>
                <td  align="center" valign="bottom"><bold>BLE</bold></td>
                <td  align="center" valign="bottom"><bold>Wi-Fi</bold></td>
                <td  align="center" valign="bottom"
                  ><bold>Magnetic</bold></td>
                <td  align="center" valign="bottom"><bold>VLC</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Location
                    precision</bold></td>
                <td  align="left" valign="bottom">2 m</td>
                <td  align="left" valign="bottom">5 m</td>
                <td  align="left" valign="bottom">2 m</td>
                <td  align="left" valign="bottom"><bold>5 cm</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Battery</bold><bold>
                    life</bold></td>
                <td  align="left" valign="bottom">5-8 years</td>
                <td  align="left" valign="bottom"><bold>No</bold></td>
                <td  align="left" valign="bottom"><bold>No</bold></td>
                <td  align="left" valign="bottom">5,7 years/0-24h</td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"
                  ><bold>Maintenance</bold></td>
                <td  align="left" valign="bottom">average</td>
                <td  align="left" valign="bottom">average</td>
                <td  align="left" valign="bottom"><bold>Easy</bold></td>
                <td  align="left" valign="bottom"><bold>Easy</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Safety</bold></td>
                <td  align="left" valign="bottom"><bold>high**</bold></td>
                <td  align="left" valign="bottom">average</td>
                <td  align="left" valign="bottom"><bold>High</bold></td>
                <td  align="left" valign="bottom"><bold>High</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Installation
                    costs</bold></td>
                <td  align="left" valign="bottom">Average</td>
                <td  align="left" valign="bottom">High</td>
                <td  align="left" valign="bottom"><bold>Low</bold></td>
                <td  align="left" valign="bottom">Average</td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Mapping
                  method</bold></td>
                <td  align="left" valign="bottom">Device management</td>
                <td  align="left" valign="bottom">Mapping/fingerprinting</td>
                <td  align="left" valign="bottom"
                  ><bold>Environment</bold></td>
                <td  align="left" valign="bottom">Mapping</td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Programming
                    environment</bold></td>
                <td  align="left" valign="bottom"
                  ><bold>Android/iOS</bold></td>
                <td  align="left" valign="bottom">Android*</td>
                <td  align="left" valign="bottom"
                  ><bold>Android/iOS</bold></td>
                <td  align="left" valign="bottom"
                  ><bold>Android/iOS</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Push
                    notifications</bold></td>
                <td  align="left" valign="bottom"><bold>Supported</bold></td>
                <td  align="left" valign="bottom">Not supported</td>
                <td  align="left" valign="bottom">Not supported</td>
                <td  align="left" valign="bottom">Not supported</td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Blue dot
                    navigation</bold></td>
                <td  align="left" valign="bottom"><bold>Supported</bold></td>
                <td  align="left" valign="bottom"><bold>Supported</bold></td>
                <td  align="left" valign="bottom"><bold>Supported</bold></td>
                <td  align="left" valign="bottom"><bold>Supported</bold></td>
              </tr>
              <tr>
                <td  align="left" valign="bottom"><bold>Signal change
                    sensitivity</bold></td>
                <td  valign="bottom"><bold>Sensitive</bold></td>
                <td  valign="bottom"><bold>Sensitive</bold></td>
                <td  valign="bottom"><bold>Sensitive</bold></td>
                <td  valign="bottom"><bold>Sensitive</bold></td>
              </tr>
              <tr>
                <td rowspan="1" colspan="2" align="left" valign="bottom">*iOS does not support Wi-Fi
                  scanning</td>
                <td  align="left" valign="bottom"> </td>
                <td  align="left" valign="bottom"> </td>
                <td  align="left" valign="bottom"> </td>
              </tr>
              <tr>
                <td rowspan="1" colspan="5" align="left" valign="bottom">**Technology features with
                  an advantage in relation to another under a certain entry are marked in bold</td>
              </tr>
            </tbody>
          </table>
        <table-wrap-foot><p>Source: authors</p></table-wrap-foot>
        </table-wrap></p>
      <p>The precision of locating is highest when it comes to VLC technology with accuracy of 5 cm. </p>
      <p>Regarding the battery life, the highest efficiency was observed in the best technologies
        that actually did not use batteries, and those were Wi-Fi and geomagnetic technologies. </p>
      <p>Geomagnetic technology is the easiest one to maintain since it does not require any
        hardware, so updating the map is very easy and it can be performed by a user with the help
        of instructions. VLC technology is integrated into the LED lighting which needs to be
        regularly maintained, depending on the longevity of the light bulb. </p>
      <p>Security is very high when it comes to BLE, magnetic and VLC technology, as explained in
        details above. </p>
      <p>The installation costs are the lowest for geomagnetic technology since it does not require
        any installation of hardware. </p>
      <p>The best mapping is observed with geomagnetic technology since it can be done by an
        ordinary user and professional knowledge is not required. </p>
      <p>As far as the platform is concerned, all technologies support iOS and Android operating
        systems, except for Wi-Fi technology which is not supported in iOS 4.3 and higher. Apple
        eliminates this possibility and develops its own system of indoor positioning that will be
        enabled only to iOS users. </p>
      <p>Push notifications are supported only by BLE technologies and this is also why BLE
        technologies are used in combination with some other technologies. Combining technologies
        could give some functionalities of the IPS that would not be possible if technologies were
        being used separately. </p>
      <p>Blue dot navigation is supported on all researched technologies.</p>
      <p>The signal change sensitivity was also researched and all of the technologies had the same
        problem. They all had some possibilities of interferences, e.g. some objects, humans,
        another technology with the same radio signal. </p>
      <p>Companies that want to implement indoor positioning should clearly define their needs. It
        is not possible to say that one technology is the best for using in the IPS. If during an
        implementation in the IPS individual technologies are combined, better IPS features can be
        achieved due to their individual characteristics. Thus, for example, VLC or geomagnetic
        technology may be combined with BLE technology. Wi-Fi is not a good choice of technology for
        IPS since it is not supported in iOS, and it is not basically designed for indoor
        locationing. </p>
      <p>Aspects of every explained category is important. Companies should know their needs and
        depending on them they have to choose the best suited technology. For example, hospitals or
        airports do not need a very high accuracy like supermarkets so they can achieve indoor
        positioning system by simply implementing BLE technology. On the other hand, supermarkets do
        need high precision but also need push notifications to share their marketing ideas so they
        should use a combination of technologies like VLC and BLE. In the long run, companies should
        consider thefrequency of changing batteries, or a possibility of stealing a technology.
        Also, the should cosider the following: how easy it is to maintain the system, could current
        personnel maintain it or should the company have additional cost of maintaining the system
        by associates (developer). Also, how safe is the system for the company and its users.</p>
      <p>Considering all these characteristics, the BLE technology as an indoor positioning
        technology individually achieves the most favourable results.</p>
    </sec>
    <sec>
      <label>6.	CONCLUSION</label>
      <p>Certain technologies used in the indoor positioning system have been presented in the
        paper. The very concept of the indoor positioning is quite new and it is difficult to say
        that one technology presents a standard. This domain is still being researched and such
        systems are reaching their market.</p>
      <p>We have described IPS, its characteristics and its basic technologies. We have analysed
        technological characteristics of IPS on a few IPS examples. </p>
      <p>Results of the analyses shows that none of the analysed technologies achieve the best
        results according to all analysed characteristics, but BLE technology is the most favourable
        one. BLE technology individually achieves the most favourable results. Also, the Wi-Fi
        technology achieves the most unfavourable results. </p>
      <p>In the implementation of an IPS, a company should choose a certain technology on the basis
        of the preferred functions of the system, the type of building where the technology will be
        implemented in and its available budget.</p>
      <p>IPS technology standard still does not exist. Eventually, one of the existing technologies,
        a combination of these technologies, or even a new technology can become a standard.</p>
    </sec>
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</article>
