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Approfondissement Scientifique Indoor Positioning System to serve in Healthcare

Student: Jean-Baptiste Roche Batch : 117

Period :September 2016

Département : IT Chef de projet ICAM : Ahmed Rhiat

Client : ICAM – projet de recherche Européen INCASE ChefIntroduction de projet............................................................................................................................................. client : Ahmed Rhiat 3

Approfondissement scientifique Indoor Positioning System to serve in Healthcare

1. Positioning Techniques........................................................................................................................ 4 1.1 Fingerprinting ................................................................................................................................ 4 1.3 AoA method or Triangulation ........................................................................................................ 5 1.4 TOA-Based Algorithms or Trilateration ......................................................................................... 6 1.5 TDOA.............................................................................................................................................. 7 1.5 Inertial navigation system ............................................................................................................. 7 1.6 Map requirement .......................................................................................................................... 8 2.Technologies used for IPS (Indoor Positioning system) ....................................................................... 9 2.1 WI-FI .............................................................................................................................................. 9 2.2 RFID ............................................................................................................................................... 9 2.2.1 Passive RFID .......................................................................................................................... 10 2.2.2 Active RFID............................................................................................................................ 11 2.3 Beacons ....................................................................................................................................... 12 2.4 Bluetooth ..................................................................................................................................... 13 2.5 Ultrasound technology ................................................................................................................ 14 2.6 UWB............................................................................................................................................. 14 2.7 VLC ............................................................................................................................................... 15 2.8 Geomagnetic ............................................................................................................................... 17 Resume .............................................................................................................................................. 17 3. Application for Healthcare ................................................................................................................ 18 3.1 Traceability .................................................................................................................................. 18 3.2 Monitoring................................................................................................................................... 18 3.3 Reactivity ..................................................................................................................................... 19 3.4 Communication ........................................................................................................................... 20 3.5 Data mining ................................................................................................................................. 21 Conclusion ............................................................................................................................................. 22 Bibliography........................................................................................................................................... 23 Page 2 sur 25 Jean-Baptiste Roche

Année : 2016-2017, Période : A


Introduction Our project has been made in the context of a worldwide interest in iOT1 research and especially on the need to find a system, in addition to GPS which localize outdoor, in order to localize indoor. Numerous companies and universities conduct research on it. The project also derives from a bigger European research project, called InCase, which works on the Industry 4.0. ICAM is taking part of this project and launched a work consisting in the development of a smart warehouse demonstrator. Three main teams had already worked on it. The first one worked on a smart shelf, where it is possible, by a website, to monitor the stock in real time, and get input/output data history. RFID2 tags are stuck on the product, and detected by RFID reader. The second one worked on an intelligent trolley that moves on its own. It communicates with the shelf, which sent it the actual stock and supply orders. The trolley automatically responds to the order and moves to the shelf. The third team had begun to work on positioning system, but mostly for drone command control. This year, the work is done in cooperation with two students, from Polytech Lille, which focus on the future production operator. Nowadays, being able to locate something inside is interesting for many applications. To create smarter industries, an objective is to be able to track products, tools, machines, people in the plant, to know exactly where they are, to gain in security, to improve flux management, to get data on real time, to be able to monitor the process, to improve security, to access to richer information and proceed to data analytics. With the GPS3 system, based on satellites, it is perfectly possible to be localized but only outdoor. Buildings interfere in the GPS signal, and make the positioning system impossible. That how indoor positioning system became a main challenge in industry 4.0 research. Even if several technologies are available to do that, there is still some improvement to make, especially in term of precision. In this report, the aim is to present this technology and focus on applications for healthcare. Indeed the technology can’t work for itself, it is a support, a way to meet people need but it is not an end in itself. The technology alone is useless, that is why the report goes deep through the needs and the principal interests and utility of indoor positioning system. It also concern other technologies relative 1

internet of things : connect object

2

Radio Frequency Identification : see p.10

3

Global Positioning System : working with satelites

Page 3 sur 25 Jean-Baptiste Roche



to it, or that can be coupled with it, mainly RFID technology. As far as healthcare is concerned, the research is very global and will involve medical organization, treatment and management at home, or at the hospital. The first part will focus on the different algorithms that are used in positioning determination. This part is useful to understand the choice of the technologies and the different challenges that are faced. The second part will treat indoor positioning system different technologies, a state of the art of what it is currently possible to do, how it is set up and what are the different advantages and disadvantages of these different systems. The last part will give a good view of the need and the possible systems that can be made in the context of healthcare, in particular in term of traceability, monitoring, reactivity and communication.

1. Positioning Techniques 1.1 Fingerprinting This technology is based on a significant work of preparation of a basic model that will have the main play in the system. The model of the space, call « fingerprint » is made with a calculation of signal power at each point of the space forming a meshing. The data are stored associated with the coordinates of where they were measured. After that, the system is ready to function. When a device try to be located, it calculated again its signal power and compare it to those stored in the phone. It takes the coordinates which are associated with the signal power the closest as the one calculated. It is mainly used with Wifi, Bluetooth, and geomagnetism. But this technology requires a hard preparation of the model and had to be updated when the space organisation is modified.[1]




1.3 AoA method or Triangulation AOA, « Angle of Arrival » technique, is the estimation of the signal reception angles, from at least two sources, that are compared with either the signal amplitude or carrier phase across multiple antennas. The method is more precise with more sources. However, the main technologies are disable to use correctly angular measures. This algorithm is more used for outdoor application, like radar or in navigation with electromagnetic wave. We call that radiogoniometry. [1] Page 5 sur 25 Jean-Baptiste Roche



1.4 TOA-Based Algorithms or Trilateration TOA, « Time Of Arrival »is the most famous method. It is used when the distance between a transmitter and a receiver can be estimated, generally with the power signal or with one-way propagation time between them. This distance is interprated as a circle with the radius equals to the distance. With three transmitters, we can trace three circle and calculate the intersection point. The time synchronization of all transmitters is required whereas the receiver synchronization is unnecessary; any possibility of significant delay must be accounted for during calculation of the correct distance. [2]




1.5 TDOA The principle of TDOA, “Time Diference of Arrival”, is to use the difference in time at which the signal emitted by a target arrives at multiple measuring units. Three fixed receivers give two TDOAs and thus provide an intersection point that is the estimated location of the target. This method requires a precise time reference between the measuring units. Like TOA, TDOA has other drawbacks. In indoor environments, a Line Of Sight (LOS) channel is rarely available. Moreover, radio propagation often suffers from multipath effects thus affecting the time of flight of the signals. [2]

1.5 Inertial navigation system This method has the advantage not to require any signal but only the starting position location. It can be used particularly in case of loss of signal, or if the subject to locate is moving. Indeed, it is far faster and more acurate to use INS than to update the calculation of positioning algorithms. Researchers at the University of Michigan are working on a timing & inertial measurement unit (TIMU). The single chip TIMU prototype contains a six axis IMU (three gyroscopes and three accelerometers) and integrates a highly-accurate master clock into a single miniature system, smaller than the size of a penny. This chip integrates breakthrough devices (clocks, gyroscopes and accelerometers), materials. [1]




Three pieces of information are needed to navigate between known points ‘A’ and ‘B’ with precision: orientation, acceleration and time. This new chip integrates state-of-the-art devices that can measure all three simultaneously. [1]

1.6 Map requirement Locating a person or device indoors is only half of the solution. For the location to be meaningful for navigation or other purposes, service providers need accurate indoor maps. There’s a new industry creating those data. We can assist to a mapping race where diferent companies are mapping buildings around the World; Micello recently announced it had mapped 15,000 indoor venues. Nokia and Google are also working on improving there mapping system in a cooperative way. They propose to the users to add an indoor map as an image, and place it on the right place to integrate their outdoor map [3]. As far as healthcare is concerned, various companies propose, as a service to map hospitals. [1]




2.Technologies used for IPS (Indoor Positioning system) 2.1 WI-FI Wifi is a wireless technology set up to work on intern network. The component needed are tags, wifi connector or access point and a controller. However it can use the wifi network already in place. It radiowave frequencies can varies from 2.4 GHz to 5GHz and it range is around 100m [4]. In indoor positioning system, we use the intensity of the wifi signal, called the RSSI (Received Signal Strength Indication). [6] Advantages

Disadvantages

Possibility to use the network

High electric consumption

Accuracy

Tags size

Standard protocol

Equipement price and set up price Hacking risks

Therefore the wifi is not always perfectly working. It can be deformed by environment disruptions, or it can sometimes face some coverage hole in the wireless network. To enhanced the meshing of the network, others tools can be added. For example, if a smartphone is used, other captors contained in the smartphone can be used : the compass, gyroscope and the velocity meter. [7] The localisation method using wifi are the patterning, the fingerprinting or Chronos, a new technology made by MIT searcher and will be explained later. Wifi is often used in combination with other technologies more accurate and less electric consumer.

2.2 RFID RFID is a technology allowing to pick up distant informations using radio frequency identification (RFID) tags.it provides a low cost, effective way to connect IT systems with the assets, materials, staff and locations of businesses. The tags have read and write capabilities. Data stored on RFID tags can be changed, updated and locked. Newer innovations in the RFID industry include active, semi-active and passive RFID tags Page 9 sur 25 Jean-Baptiste Roche



At a basic level, tag works in the same way: -Data stored within an RFID tag's microchip waits to be read. -The tag's antenna receives electromagnetic energy from an RFID reader's antenna. -Using power from its internal battery or power harvested from the reader's electromagnetic field, the tag sends radio waves back to the reader. -The reader picks up the tag's radio waves and interprets the frequencies as meaningful data.[8]

2.2.1 Passive RFID Passive RFID systems use tags with no internal power source and instead are powered by the electromagnetic energy transmitted from an RFID reader. Passive RFID tags are used for applications such as access control, file tracking, race timing, supply chain management, smart labels, and more. The lower price point per tag makes employing passive RFID systems economical for many industries. The drawback is that the range is short (less than 35m), the com Some disturbance can be caused by metal object, or fluids.

Advantages

Disadvantages




Tag size, flexibility, life time, price

Short Range

Accuracy

Sensible to environment disturbance (fluids, metal)

Compatibility

Equipement price

Passive tag are used at different frequencies according to it utilisation. 125 – 134 KHz – Low Frequency (LF) : An extremely long wavelength with usually a short read range of about 1 – 10 centimeters . This frequency is typically used with animal tracking because it is not affected much by water or metal. 13.56 MHz – High Frequency (HF) & Near-Field Communication (NFC) : A medium wavelength with a typical read range of about 1 centimeter up to 1 meter. This frequency is used with data transmissions, access control applications, DVD kiosks, and passport security – applications that do not require a long read range. NFC technology possess an encoder and an encryption embedded that allow it to be used it in smartphone for payments 865 – 960 MHz – Ultra High Frequency (UHF) :– A short, high-energy wavelength of about a one meter which translates to long read range. Passive UHF tags can be read from an average distance of about 5 – 6 meters, but larger UHF tags can achieve up to 30+ meters of read range in ideal conditions. This frequency is typically used with race timing, IT asset tracking, file tracking, and laundry management as all these applications typically need more than a meter of read range.

As the LF and NFC are working only on short distance range, IPS don’t use this technology. On the opposite, UHF is commonly used for IPS with the bluetooth technology.[5]

2.2.2 Active RFID Active RFID systems use battery-powered RFID tags that continuously broadcast their own signal. Active RFID tags are commonly used as “beacons” to accurately track the real-time location of assets or in high-speed environments such as tolling. Active tags provide a much longer read range than passive tags, but they are also much more expensive. There are two main frequencies used by active systems : 433 MHz and 915 MHz. It is chosen according to user preference, tag selection, or environmental considerations but companies Page 11 sur 25 Jean-Baptiste Roche



generally prefer RFID systems that work with the 433 MHz because it has a longer wavelength and react better to disruption like metal or fluids. The particularity of the active RFID is that appart from classic components (reader, interogator and antenna), it contains its own power source, an internal battery. This power allow the system to have very long read ranges and a large memory bank. Typically, active RFID tags are powered by a battery that will last between 3 – 5 years, but when the battery fails, the active tag will need to be replaced. There is two kinds of active RFID tags: transponders and beacons. Active transponders tag wait to receive a signal from the reader to answer a signal back with the data needed. It doesn’t use it battery when it is out of range of the reader. They are commonly used in secure access control and in toll booth payment systems. Beacons, at the opposite, doesn’t wait for a request from the reader but continuously send its specific informations (every 3-5 sec). They are very very common in indoor lpositionning system.Active tag’s beacons can be read hundreds of meters away, but, in order to conserve battery life, they may be set to a lower transmit power in order to reach around 100 meters read range.[8]

Advantages

Disadvantages

Extremely long range

Equipement and set up price

Accuracy

Sensible to environmental disturbance (fluids, metal)

2.3 Beacons Beacons, are widely use in retail shops especially for geofencing.It is used with a Bluetooth protocol, it is easy to set up, and it represents a good component for indoor positioning. Lot of companies propose solutions with beacon, for example Apple, which launch the iBeacon. [9] Pros and cons of IPS* using beacons : Page 12 sur 25 Jean-Baptiste Roche



Advantages

Disadvantages

cost-effective, unremarkable hardware

additional hardware

low energy consumption

app is required for client based solutions

flexible integration into the existing infrastructure (battery-powered or power supply via lamps and the domestic electrical system) works where other positioning techniques do not have a signal compatible with iOS and Android high accuracy compared to WiFi (up to 1m)

2.4 Bluetooth Bluetooth technology is a short range wireless connectivity standard, exchanging data using UHF radiowave. This technology is constantly improving from it creation in 1994. Different versions appeared with some new specificities. As the bandwidth is short, the data exchanged cannot be too heavy so the technology is less use to transfer data but more for IoT (Internet of things). The Bluetooth standard, like WiFi, uses the FHSS technique (Frequency-Hopping Spread Spectrum), which involves splitting the frequency band of 2.402-2.480 GHz into 79 channels (called hops) each 1MHz wide, then transmitting the signal using a sequence of channels known to both the sending and receiving stations. Thus, by switching channels as often as 1600 times a second, the Bluetooth standard can avoid interference with other radio signals. The Bluetooth standard is based upon a master/slave operational mode. The term "piconet" is used to refer to the network formed by one device and all devices found within its range. A master can be simultaneously connected to as many as 7 active slave devices. Page 13 sur 25 Jean-Baptiste Roche



In reality, at a given moment, the master device can only be connected to a single slave at once. Therefore, it quickly switches between slaves in order to make it seem as if it is simultaneously connected to all the slave devices. [9] Bluetooth Highspeed (Bluetooth Version 3.0), which offered faster communication and lower power consumption Bluetooth Smart or Bluetooth Low Energy [7] (technically referred to as Bluetooth Version 4.0+). As these names suggest, this version is better at connecting a wider range of simpler devices, uses much less power, and is much easier to integrate into mobile (iOS and Android) applications. [10] Wifi and Bluetooth are often used together because they have complementary characteristics. Bluetooth is mainly used for linking computers and electronic devices for a specific mission over very short distances, often for only brief or occasional communication using relatively small amounts of data. It's relatively secure, uses little power, connects automatically, and in theory presents little or no health risk. Wi-Fi is designed to shuttle much larger amounts of data between computers and the Internet, often over much greater distances. It can involve more elaborate security and it generally uses much higher power, so arguably presents a slightly greater health risk if used for long periods. As wifi technology, Bluetooth use the RSSI method for positioning. [6]

2.5 Ultrasound technology Ultrasound can also be used in IPS. The system is based on a simple principle : a device broadcasting ultrasound, for example a loudspeaker or a self-contained panel and a receptor, a mike. all smartphones contain a mike, so are compatible and can be used for this technology; The range is approximately 15 to 20m. The signal is inaudible and there is no RF so there is no problem of nuisance. The principle advantage is that it can work in an offline atmosphere because it doesn’t need any activation to interact. [1] As the range is short, this technology is not common, or used combined with other technology. Ultrasound will be used for specific area needing accurate micro-location. Ultrasound technique of localisation : TDOA or multilateration

2.6 UWB UWB (Ultra Wide Band) is defined as an RF signal occupying a portion of the frequency spectrum that is greater than 20% of the center carrier frequency, or has a bandwidth greater than 500 MHz. This allows UWB transmitters to transmit large amounts of data while consuming little transmit energy. Page 14 sur 25 Jean-Baptiste Roche



UWB can legally operate in the range 3.1 GHz up to 10.6 GHz, at a limited transmit power of 41dBm/MHz. [15] UWB can be used for positioning by utilizing the time difference of arrival (TDOA) of the RF* signals to obtain the distance between the reference point and the target/ UWB has many advantages, such as the penetrating power, low power consumption, resistance to multi-path effects, high security, low complexity, and highly accurate positioning and so on. Therefore, UWB technology can be applied to indoor stationary or moving objects and people location tracking and navigation, and can provide very accurate positioning accuracy. For the moment, this technology is the most accurate with a cm precision. [15]

2.7 VLC Visible light communications (VLC) is a wireless communication technology in which the visible spectrum ( between 400 and 800 THz (780–375 nm) [10] is modulated to transmit data. It uses the propagation of the light. The transmission is made by emission of binary data in the form of light pulses. This technology provide a double utility : communication and illumination. [21]




Li-Fi, an abbreviation for Light Fidelity, is a form of Visible Light Communication (VLC) technology which delivers high-speed, bidirectional, networked mobile communications by using light from lightemitting diodes (LEDs). It transmits binary data in the form of light streams and thus is a subset of Optical Wireless Communication (OWC) which refers to all types of optical communications where cables (optical fibres) are not used. The range of Li-Fi vary depending on the strength of the light which is being emitted by the LED.

Lifi has also some weakness. Indeed, it require to keep the light on every time so it can be environmentally and practically problematic especially in domestic uses. Therefore, at the opposite of others technologies, if a smartphone is used,it has to be kept in the range of LED light, otherwise it is not able to communicate. However it can be turn in something good for privacy, because the customer can choose to avoid receiving data by putting his phone in Page 16 sur 25 Jean-Baptiste Roche



his pocket. Finally, Lifi is ineficient in spaces where the sunlight is, so it can’t be used close to a shop window. [21]

2.8 Geomagnetic Modern buildings all have a unique magnetic signature. Fingerprinting is used for this technology. The building's structure and materials interact with the Earth’s magnetic field and that yields a unique magnetic map for each floor, which once recorded and stored in the cloud, can be used to accurately pinpoint and track a person’s location indoors. Today's magnetometers are sensitive enough to make this work. [13]

Therefore the data is very stable over time unlike RF signals from WiFi hotspots or Bluetooth beacons, and this technology is easy to set up, simply because it is a software-only solution, with no hardware infrastructure to deploy and maintain. It is also easy to scale across millions of users.

Resume Wireless positioning system

Positioning Algorithms

Positioning Precisions

RFID

RSSI

Cm

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