T863203 3CR T863203 3CR
LOCATION TECHNOLOGIES
INTRODUCTION
Senior Lecturer Jari-Pekka Rontu, M.Sc (Eng.), M.Sc (Sport Sciences) Oulu University of Applied Sciences
Course Status
2
This Course is a part of DEGREE PROGRAMME IN INFORMATION TECHNOLOGY (Master of
INFORMATION TECHNOLOGY (Master of Engineering), which contains 60 crs
This course will be held in english; all materials and
lectures will be given in english
Course Description
3
Learning objectives: The student will know the main principles of location applications in different
principles of location applications in different wireless communication systems. He or she can estimate the suitability of different technologies for various applications.
Contents: The student will learn how radio signal is used in location applications and understand
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different network, satellite and short range location methods. The emphasis is on the short range location applications.
Course Description (cont.)
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Requirements: A course work (presentation, prestudy, practical measurement exercises) and active attending practical measurement exercises) and active attending to the lessons and exercises, also in the discussions after each student presentations
Literature: Teacher’s materials and student presentations.
Supplementary material:
Alan Bensky: Wireless Positioning Technologies and applications
Alan Bensky: Wireless Positioning, Technologies and applications, Artech House, 2008
Prerequisites: No prerequisites needed.
Assessment: Grading scale 0 - 5.
Practical Arrangements of the Course
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The course will be held on Monday afternoons, at 16.15 p.m., 4-5 hours per day
There will be no exams in this course. Instead of the exams, every student has to participate in lectures at least 80 %, perform a lecture, act as an opponent, participate in measurement exercises and write and present the results of a pre- study about a given subject.
Sessions:
1. General topics, 22.3.
2. Student lectures & possible Guest lecture by Jeroen Doggen, Artesis Hogeschool Antwerpen, 12.4.
3 Student lectures 19 4
JPR 22.3.2010 3. Student lectures, 19.4.
4. Student lectures & practical location measurements, 26.4.
5. Student lectures & practical location measurements, 3.5.
6. Presentations of pre-studies, 10.5.
Student Presentation Topics
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1. Basic methods (e.g. TOA, TDOA, EOTD, AOA, RSS(?))
RSS(?))
12.4.2010, 2 students (nn1-2)
2. Satellite positioning (GPS, Galileo, Glonass, pseudolites, etc.)
12.4.2010 (OR19.4.2010), 2 students (nn 3-4)
3. Mobile positioning (GSM/UMTS)
19 4 2010 2 students (nn 5-6)
19.4.2010, 2 students (nn 5-6)
4. Short-range location techniques such as UWB, RFID, WLAN, Bluetooth, ZigBee, Ultrasound, etc.
19.4.2010 & 26.4.2010 & 3.5.2010, 4 students (nn 7-10)
Student Lectures
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Every student has to make a lecture on a given topic and perform it in the appointed date. The student group itself is responsible for planning the given entity and dividing the topics for it’s members planning the given entity and dividing the topics for it s members.
The material for the lesson should be sent to the teacher and to the opponent in electrical format (Power Point is preferred) by email on Friday afternoon at 16.00 p.m. before the lecture
The topics will be shown to you in a list. Build up the groups and reserve your topics, first lectures should be given after one week or 2 weeks (if the course will be postponed with 1 week)
The lecture should last at least 30 minutes. After that there will be
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15 minutes reserved for the comments and questions of the opponent and also other students.
Student must also give a self-evaluation with good explanation to the teacher e.g. by e-mail.
The Opponent
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The task of the opponent is to read the material in advance and then at the presentation to ask clarifying questions that help the audience to understand the topic
audience to understand the topic.
The opponent will receive the lecture material by e-mail latest at 16.00 pm Friday before the lecture.
The opponent is also expected to give more detailed feedback on the presentation than the rest of the audience.
The opponents for different topics will be drawn out of the hat.
The opponent must also give his own evaluation of the lecture in scale 1-5 also with reasons
scale 1 5, also with reasons.
Also the performing in the role of the opponent affects the
assesment of the student.
The Contents of the Student’s Lectures
(Basic methods)
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The lectures should include at least the following s bjects
subjects:
General description
The main principle (e.g. examples of calculating the position)
Technical features of the technology/method
Ad t d di d t f th
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Advantages and disadvantages of the technology/method
The most common applications (very shortly)
The Contents of the Student’s Lectures
(Satellite positioning, mobile positioning, short-range location technologies)
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The lectures should include at least the following s bjects
subjects:
General description
The main principle shortly
Technical features of the used method
Advantages and disadvantages of the t h l / th d
technology/method
The most common applications
The practical location measurement exercises
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The students will be divided into two groups
T i d f th t (
Two sessions reserved for the measurement (one system/session)
1.
Nanotron system (based on chirp technology)
2.
Lost system by Essensium
Tasks for groups
Plan the tests to measure the system performance
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y p
Execute the planned tests
Analyse the results and create the report
Belgian students will guide you to use those systems
Pre-study Topic by Kari Kivistö
12
Course Material
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All materials for this course will be available in the home page of the Telecomm nication Laborator home page of the Telecommunication Laboratory:
http://www.tekniikka.oamk.fi/tl-lab
You can access the page with your student username and password.
The student lectures will be published in these pages
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as soon as the teacher receives them.
Assessment of the Course
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Main part of the assessing happens on the base of the lecture and the pre-study: p y
Teacher’s evaluation (the lecture and the pre-study)
Opponent’s evaluation (the lecture)
Self-evaluation (the lecture)
Also the performing as an opponent is evaluated by the teacher (from - - to ++) and has an effect on the grade
Active participation in practical measurement exercises
A student must attend at least 80 % of the course hours to pass the course
Scale is 0-5
General Aspects of Location Technologies
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Introduction
1 F d l d T
1. Fundamentals and Terms 2. Basic Measurements
3. Basic Technology based Applications
Satellite positioning
Mobile positioning
Short-range location techniques
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Introduction
The basic task of a wireless communication system?
I f i f
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Information transfer
Nowadays also location information is often needed
Personal safety
Industrial monitoring and control
Asset tracking
Commercial purposes etc
Commercial purposes etc.
1. Fundamentals and Terms
Distance measuring
To determine the radius of a circle or of a sphere
17
p
May be used to compute locations
Location (”where is it?”)
Point in space which is described as a symbolic place (e.g. a room or street) or as a set of coordinates defined as distances or angles in relation to another point
Position generally synonymous with location
Positioning
Positioning
Process of finding the two or three-dimensional coordinates of a terminal
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Fundamentals and Terms (cont.)
Range
The greatest distance between two terminals over which communication is
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g supported
May be used also as any distance between terminals that has been calculated by distance measurement or location techniques
Multilateral
The target is a transmitter whose location is calculated from measurements taken by multiple fixed terminal receivers whose positions are known
e.g. cellular positioning
Unilateral
The target receives transmissions from multiple terminals, whose positions are known, and calculates its own position
e.g. GPS
Fundamentals and Terms (cont.)
Navigation
The determination of the position and velocity of a moving vehicle
19
p y g
Accuracy
Refers to how much the estimated position is deviated from the true position (e.g.
1 m accuracy)
Precision
An indication of the repeatability of a measurement
Defines the percentage that a certain accuracy (or better) is achieved (e.g. 95 % i i )
precision)
Resolution
The smallest readout intervals
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Fundamentals and Terms (cont.)
Lateration
Location determination from multiple
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p distance measurements
Trilateration (position is derived from the measured or given lengths of the three sides of the triangle)
Angulation
The use of angle or bearing data relative to points of known position to find target’s location
Triangulation
2. Basic Measurements
There are three basic properties that enable distance measurement and location from analysis of specific physical charasteristics of radio signals:
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1. Received signal strength (RSS) 2. Time of flight (TOF)
3. Angle of arrival (AOA) or direction of arrival (DOA)
All methods of distance measurement and location are derived from the measurements above, alone or in combinations. There are two variants of these methods that differ enough from the normal cases:
these methods that differ enough from the normal cases:
4. Proximity 5. Fingerprinting
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2. Basic Measurements (cont.)
1. Received signal strength (RSS)
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Signal level is used to estimate the distance
Signal level depends on the distance between the modules
The power density of an electromagnetic wave is propotional to transmitted power and inversely propotional to the square of the distance to the source
Accuracy vary according to different environments. Many aspects affect the signal: multipath fading, buildings, weather …
The attenuation that is caused by other means than increasing the distance is calculated and tried to be separated with mathematical models
2. Basic Measurements (cont.)
2. Time of flight (TOF)
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The distance between a transmitter and receiver equals the time of flight (propagation time) of the transmitted signal times the speed of
propagation
The distance can be determined from measurement of time of arrival (TOA) of a signal at the receiver when transmission time is known or from differences of reception time at different locations (time difference of arrival, TDOA)
Another expression of TOF is the phase of the received signal which may
Another expression of TOF is the phase of the received signal, which may be referred to as phase of arrival (POA), since phase may be related to time and distance through the signal wavelength and speed of light
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2. Basic Measurements (cont.)
Time of arrival (TOA)
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Time of arrival data from two base stations will narrow a position to two circles and data from a third base station is required to resolve the precise position with the third circle when matching in a single point. There are many ToA-based localization systems, including GPS.
The drawback of TOA is that it requires an expensive monitoring equipment (LMU) to maintain accurate synchronized clocks in all stations participating in the measurements.
2. Basic Measurements (cont.)
Time difference of arrival (TDOA)
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The process of locating an object by accurately computing the time difference of arrival (TDOA) of a signal emitted from the object to three or more receivers.
In unsyncronised networks the
measurement has to be done from time differences
Need for transmission that has a recognizable unambiguous starting point
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2. Basic Measurements (cont.)
Enhanced observed time difference (E-OTD)
Th bil th b d ti
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The mobile measures the observed time differences of received signals from pairs of base stations in known locations. The method is the same as in TDOA but the measurement is done by the mobile.
The terminal must be capable of contacting many base stations and calculating the location from time differences in signals or sending the information to server in the sending the information to server in the network
At least three base stations are measured to obtain the exact position
2. Basic Measurements (cont.)
3. Angle of arrival (AOA) or direction of arrival (DOA)
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direction of arrival (DOA)
Directional antennas are used to estimate the angle from which the signal arrives.
The angle of arrival may be determined to be the point in the pattern rotation where the signal strength is maximum (knowledge of g ( g transmitted power is not needed).
At least two estimates are needed.
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2. Basic Measurements (cont.)
4. Proximity
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Refers to detection of a mobile terminal as being within radio range of a fixed location so that the mobile is known to be within an area around that location
2. Basic Measurements (cont.)
5. Fingerprinting
l b h f l l
29
Locates terminal by comparing various characteristics of a signal or signals received at or from that terminal with a database of the same type of characteristics that has been compiled in advance over a given area or volume
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3. Basic Technology based Applications
There are three basic categories for location technologies:
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There are three basic categories for location technologies:
1.
Satellite positioning (GPS, Galileo, Glonass, pseudolites, etc.)
2.Cellular handset location (GSM/UMTS)
3.
Short-range location techniques (UWB, RFID, WLAN, Bluetooth,
ZigBee, Ultrasound, etc.)
3. Basic Technology based Applications (cont.)
Performance parametric measures of location identification:
Accuracy
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Accuracy
Calibration
Responsiveness
Scalability
Cost
Power consumption P i
Privacy
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3. Basic Technology based Applications (cont.)
1.
Satellite positioning (GPS, Galileo, Glonass, pseudolites, etc.)
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GPS (the Global Positioning System) is a network of 24 Navstar satellites orbiting Earth at around 20 000 km
Originally established by the U.S.
Department of Defence (DOD) at a cost of about US$13 billion, A t GPS i f t ll
Access to GPS is free to all users, including those in other countries.
3. Basic Technology based Applications (cont.)
The system’s positioning and timing data are used for a variety of applications 33
are used for a variety of applications, including air, land and sea navigation, vehicle and vessel tracking, surveying and mapping, and asset and natural resource management.
With military accuracy restrictions partially lifted in March 1996 and fully lifted in May 2000
The DOD keeps 4 satellites in reserve to
l d t d d f ti
replace any destroyed or defective satellites. The satellites are positioned so that signals from six of them can be received nearly 100 percent of the time at any point on earth.
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3. Basic Technology based Applications (cont.)
GPS provides specially coded satellite signals that can be processed in a GPS 34
signals that can be processed in a GPS receiver, enabling the receiver to compute position, velocity and time.
Basically GPS works by using four GPS satellite signals to compute positions in three dimensions (and the time offset) in the receiver clock. So by very accurately measuring our distance from these satellites a user can triangulate their position anywhere on earth position anywhere on earth.
3. Basic Technology based Applications (cont.)
GLONASS
GLONASS is the Russian satellite 35
GLONASS is the Russian satellite navigation system. The system was declared fully operational on 18 January 1996 but by late 1997 only 15 satellites were available for navigation due to quality issues and funding problems.
Altogether, there should be 24 satellites in three orbital planes. Initially, system completion was planned by the year completion was planned by the year 2012, but with close attention from the Russian government, the system may be deployed in full scale by the end of 2009.
Accuracy of few tens of metres
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3. Basic Technology based Applications (cont.)
Galileo
A l b l i ti t llit t 36
A global navigation satellite system currently being built by the European Union (EU) and European Space Agency (ESA).
On 30 Nov 2007 the 27 EU
transportation ministers involved reached an agreement that it should be operational by 2013
Should be accurate down to the metre range including the height (altitude) above sea level
30 satellites, orbital altitude 23 222 km
3. Basic Technology based Applications (cont.)
2. Cellular handset location (GSM/UMTS)
There are various means of mobile positioning which can be
37
There are various means of mobile positioning, which can be divided into two major categories - network based and handset based positioning. The purpose of positioning the mobile is to provide location-based services (LBS), including wireless emergency services.
Location service: A service that is producing the location information
Location-based service: A value-added service which is utilizing
l i i f i
location information
Location-aware service: A service that is based on location service and which is modifying its functioning or content according to users location
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3. Basic Technology based Applications (cont.)
Location-based Mobile Applications
http://www.youtube.com/watch?v=qZlc_x6amaQ(Search and locate part 1)
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p // y / q ( p )
Governmental
Safety and security
Operator-based
Traffic and logistics
Entertainment and socializing
Miscellaneous
3. Basic Technology based Applications (cont.)
Governmental
US FCC ruled in 1996, that in wireless
39
networks the location accuracy for emergency calls must be (in the end of year 2005)
50 m for 67% of calls, 150m for 95% of calls for handset-based solutions
100 m for 67% of calls, 300m for 95%
of calls for network-based solutions
Also in Europe location services are
d f diff i
used for different purposes in emergency services
Military applications:
Military intelligence
Force tracking
Surveillance of citizens
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3. Basic Technology based Applications (cont.)
Safety and security
Criminal tracking: tracking people that are on parole or on vacation
40
g g p p p
from prison
Crime and terrorist attack prevention. Also lawful interception can be combined to positioning
Asset tracking: following money or important papers which are transported
Family monitoring: keeping an eye on children or elderly family members http://www.youtube.com/watch?v=hZKfNRxdUeI&NR=1 (ChildLocate)
(ChildLocate)
3. Basic Technology based Applications (cont.)
Operator-based
Location-specific billing: e.g. cheaper calls at home or office than
41
p g g p
out in the city
Network planning purposes
Parameter settings, e.g. handover thresholds and network demand monitoring
Network maintenance
Enhanced call routing
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3. Basic Technology based Applications (cont.)
Traffic and logistics
Traffic information; Traffic jams,
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j accidents, roadworks etc.
Tracking of stolen cars
Fleet management: trucks, taxis, ships etc.
Manpower planning: positioning the nearest service man
Car navigation: route planning
d i f i
and map services for moving vehicles
3. Basic Technology based Applications (cont.)
Maritime applications: security and logistics
Public transportation: real-time controlling of the functioning of
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buses, trains and local timetable information
Vehicle tracking for security and logistics purposes. For example work orders and instructions may be given according to accurate location of the vehicle or the employee
Road information: access to digital road data system based on actual location
Towing service for broken cars or the nearest garage
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3. Basic Technology based Applications (cont.)
Entertainment and socializing
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Entertainment and socializing
Social applications: e.g. Whrrl GPS Social Discovery http://www.youtube.com/watch?v=UkPZO717zvY&NR=1
Find-a-friend services, dating services
Location-based network games, e.g. geocaching:
http://www.youtube.com/watch?v=fp4oZhUzfWM
Useful tourist information, e.g. restaurants, theatres and other leisure time activities based on Your own location
3. Basic Technology based Applications (cont.)
Miscellaneous applications
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Miscellaneous applications
Dog radar:
http://www.youtube.com/watch?v=RAs8e4c4IYw
Advertisements, special offers,…
Location-based Yellow Pages
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3. Basic Technology based Applications (cont.)
Requirements for Mobile Location Methods
Good accuracy
46
Good accuracy
Positioning area should be global
Short positioning time
As small amount of signaling in the network as possible
In mobile station: power, size and price should be minimized
Consumer should be able to keep his privacy and disable the service
Ability to locate a large number of mobiles at the same time
Ability to locate all mobile devices
Conclusion: There is no single method that is suitable for all applications. Several location methods have been developed for different purposes.
3. Basic Technology based Applications (cont.)
Methods
Cell-ID
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TA: Timing advance
RSS: Received signal levels
RTT: Round trip time
AOA: Angle of arrival
TOA: Time of arrival
TDOA: Time difference of arrival
E-OTD: Enhanced observed time difference
E-OTD: Enhanced observed time difference
OTDOA: Observed time difference of arrival
A-GPS: Assisted GPS
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3. Basic Technology based Applications (cont.)
Accuracy of different mobile positioning methods
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Rural
Urban
Heavy urban
GPS AGPS DGPS Heavy urban
Indoor
0,001 0,01 0,1 1 10 100
Accuracy/km
3. Basic Technology based Applications (cont.)
3. Short-range location techniques (UWB, RFID, WLAN, Bluetooth, ZigBee, Ultrasound, etc.)
49
ZigBee, Ultrasound, etc.)
Typical characteristics
Low power and small terminals
Short distances (typically <100 m)
Short TOF => time resolution needed around 10 ns (equivalent of 3 m range)
Indoor environment (NLOS, severe multipath conditions)
Usage of unlicenced bands => interference from other system signal types
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3. Basic Technology based Applications (cont.)
The position methods mostly used for the short-range wireless networks are TOA, RSS and fingerprinting
50
Proximity detection is also used but can be considered as form of RSS
Multipath propagation may cause large deviations of the estimates from the true values
Fingerprinting requires the creation of a database that is individual for each site to be covered (changes require updating the database)
Movement of people at the site may affect accuracy
3. Basic Technology based Applications (cont.)
WLAN positioning
Most solutions are based on signal strength
51
g g
There are two possible methods used based on signal strength
The empirical model is based on storing pre-recorded measurements in a database
The propagation model is based on the degradation of the signal strength of a radio wave over distance in space
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3. Basic Technology based Applications (cont.)
Empirical model (fingerprinting)
An RF map is created before location positioning can begin 52
This map stores the signal strengths at each particular location from all access points that can be read from that area into a database
When a device requests a location, it sends the signal strengths from all access points to the server, which holds the database
The server now searches the database to find the closest match and returns this match as a location
Requires a large amount of manual effort before positioning can begin
Cannot be improved beyond a certain point by increasing the granularity of the grid, because the variations in signal strengths becomes too small
The time of the day when the RF map is created is of vital importance, since the radio wave properties in an indoor environment vary greatly depending on the number of people etc. in the building
A solution to this problem could be to create several RF maps and choose the appropriate one
Even taking all this into account, the empirical model is more accurate than the
3. Basic Technology based Applications (cont.)
Propagation Model (RSS)
The propagation model is based on the fact that as a radio wave travels through an i t it l i l t th
53
environment it loses signal strength
The amount of signal strength that the radio wave loses is dependent on the environment
The loss of signal strength is modelled by using given models, e.g. the hata-okumura model
Using one of these models, the distance from a wireless device to an access point can be determined by the signal strength loss over space
By calculating the distance to three or more access points, triangulation can be used to determine the location of the device
Can determine position with fairly good accuracy, given a reasonable proximity to the access points
Accuracy decreases as the distance between the device and the affiliated access point increases
One solution to this is to give the primary access point a higher weight in the triangulation algorithm
The accuracy of the propagation model can be improved by increasing the complexity of the model used
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3. Basic Technology based Applications (cont.)
UWB positioning
UWB has several features that differentiate it from conventional narrowband
54
systems:
Large instantaneous bandwidth enables fine time resolution for network time distribution, precision location capability, or use as a radar.
Short duration pulses are able to provide robust performance in dense multi-path environments by exploiting more resolvable paths.
Low power spectral density allows coexistence with existing users and has a Low Probability of Intercept (LPI).
Data rate may be traded for power spectral density and multipath performance.
UWB has good obstacle penetration capability compared with the existing transmission
UWB has good obstacle penetration capability compared with the existing transmission media.
UWB-based tracking systems are capable of locating objects within a building to an accuracy of 10-15cm in 3D.
http://www.youtube.com/watch?v=_7SqZ44yt0U
3. Basic Technology based Applications (cont.)
RFID positioning
A Radio Frequency Identification (RFID) system consists of two components: the
55
q y ( ) y p
Tranceiver (a transmitter and receiver in one), often called the Reader and Transponders (from transmitter and responder), often called the Tags.
If three or more readers receive the signal from one particular tag, the tag's position can be calculated by triangulation of the signal to the different readers. Each tag's position is calculated in the central computer, not in the tags.
The range in which readers and tags can communicate with each other is very limited
RFID technology can be used together with other positioning technologies (e.g.
UWB)
http://www.youtube.com/watch?v=QkSloRDs4j4
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3. Basic Technology based Applications (cont.)
Ultrasound positioning
Ultrasound positioning is a technique for estimating the position of a mobile
56
p g q g p
device using ultrasound signals from beacons.
Typical accuracies of ultrasound positioning systems are around 10cm; less accurate than advanced motion capture systems but more accurate than GPS.
Ultrasound is detected by microphones placed in rooms where the tracking is to be done. When ultrasound signals—which have short wavelengths—are emitted, the walls and doors confine the signals to that room.
3. Basic Technology based Applications (cont.)
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JPR 22.3.2010
RFID http://www.youtube.com/watch?v=QkSloRDs4j4 http://www.youtube.com/watch?v=h4STc5fM5Ss
UWB http://www.youtube.com/watch?v=_7SqZ44yt0U 58
GALILEO http://www.youtube.com/watch?v=iF7a_4vaGzc
Indoor precision location system by CSIRO http://www.youtube.com/watch?v=3fLJWDnv7rI http://www.ict.csiro.au/page.php?did=67
Indoor position (doc)
http://images.google.fi/imgres?imgurl=http://www.csd.uwo.ca/~nplemieu/thesisProposal/thesisProposal_fi les/image002.jpg&imgrefurl=http://www.csd.uwo.ca/~nplemieu/thesisProposal/
Miikka Kiprusoff http://www.youtube.com/watch?v=_gfXty29k7Q&feature=related
"Local Positioning Systems"by Krzysztof W. Kolodziej, Johan Hjelm. Hardcover 488 pages. ISBN:
0849333490
http://www.youtube.com/watch?v=6kJgN25gfgg&feature=related(Bluetooth positioning)
http://www.youtube.com/watch?v=Zb-t6vPNRrQ&feature=related(pelastustoimi)
http://www.youtube.com/watch?v=9HsBtdeh97c(ICDNET)
