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					 An Ultra-Wideband Location
Positioning Navigation System
     for Mobile Robotics




        James Knox (B0036062)
        Supervisor : Dr J Condell




        Final Report (EEE521M4)
               April 2008
Abstract

There is considerable interest in the development of real time location systems
(RTLS) for industry. The ability to track the real-time location and movement of items
or people offers a range of useful applications in areas such as safety, security and
the supply chain. Current location determination technologies have limitations that
heavily restrict how and where these applications are implemented, including the
cost, accuracy of the location, calculation and inherent properties of the system.


Real-time Ultra Wide Band Location determination is a technology that uses Ultra-
wideband (UWB) to locate with precision a device in space and time. This real time
location system can deliver very high positional accuracy in harsh industrial
environments that previously caused problems for traditional location systems based
on Wi-Fi of RFID due to interference. Ultra Wide Band systems work by being able to
calculate the location of tags which are designed to be mounted on assets or to be
worn by a person. They transmit UWB signals that are received by sensors which
contain an array of antenna and ultra-wideband radio receivers. The data from these
sensors combined with dedicated software uses algorithms to work out the angle of
arrival (AOA) of the UWB signal from the tag which is then compared to the time
difference of arrival (TDOA). This information is determined between pairs of sensors
connected by timing cables.      The combination of AOA and TDOA measurement
technologies delivers a precise three dimensional location system that is powerful,
reliable, robust - specifically designed for harsh industrial environments.

This new technology can locate with precision items in 3D space and opens up a
new world in interactive applications especially within the robotics industry. This
thesis examines the use of ultra wide band technology in tracking robots.




                                            2
Table of Contents

Abstract ............................................................................................................................... 2
Table of Contents .............................................................................................................. 3
Table of Figures................................................................................................................. 5
Tables.................................................................................................................................. 7
Graphs ................................................................................................................................ 8
Acknowledgments ............................................................................................................. 9
1 Introduction ............................................................................................................... 10
  1.1 Aims ...................................................................................................................... 10
  1.2 Objectives ............................................................................................................ 11
  1.3 Overview of Thesis............................................................................................ 11
2 Literature Review..................................................................................................... 13
  2.1      Global Positioning Systems ......................................................................... 13
  2.2      Indoor Positioning .......................................................................................... 15
    2.2.1 Wi-Fi (802.11) Based Indoor Positioning ................................................ 15
    2.2.3 Ultra-Wideband location ........................................................................... 17
  2.3     Robotics and Location Determination .......................................................... 19
    2.3.1 Robotic Navigation Sensors ...................................................................... 20
  2.7 Conclusion......................................................................................................... 22
3 Requirements Specification and Analysis ............................................................. 23
  3.1     Problem Specification ..................................................................................... 23
  3.2     System Scenario ............................................................................................. 23
  3.3     Requirements Analysis ................................................................................... 23
    3.3.1         Functional Requirements ....................................................................... 23
    Client Side ................................................................................................................ 23
    Server Side ............................................................................................................... 24
    3.3.2         Non-Functional Requirements .............................................................. 24
  3.4 Hardware and Software Requirements ......................................................... 24
  3.5 Development Languages ................................................................................. 24
  3.6 Conclusion......................................................................................................... 25
4 System Functionality: Order of Proceedings ...................................................... 26
  4.1 HCI principles..................................................................................................... 28
  4.2 Interface Design ................................................................................................ 28
  4.3 Platform Control and Location Engine Configuration .................................. 29
  4.4 Sensor properties .............................................................................................. 29
  4.5 Conclusion ........................................................................................................... 30
5 Design and Implementation ................................................................................... 31
  5.1 System Structure ............................................................................................... 31
  5.2 Implementation .................................................................................................. 32
  5.3 DHCP Software ................................................................................................. 33
    5.3.1 DHCP Log .................................................................................................... 34
  5.4 Location Engine Configuration ........................................................................ 35
  5.5 Calibration of Sensors ...................................................................................... 36
  5.6 Sensors scanning area plan ............................................................................ 38
  5.7 Transmitting tags ............................................................................................... 39
  5.8 Location sensors in operation ......................................................................... 39
  5.9 Conclusion .......................................................................................................... 43


                                                                    3
6   Testing ...................................................................................................................... 43
  6.1 Location Testing ................................................................................................ 43
  6.2 Calibration Testing ............................................................................................ 44
  6.3 Error Tracking Testing ...................................................................................... 44
  6.5 Conclusion ........................................................................................................... 47
7 Evaluation ................................................................................................................. 48
  7.2 Evaluation Results ............................................................................................ 50
  7.3 Evaluation results of tag location test. ........................................................... 50
  7.4 Evaluation results of water test. ...................................................................... 51
  7.5 Evaluation results of material test. ................................................................. 52
  7.6 Evaluation results of other tests carried out .................................................. 53
  7.3 Conclusion ........................................................................................................... 57
8 Project conclusion ........................................................................................................ 58
9 Potential Future Work ................................................................................................. 60
References ....................................................................................................................... 61
Appendix A ....................................................................................................................... 64
Test results on how a liquid can effect a tags location and detection. ................... 64
Appendix B ....................................................................................................................... 69
Test results on how different materials effect a tags location and detection. ........ 69
Appendix C ....................................................................................................................... 81
Results from tracking a person wearing a tag from point A to point B. .................. 81
Appendix D ....................................................................................................................... 86
Results of tests carried out on the accuracy readings of a tags location. .............. 86
Appendix E ....................................................................................................................... 93
Test results: Liquid disturbance test............................................................................. 93
Appendix F ....................................................................................................................... 95
Test Results: Three tags transmitting at the one time. ............................................. 95
Appendix G....................................................................................................................... 97
Configuration and setup of the location detection system ........................................ 97
Appendix H ....................................................................................................................... 98
Problems with the setup and configuration of the location detection system ........ 98
Appendix I....................................................................................................................... 100




                                                                 4
Table of Figures
Figure 1: GPS Satellites ................................................................................................. 14
Figure 2: Trilateration. Wikipedia (2008) ..................................................................... 14
Figure 3: Vicon animation .............................................................................................. 16
Figure 4: Vicon motion capture ..................................................................................... 16
Figure 5: Ubisense dealing with Multipath effects (Ubisense, 2008) ...................... 17
Figure 6: Ubisense compact tags, single sensors and series 7000 sensors......... 17
Figure 7: Car production line can be zoned using Ubisense (2008) ....................... 18
Figure 8: Bluetooth WI-FI and UWB Protocols (Shahril, 2008) ............................... 19
Figure 9: Wireless acoustic location with room-level resolution using ultrasound 20
Figure 10: Beacon navigation (Lee, 2008) .................................................................. 21
Figure 11: Beacon aided navigation for Robots ......................................................... 21
Figure 12: .NET Framework (Woods, 2008) ............................................................... 25
Figure 13: Use case diagram showing the functionality of the System .................. 26
Figure 14: State diagram for a Location Detection System ....................... 27
Figure 15: High-Level Sequence Diagram for Tracking RF tags. ........................... 27
Figure 16: Good Design Principles............................................................................... 28
Figure 17: Platform Control ........................................................................................... 29
Figure 18: Deployment of sensors ............................................................................... 29
Figure 19: Properties of the master sensor location.................................................. 30
Figure 20: Evolutionary Development .......................................................................... 31
Figure 21: Sensors wiring connection system ............................................................ 32
Figure 22: Diagram showing the Location Detection System Setup ....................... 32
Figure 23: IP Configuration settings of Laptop ........................................................... 33
Figure 24: IP Pool address edited to range from 192.168.3.7-10. .......................... 33
Figure 25: The DHCP Server software ........................................................................ 34
Figure 26: Ping request successful, confirms a working network connection ....... 34
Figure 27: DHCP log in Notepad .................................................................................. 35
Figure 28: List of Dynamic addresses and the Physical addresses of sensors .... 35
Figure 29: Location Engine Configuration – Sensor Status ..................................... 36
Figure 30: Location Engine Configuration – Sensor and Cells ................................ 36
Figure 31: Calibration of each sensor in progress ..................................................... 37
Figure 32: Thresholds set for the four sensors........................................................... 37
Figure 33: Sensors scanning area to be covered ...................................................... 38
Figure 34: Internal components of a Transmitting tag............................................... 39
Figure 35: Location of Tag at ground level at the centre of area plan .................... 40
Figure 36: Location of tag moved 1/2 meter back from centre towards the master
sensor at floor level on the area plan. .......................................................................... 40
Figure 37: Location of tag moved 1 meter back from centre towards the master
sensor at floor level on the area plan. .......................................................................... 41
Figure 38: Location of tag moved 1.5 meters back from centre towards the master
sensor at floor level on the area plan. .......................................................................... 41
Figure 39: Location of tag moved 2 meters form central location away from the
master sensor. ................................................................................................................. 42
Figure 40: Location of tag moved 1.5 meter form central location and 1 meter to
the right side..................................................................................................................... 42
Figure 41: Grid reference 1 m2 overlaid on the onscreen grid reference ............... 44


                                                                  5
Figure 42: A three-dimensional Cartesian coordinate system ................................. 44
Figure 43: Tracking error ............................................................................................... 45
Figure 44: Sensor location error zone ......................................................................... 46
Figure 45: Periodical broadcasts from the transmitting tag ...................................... 46
Figure 46: Centre point of floor plan marked out to scale......................................... 48
Figure 47: Plan to scale of area in cm ......................................................................... 49
Figure 48: Sensors in operation locating transmitting tag id: 010-000-015-099 ... 49




                                                             6
Tables
Table 1: User Use-Case Diagram Descriptions

Table 2: Advantages and disadvantages of different types of architecture

Table 3: Showing the event source, event class and event attributes

Table 4: Water test results (See Appendix A)

Table 5: Material test results (See Appendix B)

Table 6: Performance tests

Table 7: Water disturbance test results




                                          7
Graphs
Graph 1 Disturbance caused to a transmitting tags signal.

Graph 2 Disturbance caused to a transmitting tags signal.

Graph 3 The position before and after the basin full of water covers the
transmitting tag.

Graph 4 Position of the transmitting tag as it is moved further away from the
centre of the room. The reliability of the location detection system is effected by
how far the transmitting tags are from the central position covered by the sensors.

Graph 5 Shows how the error rate becomes more acute the further the tag is
moved from the central position in the room.

Graph 6: Shows the readings taken from a person wearing a transmitting tag
walking from point A in the room to point B in a straight line. See Appendix C

Graph 7: Error detection results see Appendix C for the screen shots




                                         8
Acknowledgments
I would like to take thank project supervisor, Dr Joan Condell, for all her advice,
guidance, constructive feedback support and encouragement throughout this
project.

I would also like to express my thanks to Dr Kevin Curran, for providing me with
the idea for this project, his guidance and support throughout the project’s
development and for providing me with help and assistance throughout the
semester.

I would also like to thank my family for their support and patience, friends and
work colleagues for their assistance. I would like to thank the staff at Magee
University for their help and assistance.




                                        9
1      Introduction
Location systems can be divided into two types. There are outdoor location
systems (an example of which is GPS) and indoor location systems. The overall
principle upon which these systems operate is to locate an object accurately.
There are various types of location systems some based on wireless others
based on Video imaging and digital location systems but they all have their
advantages and disadvantages. Outdoor location systems for example GPS are
costly to implement. The infrastructure required for these types of systems
include satellites and receivers. Their performance can be affected by weather
conditions and other atmospheric conditions and the accuracy which they deliver
is not as accurate as that of indoor location systems.

Indoor location devices still have some problems such as the ability to locate
objects exactly. This can be caused by a number of factors depending on the
system being used. Each system has its advantages and its drawbacks. Some
can provide a high degree of accuracy but are not suitable for manufacturing
businesses as they do not perform well in these conditions due in part to
interference caused by other machinery. The cost of some of these systems is
also a factor as they can be very expensive to implement. Scalability is another
issue that requires investigation. However in order to evaluate these systems we
must look at how the different systems operate, their advantages and
disadvantages. The benefits of being able to track objects accurately cannot be
underestimated. Industry and business have longed to be able to effectively track
objects, components, assets and people. Ultra Wide Band technologies are often
described as the next generation of real time location positioning systems. In the
world today industry is becoming more competitive and any technology which can
provide a competitive edge is welcomed and much sought after. However not all
technologies live up to their claims which can prove very costly to industry.
Therefore this research project investigates the use of a real time indoor
positioning system to guide robots in performing various tasks.


1.1 Aims
The aim of this project is to evaluate and test the accuracy, precision and
robustness of the location detection system over a small geographical area. This
will receive data that will be used to establish the locations in real time tags that
transmits signals. To achieve these aims we will install an Ultra Wide Band
(UWB) location detection system. This involves the wall mounting of sensors in a
square grid formation at ceiling height and the connecting of sensors with cat 5
network cables to a central Ethernet switch. Timing cables are also connected to
each sensor in sequence and then to a master sensor in order to achieve reliable
timing results. These cables are finally connected to a computer via a network
cable. The computer will have the software and licence installed to operate the
hardware. The projects aim is to identify how beneficial an indoor UWB location
detection system could be in the field of robotics and how industry could benefit
from this new emerging technology.



                                         10
Some Key design factors for Location systems are:

   Accuracy - How often does the system meet expected requirements.
   Affordability - Monetary cost.
   Scalability - How the systems can be extended.
   Resource requirements - Memory, computational capability, power.
   Privacy - Determine location without revealing confidential information.
   Portability - Easily adapt and modify to future technologies.
   Precision - How accurate the Location system is.



1.2 Objectives
The objectives of this project are to investigate, demonstrate and test the UWB
location detection system, the hardware performance and the software reliability,
to run tests under various conditions and to determine the accuracy of locating
and tracking tags using two way communications. We will test the dual radio
architecture and use the feedback from the timings and signals received by the
sensors to calculate the accuracy of the system for locating with the stated
degree of accuracy a tag at a certain position in time and space. Testing will
confirm the stated reliability of the tags under challenging environments, to
ascertain if the tags can withstand harsh environmental factors that may affect
their reliability compared with traditional location detection systems based on Wi-
Fi.


1.3    Overview of Thesis
The approach taken to the development of this project will consist of system
examining different location systems and how they are implemented with the
main focus being on how well the location detection system works. A literature
review will compare and detail the advances in this new emerging technology and
will include detailed information about real time location systems, their reliability
and how they can be successfully implemented. A review of similar applications
will be carried out to assess how the development of location detection systems
has been influenced by industry’s needs. Important design factors will be
assessed such as precision and limiting interference. The location detection
system will be analysed including the hardware and software that goes into the
complete system. Developments will be discussed within the field of robotics and
how they have an impact on the way we work, how they have changed industry
and the workplace. Investigations into system implementation, system testing,
system analysis and analysis of results will take place. This may involve areas
such as Networks and Programming, Human Computer Interaction (HCI),
Database Management and Wireless Technologies.




                                         11
Chapter 2 will provide the Literature Review which will investigate how this new
developing technology may benefit the robotics industry. Chapter 3 will provide a
requirement analysis detailing how a real time location system compares to
similar systems. The functional and non functional system requirements will be
investigated. Hardware and software requirements will also be examined. The
chapter concludes with a discussion on the future of this new technology and the
specific advantages and disadvantages of using real time location systems
compared to similar systems. Chapter 3 will examine the problem specification
and objectives of the system design processes and how these systems are used
within industry. It will look at the software and also aspects of Human Computer
Interaction (HCI). Story-boards screen shots will be used to portray the system in
operation and how these technologies are implemented.

Chapter 4 will focus on the Robotics design and how they can make use of
location detection systems. The architecture of robotics within industry will be
examined in detail.

Chapter 5 will focus on the design phase of the project. The architecture of the
system will be examined in detail concentrating on the hardware and software
that go into making up the system. Object oriented modelling will be shown
including diagrams that model the systems main processes.

Chapter 6 provides an overview of the implementation phase of the project where
we will see how algorithms are used to supply a visual representation of the
position of transmitting tags. Visual screen location grid display diagrams will be
used with the interface showing results of tag location. The areas under
discussion will be system setup and implementation, problems encountered and
how these were resolved. Results will be tabularised and appraisal of these
results will be summarised.

Chapter 7 will focus on performance and hardware testing of the system; different
methods of testing will be investigated to ensure that the results that the system
supplies are accurate, test cases of the application will be presented. Chapter 8
will provide an evaluation of the performance of the UWB real time location
system - how successful the project was, did it achieve the stated requirements in
terms of satisfying the projects remit? Finally, Chapter 9 will present a detailed
overall summary of the project and recommendations on how future work may be
influenced by this new and emerging technology.




                                        12
2      Literature Review
This chapter gives a brief overview of the history of location detection systems
from the earliest developments through to developments taking place today in this
field. Location systems can be divided into two types which are outdoor location
systems which include Sonar, VOR/DME Loran Radar and GPS. These types of
location systems are characterised by reference points deployed at known
positions. These types of systems use expensive infrastructure in the form of RF
ground stations and satellites that are used as reference points. The majority of
these systems employ RF signals to provide location information.

Indoor location systems are required to provide more accurate location detection
than outdoor systems and they often have to work in harsher environments. Often
RF signals are interfered with because of electromagnetic discharge from other
sources. Therefore indoor location systems still have problems to overcome
regarding the accuracy location detection. The preceding chapters we will be
examining various systems, how they work, the benefits that they can bring and
the problems that need solving. Ultra-wideband employs sonic detection methods
that help overcome many of the difficulties that other indoor location systems
suffer from, Ultra-wideband location detection system combines sensors and
transmitting tags to provide coverage of an area referred to as intelligent space,
this is where accurate information can be obtained about location of objects. The
robotics industry can benefit from advanced location detection systems, using a
combination of sensors and taking accurate measurements of a tagged robots
location, one can accurately predicted, with better accuracy the position of a robot
in relation to its surroundings. The accurate location of a robots position is
important to improve reliability.    Mobile robots will then be able to operate
autonomously in their environment, accurate prediction of location paths and
navigation direction will be achieved making them more useful productive and
reliable.


2.1      Global Positioning Systems
Global Positioning Systems (GPS) employ 24 satellites that are in fixed orbit
above the Earth and between them cover the entire Earth surface. GPS operates
by sending signals that travel at the speed of light from these satellites. Each
satellite has an atomic clock to ensure timing accuracy. Each satellite continually
transmits messages containing information relating to the time the message was
sent and the precise location of the satellite in orbit above the Earth's surface.
GPS uses a combination of three satellites and Trilateration to accurately locate
the position of an object. GPS is commonly used for vehicle navigation systems
and are accurate to approximately 15 metres. However the drawback with GPS
is that the satellite signals are not strong enough to penetrate inside most indoor
environments (see Figure 1).




                                        13
                             Figure 1: GPS Satellites

Trilateration (see Figure 2) is used to determine the exact position. This is similar
to triangulation, but with Trilateration three reference points are needed to find a
point on a 2D plane. The correct position of an object is found by calculating the
intersection point of the three spheres. A fourth satellite is required to measure
the time accurately. This combined with the information from the other three
satellites helps locate in time and space the location of a transmitting object.




                     Figure 2: Trilateration. Wikipedia (2008)

In the past GPS technology was the preserve of the Military who could afford it.
However recently the cost of development of GPS systems for example traffic
location systems have made the technology more universally accepted. GPS
technology can now be found in many appliances. For example Garmin is a
company that manufactures satellite navigation devices for a wide range of
customers. These include Motorists, motorcyclists, outdoors and fitness
enthusiasts as well as leisure users in the aviation and marine markets (Garmin,
2008). More established tracking technologies such as Global Positioning
Systems (GPS) generally do not work reliably indoors or, at best are not very
accurate indoors.




                                         14
2.2      Indoor Positioning
Indoor Positioning Systems (IPS) locates and tracks objects in buildings. These
may be pre-tagged objects, or discovered objects. Examples of tagged objects
are patients or equipment in a hospital. Examples of discovered objects are
people in burning buildings or soldiers on a battlefield. Global Positioning
Systems are not suitable to establish indoor locations, since their microwaves can
be scattered by roofs, walls and other objects. An IPS uses other radio
technology, infrared, or ultrasound, to overcome this limitation. Infrared and
ultrasound are useful in environments where wireless radio frequencies may
interfere with critical equipment
The interaction between workers, machines, tools, work areas, and the products
they’re manufacturing has a significant location component. Whether in the
automotive, aerospace, computers, semi-conductor, or manufacturing, Real Time
Location Sensor technology can deliver improved quality at a reduced cost to
make the manufacturing operations more competitive. An RTLS provides
location-aware support to workers improving quality by reducing errors (and
therefore reducing the cost of fixing them) and increasing efficiency by reducing
process execution times. The devices and tools used by the workers can be
made to know where they are and in which relation they stand to the production
materials.


2.2.1 Wi-Fi (802.11) Based Indoor Positioning
Sound navigation and ranging is a technique that uses sound propagation
(usually underwater) to navigate, communicate with or detect other vessels.
There are two kinds of sonar active and passive. Sonar may be used as a means
of acoustic location. Acoustic location in air was used before the introduction of
radar (Wikipedia, 2008). Radio Detection and Ranging, early systems were used
to detect metallic ships in dense fog but not its distance. During the Second World
War Britain exploited this technology as a defence system against German
aircraft attack to great effect. Radar was able to identify the range, altitude
direction, or speed of both moving and fixed objects such as aircraft, ships, motor
vehicles, weather formations, and terrain (Wikipedia, 2008). The Radar system
works by using a transmitter to emit radio waves that are reflected back by the
object that one is trying to locate. These signals are picked up by a receiver noise
and interference is then cancelled out. The accuracy of the signal received can
be accurately measured. Radar has many limitations. It is influenced by adverse
weather conditions that can distort readings. Readings can be misinterpreted, as
was the case during WW2 when the Japanese bombed of Pearl Harbour bringing
America into the war. The early warning radar readings were mistaken for a flock
of birds.

Wi-Fi positioning algorithms can analyse signal strength. One commercial
implementation is from Ekahau. The Ekahau RTLS system uses software based
location tracking to accurately track assets and people over any existing Wi-Fi
network. It does this by using algorithms to compute the location of tags which
have the Ekahau location protocol built in and use 2- way Wi-Fi signals to deliver
the required accuracy across a geographical area, without the need to install any
software or hardware in remote sites.



                                        15
The PlaceLab architecture is an example of an indoor positioning system. It is
made up of three elements. These are radio beacons in the environment:
databases holding beacon location information and PlaceLab clients that estimate
the location from these data (Curran, 2008). PlaceLab uses open source software
developed by Intel’s research center in Seattle and an 802.11 interface which
combine to predict location positions, It uses known positions that are stored in a
database that are combined with 802.11 signals to allow the system to establish a
users location. However when tested to find a users position in a relatively small
geographical area like a University Campus, it does not achieve very good
accuracy.

2.2.2     Camera Based Indoor Positioning
Vicon is a digital optical and video based motion tracking system that allows for a
better understanding of movement. By being able to track and analyse movement
it offers solutions to real life problems. This advanced optical motion capture
system consists of cameras, controlling hardware and software that is able to
analyse data and output the results in a meaningful way. Vicon offers high speed,
high resolution, interference-free, real-time tracking for engineering related
studies. Using video and digital optical tracking techniques, (Vicon, 2008). This
system is designed to be expandable and allow easy integration into the working
environment. The system allows for the accurate tracking of objects by use of
cameras, triangulation and software that allows users to analyse the data.




      Figure 3: Vicon animation              Figure 4: Vicon motion capture

A benefit of this system is that it does not use radio frequency (RF) which is
sometimes prone to metallic interference. It claims to be able to provide a
positional accuracy of better than 1 mm. An example of a Vicon system in
operation is to create graphical representation of the way humans walk. This is
achieved by attaching reflective markers to a human then using the video based
motion tracking system to collect data generated by recording of the reflective
markers position relative to the movement, displacement, velocity, and
acceleration of selected points on the lower and upper limbs. This data is then
analysed and the results can be displayed on a computer screen (see Figure 3).
This system can have benefits for the robotics industry, understanding movement
can advance how robots are designed and operate in a human like fashion (see
Figure 4).




                                        16
2.2.3 Ultra-Wideband location
Ubisense Ultra-wideband (UWB) is a radio technology that can be used at very
low energy levels for short-range high-bandwidth communications using a large
portion of the radio spectrum. Ultra wideband (UWB) has gained in popularity as
a new technology recently and has been the focus of much research and
development. UWB offers solutions to applications, such as see-through-the-
wall, security applications, family communications and supervision of children,
search and rescue, medical imaging, control of home appliances, which make
UWB an ideal candidate for wireless home network (Rashid, 2006). Research has
shown that anything that can offer business a competitive edge is quickly adopted
and usually benefits companies through improved productivity, greater
efficiencies and savings. For a technology to be commercially successfully, it
must address a real need (Ward, 2003).




       Figure 5: Ubisense dealing with Multipath effects (Ubisense, 2008)

Therefore it is essential to investigate and identify real world needs where
location awareness technology can make a difference. Ubisense provides a
breakthrough in the field of accurate 3D positioning (see Figure 5). It utilises
ultra- wideband in the field of Radio Frequency (RF) to deliver accurate 3D
positioning which is scalable and offers real time performance. This can be used
over a large geographical area, especially for in-building locations. Ubisense is
targeting its sensing and middleware technologies at a number of markets,
including healthcare, security, workplace productivity and military training
(Steggles, 2003).




   Figure 6: Ubisense compact tags, single sensors and series 7000 sensors



                                       17
The development and deployment tools make the system easy to design,
implement and maintain taking all these factors into consideration and the
benefits that can be achieved using this technology. Ubisense claims that with
this system, companies will benefit rapidly and have a speedy return in their initial
investment. This particular commercial implementation uses proprietary tags to
communicate with the series 7000 sensors (see Figure 6).

Ultra–wideband is a technology based on radio frequency which has been used
by to build real time systems that can provide a high degree of positional
accuracy, in real time to within 15cm. It can work in very harsh and challenging
environments where conventional RFID and Wi-Fi have experienced problems
with interference.




           Figure 7: Car production line can be zoned using Ubisense (2008)


Examples where Ultra–wideband is used and gives good positional accuracy
would be the car manufacturing industry. It has been used to identify proximity
detection between objects allowing a robot to correctly and automatically select a
tool required by a particular model of car without the need for human intervention
or the need to reprogram the robots computer every time a car model type varies.
This saves time and cost and increases efficiency as the car production lines do
not have to be stopped. Within a Manufacturing site, zones can be set up using
the sensors mounted on walls which can receive and evaluate low frequency
signals from the location tags. Sensors are grouped together in cells which, when
combined with other cells, can give coverage over a large area. Within each cell
there will be a master cell that controls the other cells and allows for a high
degree of positional accuracy, in real time (see Figure 7).

The comparison table below (see Figure 8) shows the different protocols used by
some location detection systems. From the table UWB has a limited nominal
range of 10 meters compared to Wi-Fi that has a nominal range of 100 Meters.
The advantage UWB has over Wi-Fi is that it is capable of working in
environments where due to interference Wi-Fi would be unsuitable.




                                         18
          Figure 8: Bluetooth WI-FI and UWB Protocols (Shahril, 2008)

2.3     Robotics and Location Determination
The definition of a robot is very broad. Robots will integrate methods drawn from
all areas of AI, including machine learning, vision, navigation, manipulation,
planning, reasoning, and speech/natural language processing. This includes
industrial robot manipulators, such as those used for pick-and-place, painting, or
welding operations, provide they incorporate all these three elements. Early
manipulators had neither sensing nor reasoning ability; they were pre-
programmed to execute specifics tasks (Bekey, 2005). Today most industrial
robots are equipped with a variety of equipment that allows the robots more
autonomy these include cameras, sensors and on board processors.

Today the control of many industrial processes i.e. manufacturing, production etc
use automation rather than humans. Automation has brought many benefits,
more choice and lower prices. Automation is used widely in the chemical, steel,
paper industries and within the car manufacturing industry. Many other industries
benefit from automation as it has led to increased productivity and product quality.
The successful introduction of robots into the car manufacturing industries has led
to increased interest into the field of robotics. Improvements have been made to
control systems to make robots more adaptive and mobile. Mechanisms have
been added to robots to increase their location awareness; one of these systems
uses ultrasonic sensors which we will investigate in this report.

For mobile robots operating in man-made environments the 2D world assumption
is usually sufficient, However, the use of ultrasonic sensors fitted to the gripper
i.e. sensor-in-hand systems, of a robot-arm in order to steer the arm adaptively
requires a full 3D world model (Smith, 2001).



                                        19
Current research in autonomous robot navigation focuses on planetary
exploration, mining, agricultural applications, fire applications and military
applications. In the last decade we have seen many satellites sent into deep
space in order to investigate planet surfaces and meteorites. These robots can
operate in environments that would be hostile to humans. The information and
data that these robots have gathered from the surfaces of planets has been
invaluable to scientists, trying to better understand our own planets origins.
There are various types of robots and the functions that they perform are as
varied as they are complex. A sensing robot is one type of intelligent robot which
can be defined as’ a robot which measures the surrounding environment and
uses the resulting data to modify its own work pattern and adapt to the
environment. (Ohba, 1992).

2.3.1 Robotic Navigation Sensors
Different sensors are used to extract meaningful information and measurements
that can help provide information about the robots environment. For an
autonomous mobile robot to operate successfully it requires three things:
perception of its environment, decision making capabilities and a way to execute
information received in a meaningful manner (for example path planning and
navigation to execute a goal i.e. moving from one position to another efficiently,
safely and successfully avoiding objects). This requires problem solving skills and
strategic planning together with navigational capabilities. The comparison table
(Figure 9) shows the different types of systems currently on offer for outdoor and
indoor location detection systems.




Figure 9: Wireless acoustic location with room-level resolution using ultrasound




                                        20
Exteroceptive sensors are used to obtain information from the external
environment. Robots can obtain information from their environment by using
cameras that along with software allow the robot to distinguish shapes and
recognise objects. Proprioceptive Sensors measure the robots internal workings,
for example the battery voltage level or it can measure the rotation of the robots
wheels to measure distance travelled. The advantages of mobility cannot be fully
exploited without the capability of navigating (Nehmzow, 2006).




                            Figure 10: Beacon navigation (Lee, 2008)

Sensors can provide lots of data that can be processed to provide meaningful
information. However without being able to accurately predict the robots exact
location at a given time then this data received from the sensors would be
unreliable and lead to errors. The goal for any location system is to be able to
provide accurate positioning information within a coordinate system. This will
allow a robot to move autonomously (see Figures 9 and 10).




               Figure 11: Beacon aided navigation for Robots




                                        21
Ultra wideband claims to be able to accurately locate a transmitting RF tag to
within 6 cm in intelligent space. This project will investigate the accuracy of these
claims and how this technology could be combined with the field of robotics’ to
accurately determine in real time a robots location in relation to its environment. A
robots environment can include many different geometric obstacles and terrain
conditions. In order to make accurate decisions not only does a robot require
sensors to detect obstacles for path planning but it also needs to know its exact
location, in order to benefit from the data it receives. Using Ultra wideband we
explore how this location accuracy can be achieved and how it can be applied to
the field of robotics. The Robots environment representation can range from
continuous geometric description to decomposition – based geometric map or
even a topological map. The first step of path planning system is to transform this
possible continuous environmental model into a discrete map suitable for the
chosen path – planning algorithm.

Location information can also be derived from analysis of data such as video
images, as in the MITSmart Rooms project. Pentland, A. (1995). Accurate object
locations can be determined in this way using relatively cheap hardware, but
large amounts of computer processing are required. Furthermore, current image
analysis techniques can only deal with simple scenes in which extensive features
are tracked, making them unsuitable for locating many objects in cluttered indoor
environments.


2.7    Conclusion
This project should demonstrate that the advantages of robotics cannot be fully
exploited without an effective location detection system, which will empower
robots to navigate autonomously in an intelligent space therefore increasing their
productivity and mobility. The Gantt chart in Appendix I outlines the project plan
for semester two. The plan includes key work and milestones.




                                         22
3 Requirements Specification and Analysis
This chapter will outline the problem at hand. The problem will be specified in
detail and an analysis of the functional and non functional requirements will be
made. Also included is the list of software and hardware required for successful
completion of the project. The programming languages to be used in the project
are also discussed.

3.1   Problem Specification
The research into location detection systems has shown that there are various
systems which provide location detection which include Wi-Fi, GPS and others.
However this initial research has indicated that under certain environments many
of these systems suffer interference, making their readings unreliable. Problems
which occur are:
 Inaccurate location information
 No real time data
 Susceptible to interference
 Not expandable
 Not flexible
 Expensive to implement
 Relies on third party hardware

3.2   System Scenario
The Ultra wide-band location detection system would allow automatic detection
and tracking of RF tags in a large indoor area e.g. warehouse environment.
Combining the tags with robotics would supply accurate location information. The
information could be combined with a database to allow robots to navigate more
independently with less human input therefore increasing their productivity.

3.3   Requirements Analysis
The requirements for this project are broken down into functional and non-
functional requirements. Also included is the hardware and software required to
successfully complete this project.

3.3.1 Functional Requirements
Functional requirements are statements of services the system should provide,
how the system should react to particular inputs and how the system should
behave in particular situations (Somerville, 2004).

Client Side
   1. View location of sensors on grid matrix
   2. Identify the sensors
   3. Calibrate the sensors
   4. Activate the RF tags
   5. Calibrate the tags




                                       23
Server Side
   1. The server should be a computer with optimum software and hardware.
   2. It will have a permanent internet connection.
   3. It will maintain a database of all known APs on campus.
   4. It will maintain location information of all clients and update this whenever
      possible.
   5. It will be able to display this information graphically.
   6. It will be able to send this info to the clients.
   7. It will have a fully functional GUI.

3.3.2 Non-Functional Requirements
The non-functional requirements are:
   1. The system will conform to defined HCI standards.
   2. The system shall have a pleasing interface and shall offer a robust and
      reliable service.
   3. The system should be flexible.
   4. The connection between the client and server should be permanently
      available.
   5. Response time should be as low as possible.
   6. The system should be portable.


3.4   Hardware and Software Requirements
The system will require the following hardware.
  1. A server to send and receive location information.
  2. An internet connection.
  3. A network of 802.11 access points.
  4. A laptop with a wireless NIC.
  5. A GPS with a serial connection for the initial stumbling (Mapping of APs)
      process.

Software applications that will be required are:
   1. A stable platform on which to run.
   2. Custom made applications for client and server.


3.5   Development Languages
A Database Management System (DBMS) allows the manipulation of data and
can perform various functions including: Retrieval of records that meet a certain
criteria, Cross-reference records in different tables, update records. It makes use
of Datasets which can be used in conjunction with mobile devices.

Relational Database Management System contains the relational database and
the software required to run SQL queries and manage users. It can also carry out
restores, backups and other tasks. Some examples of Relational Database
Management Systems include: Oracle, my SQL (Structured Query Language).
SQL is a standard programming language in which instructions can be provided
for manipulating data stored in a relational database.




                                        24
The Ubisense System consists of a .NET application Programming interface (API)
platform, written in C-Sharp, most other development is in C++. The system
consists of around 100,000 lines of C-sharp code and 1 million lines of C++ code.
Code based on the .NET framework can integrate on industry standards TCP/IP,
HTTP and XML for web services. The .NET framework is a development and
execution environment that allows languages and libraries to work together
seamlessly to allow the developer to create Window based applications that are
easier to build, publish and deploy. The .NET framework allows a programmer the
freedom of not having to worry about the subsystems because he never has to
access it directly that is because they are abstracted away from the Framework
classes (see Figure 12 below).




                   Figure 12: .NET Framework (Woods, 2008)



3.6    Conclusion
This chapter deals with the functional and non functional requirements. It looks at
various systems e.g. Ultra wide-band location detection system and lists the
hardware and software requirements that required for this system to function
properly. The chapter also investigates the different development languages.




                                        25
4       System Functionality: Order of Proceedings
This chapter will examine the system functionality. HCI principles will be
examined, good interface design and layout. How the software that controls the
location detection hardware is installed. The chapter will it will outline the
problems at hand. Also included will be use case diagrams and state diagrams
that will help explain some of the processes which take place.

The use case diagram in Figure 13: gives a simple bird’s eye view of the
functionality of the system.
                                                                  Activate
                                                                   Tag
       Assign
        Tag


                                                                Locate
                                                                 Tag




                                                          Update Details
            Load Software

        Figure 13: Use case diagram showing the functionality of the System

Use-Case Diagram are used to describe the primary actors and events and the
pre and post conditions (see Table 1).

    Use Case Name       Load Monitoring Software
Primary Actor           User
Data                    RF Tag ID,

Description             Loads up the Application software
Preconditions           Software must be installed
Post Conditions         Application software loads


Use Case Name           Assign Tag
Primary Actor           User
Data                    RF Tag ID,

Description             The user assigns a tag to an object or person.
Preconditions           The user must activate the tag.
Post Conditions         The tag table is updated

                    Table 1: User Use-Case Diagram Descriptions



                                            26
       Figure 14: State diagram for a Location Detection System

The diagram (see Figure 14) is a representation of the processes involved in a
RF tag being located and tracked.

High-Level sequence diagram showing the stages and the processes required to
track a RF tag (see Figure 15).




      Figure 15: High-Level Sequence Diagram for Tracking RF tags.


                                     27
4.1    HCI principles

The implementation of good HCI is very important in the design of an interface
because it promotes good practice for the development of application software.
By using a more a more consistent approach to software development it allows
for more productivity, therefore reducing development costs (see Figure 41).

HCI principles should always be adhered to good interface design and layout. A
screen should have common controls (e.g. the Help button) should be in the
same position on every screen, regardless of the screens main function. Colour
schemes and form layout should also be consistent. All Good HCI should aim for

      Consistency
      Compatibility with Users’ Expectations
      Flexibility and Control
      Explicit Structure
      Continuous and Informative Feedback
      Error Prevention and Correction
      User Documentation and Support
      Visual Clarity


4.2    Interface Design


 User                             User               Functions
 Goals           Interface        Actions            of the            Results
                 Component                           System
                 s




                                   Feedback


                         Figure 16: Good Design Principles

Well constructed web sites should adhere to the three clicks rule. This allows the
user to get to the information that they require in just three clicks. The three clicks
rule is important not only for web sites it should be applied to mobile devices also,
as it minimises the amount of information stored in short term memory. This
allows users to better retain and learn how to navigate a system.

Poor user interface causes increased mistakes in data entry and system
operation, inaccessible functionality, user frustration: low productivity and/or
under utilisation. Any well developed application should a clear, non cluttered
design, this will minimise the time that the user takes scanning the screen to pick
out relevant information required by them.


                                            28
4.3   Platform Control and Location Engine Configuration

When the software for the system initially loads the user is presented the Platform
Control this informs the user that connection to the Ubisense Core server has
been initialized and is up and running (see Figure 17).




                               Figure 17: Platform Control


The main user interface shows the position of the deployed sensors in a matrix
grid for configuration purposes. This will allow the user to visually reference the
sensors in relation to space (see Figure 18).




                        Figure 18: Deployment of sensors

4.4   Sensor properties

The Sensor properties interface gives the user information relating to the location
of the sensor about the X, Y and Z axis. The Yaw is the directional degrees at
which the Sensor is tilted towards the Fuducial Calibration Point (see Figure 19).


                                        29
               Figure 19: Properties of the master sensor location.

Users will utilize battery powered radio tags to be mounted on a robot or worn by
a person. These tags when activated will transmit RF energy to provide accurate
data that allows the location of the tag to be identified through the use of
triangulation. The Location engine includes software required for the sensors to
track battery powered tags, in real time. Configuration wizards are used to install
the software.

4.5 Conclusion
This chapter examines the system functionality. Use case diagrams give a view of
the functionality of the system. Tables show use cases and state chart diagrams
examine how a RF tag is located. A High-Level sequence diagram shows the
stages and processes required to track a RF tag.
HCI principles are examined as they contribute to good design of systems.
Interface usability and good design help create systems that users feel
comfortable using.
The location detection system interface software is examined as well as the
sensor software and how it functions.
.




                                        30
5     Design and Implementation
The aim of the project is to develop and test the accuracy of ultra wide-band
location detection systems and their ability to track in real-time location and
movement over a small geographical area. The hardware that will be used in this
project will be supplied by the company Ubisense which specialises in location
detection. The project will use battery powered radio tags and a cellular locating
system to detect the location of the tags. The cellular locating system will emit
precisely timed short bursts of RF energy to provide accurate triangulation of the
position of the transmitting tag.

This section of the report documents the design phase of the system life cycle.
UML and various diagrams are used throughout this section to visually illustrate
the overall system functionality and the relationships of its many components.
Firstly we consider the global design of the system.


5.1   System Structure
A clearly defined workflow model which graphically depicts the system’s
structures is important. The sequence of events, showing which actions take
place and what data passes between the various elements, gives the developer a
visual reference to aid in implementing the system (see Figure 20 below).


                            Concurrent activities

                                 Specification             Initial
                                                          version

          Outline               Development             Intermediate
         description                                      versions


                                 Validation
                                                        Final version



                       Figure 20: Evolutionary Development

In order to achieve a thorough and productive design phase, the many different
aspects of the proposed system need to be investigated and structured. For this
reason it is important to use an appropriate design methodology. While a number
of different process models are available we choose to use the evolutionary
based approach. With this approach a number of prototypes of the system are
developed. These prototypes can be discarded if some aspect of the system is
proving unworkable or can be developed further until a satisfactory system is
built. Figure 11 shows a graphical representation of this approach.




                                                 31
        5.2      Implementation
        The system had to be mounted at a recommended height of 3 meters above the
        floor level. The sensors were attached to the wall using brackets that were
        supplied. The sensors were then manoeuvred to point to a central location in the
        middle of the floor approx at a 45 degree angle ensuring a good line of sight. A
        spirit level was used to check that the sensors were all level before finally securing
        them to prevent roll. All four sensors were connected to an Ethernet switch using
        cat 5 network cables and one of the sensors was configured to be the Master and
        the other sensors slaves. A timing cable was connected from each slave to a
        cable port on the master sensor (see Figure 21).

                                                 Switch

                                                                                               Laptop




                                  Figure 21: Sensors wiring connection system

        After positioning of the of the location detection system the cables were connected
        via a switch to a laptop. Identification of the sensors was achieved and their
        location established on a grid matrix. This allowed calibration of the sensors in
        relation to the space which they monitored (see Figure 22).



                      Timing Cable


                        These lines represent
                        the Cat 5 Network
                        Cables from each
                        Sensor to the Master
                        sensor and then to the
                        Ethernet Switch                                             Laptop




Slave Sonar Sensors    Timing Cable        Fuducial Calibration Point   Ethernet Switch      Master Sensor


                  Figure 22: Diagram showing the Location Detection System Setup


                                                                  32
See Appendix H. for problems encountered when initially configuring and setting
up the system.


5.3   DHCP Software
The DHCP software required editing to see the laptop’s IP address which is used
to run the Ubisense software. Laptops IP address 192.168.168.6 (see Figure 23).




Figure 23: IP Configuration settings of Laptop

After configuring the DHCP software the Ubisense Location Engine was able to
pick up the IP Address of the laptop and issue dynamic IP addresses to the four
sensors. Editing of the Server Software code was required (see Figure24).




.
Figure 24: IP Pool address edited to range from 192.168.3.7-10.


                                        33
Third party DHCP Server software V1.6.4 was installed, this issued a dynamic
IP addresses for each sensor (see Figure 25).




                     Figure 25: The DHCP Server software

Verification of the IP addresses functionality was achieved by pinging each
address individually to ensure that packets of data were reaching the destination
host and were being returned within the local network time restraints (see Figure
26).




   Figure 26: Ping request successful, confirms a working network connection


5.3.1 DHCP Log
Figure 27 shows how confirmation was obtained from the DHCP log that correct
connections are established over the local network and that response to requests
are being received from the four client Ubisence sensors.




                                       34
Figure 27: DHCP log in Notepad

The screen shot below shows that the DHCP server has issued the dynamic IP
addresses and that they have been associated with the physical addresses of the
Ubisense sensors (see Figure 28).




Figure 28: List of Dynamic addresses and the Physical addresses of sensors

5.4   Location Engine Configuration

The locating engine performs the computation of coordinates for the locations of
Radio transmitting Tags in real time. These tags can be worn by people. This is
achieved through multilateration, which is the process of locating the tags by
accurately computing the time difference of arrival (TDOA) of a signal transmitted
from the tag to the four receivers mounted at each corner of the room. Locating a
Tag by measuring the TDOA of a signal transmitted from the tag and received by
the synchronised sensors allows for the accurate location of the tag to be
identified accurately in real time.

Location Engine Configuration in Figure 29 shows the IP addresses from
192.168.3.7-10 and the sensor status as running this indicates that all is correct in
the configuration of all four Ubisence sensors. This allows for the timing
synchronisation accuracy which allows each sensor to listen for the radio
transmissions by the tags Timing synchronisation is achieved by the timing cables




                                         35
that connect each       sensor   to   the    master   controller   sensor   id   no’s
00:11:CE:00:OF:56.




Figure 29: Location Engine Configuration – Sensor Status

A plan was devised of the area covered by the sensors and the identification
numbers of each sensor. Master sensor ID 00:11:CE:OF:56 controls the timing
for the other sensors which are connected to it (see Figure 30).




          Figure 30: Location Engine Configuration – Sensor and Cells


5.5   Calibration of Sensors

The sensors are calibrated to a central fuducial point on the floor; this reference
point is used to verify that the system is correctly set up. Addresses from each
sensor are relayed via the master sensor to the Location platform software which
is installed on the laptop. The software then constructs a grid diagram showing
the location of the sensors in relation to the space which they monitor.

Each sensor had to be individually calibrated to ensure that background noise
was eliminated. This is important as background noise could interfere with the
accuracy of the readings (see Figure 31).




                                        36
                Figure 31: Calibration of each sensor in progress

The calibration process allowed the thresholds to be set for each sensor, this
reduces interference. (see Figure 32).




                  Figure 32: Thresholds set for the four sensors




                                        37
5.6   Sensors scanning area plan

Figure 33 shows results of running the software after calibration to ensure that the
timing signals from the sensors were operating correctly and being able to scan
the area to be covered. This was performed before introducing the Tags in order
to reduce interference.




                 Figure 33: Sensors scanning area to be covered

As can be seen from Figure 26 above each sensor is scanning the area plan in
real time searching for a Transmitting tag. The master sensor coordinates the
timing signals of the scans to ensure synchronisation accuracy. When a radio tag
is introduced it will transmit a signal back to the sensors located at each corner of
the room. Algorithms are used to work out the difference between the timing
signals and the radio transmitted signal from the tags which are picked up by the
sensors. In this way the system accurately works out the location of the Tags to a
degree of accuracy claimed to be within 6 cm.

Factors that may affect the accuracy of the readings could be the temperature of
the room or the humidity of the room. Other factors may be reflection from objects
within the room or attenuation loss from the tags. Testing of the systems
performance under various conditions will allow the location accuracy claims
made by the manufacturers to be examined. Movement of the tags at various
speeds will be tested to see how fast the location data can be retrieved by the
system and the accuracy of that data.




                                         38
5.7   Transmitting tags

A transmitting tag is a device that is enabled with location technology, usually
small enough that it can be attached to assets or carried by people (see Figure
34).




                                                     Lithium Battery

              Figure 34: Internal components of a Transmitting tag

Real time location sensor tags can help locate people and assets. An example
could be where one can attach tags to company laptops so that alerts can be
obtained when the laptops leave the building without the authorized owner or
attach tags to school projectors so that one can track which classes have the
projector. Wall mounted sensors pick up the tags location as indicated by a red
dot (see Figure 28).


5.8   Location sensors in operation

Results of running the system in real- time, with tag number 010-000-015-099
located at the centre of the area plan are now discussed. The location of the Tag
is indicated by the red dot at the junction of the blue waves (see Figure 28).




                                        39
Figure 35: Location of Tag at ground level at the centre of area plan




Figure 36: Location of tag moved 1/2 meter back from centre towards the master
sensor at floor level on the area plan.




                                        40
Figure 37: Location of tag moved 1 meter back from centre towards the master
sensor at floor level on the area plan.

Blue wave signals become more intense and concentrated as the tag moves
away from the timing sensors 00:11: CE: 00: OE: 71 and 00:11: CE: 00: OF: 38.
(see Figure 37).




Figure 38: Location of tag moved 1.5 meters back from centre towards the master
sensor at floor level on the area plan.



                                      41
Tag is moved forward 2 meters from the central position and away from the
master sensor.




Figure 39: Location of tag moved 2 meters form central location away from the
master sensor.




Figure 40: Location of tag moved 1.5 meter form central location and 1 meter to
the right side.



                                       42
5.9    Conclusion
This chapter examines the system and how it operates. Screenshots show the
location detection software in operation identifying the position and location
transmitting tag id number 010-000-015-099.




6      Testing
This chapter will outline the various testing procedures that are required to ensure
the functionality of the system. Testing is important as it will help locate errors that
can interfere with the performance of the location detection system. Location
testing was important so that results from the computer screen could be
compared with the physical location of the transmitting tag; this is why the floor
area accurately marked out to scale. This allowed accurate comparison of results
on screen to the actual location of the tags position.

Equipment testing is important to ensure that all the components that contribute
to the correct operation of the location system operate as required. Failure in any
one element can have an adverse effect on the overall performance of the
system. All units that go to make up an effective system require testing faulty
cable can lead to system problems this which may have a knock on effect when
trying to install and configure the software for the system. Making sure that each
unit is working correctly at an early date in the installation can prevent many
difficulties at later stages.

6.1    Location Testing
Location testing is important as it allows the user to map the actual physical
location of the transmitting tag through measurements on the ground and
compare these with the onscreen location of the transmitting tags. This is
provided by a combination of scanning signals and timing signals from the
sensors which are cross-referenced to locate the transmitting tag and display the


                                          43
location as a grid reference point. Software is used to display the area covered by
the sensors and the point where the tag is located (see Figure 41).




      Figure 41: Grid reference 1 m2 overlaid on the onscreen grid reference

6.2    Calibration Testing
Calibration of the sensors is required to get correct readings of the area which
they cover. When this is complete the sensors will be able to pick up the precise
location of the transmitting tags when they are introduced to the area covered by
the sensors. The sensors locate the tags in three dimensional space from a
particular point in space. The basic directions in which one can move are
up/down, left/right, and forward/backward. Movement in any other direction can
be expressed in terms of just these three definitions. Time is often referred to as
the "fourth dimension". It is one way to measure physical change. It is perceived
differently from the three spatial dimensions in that there is only one of it, and that
one cannot move freely in time but can only subjectively move in one direction
(see Figure 42).




           Figure 42: A three-dimensional Cartesian coordinate system


6.3    Error Tracking Testing
All systems are comprised of smaller units that are required to function properly a
battery in a transmitting tag that is not fully charged may not have sufficient power
to transmit its location signal to the surrounding sensors and therefore supply
false readings. Errors can also result from environmental factors false readings
from reflective surfaces. In order to compensate for these environmental
displacement errors it is important to calibrate the sensor thresholds. To do this it
is important to set the “Disabled Radio” tag on the master of the cell and then


                                          44
calibrates the four sensors. This compensates for errors in the real environment,
the perpendicular distance and the angle between the sensors. The sensors
measure distances with different sensitivities as the distance and the angle of
transmitted tag signals varies (see Figure 43).




                                          Wall

  Sensor

                                            dm
              h                                           Transmitting tag
                        ø
                                                          Location
                               d


                               Grid ref: 1 meter square


                                   Figure 43: Tracking error


We can measure the distance error e(d). Distance d(m) is defined as the distance
from the wall mounted sensors to the transmitting tag located at a vertical
distance h and the horizontal d where the position of the tag. The error rate and
time calculations using of the position of the transmitting tag have shown that
depending on the location of the tag the accuracy of the results can be influenced
when deciding the exact location of the tag. Trilateration is employed by the wall
mounted sensors to locate the position of the transmitting tag. The drawbacks of
using this method are that the scanning signals from the sensors do not always
intersect at one point. Environmental factors can influence the readings through
reflections of signals from surface. Humidity may also cause interference.

Estimations of transmitting tag location from the results supplied by the sensors
compared with the real location of the tags position in relation to a measured grid
map of the area covered by the sensors indicate some discrepancies. This is
especially the case the further the transmitting tags are moved away from the
centre of the area being scanned. It shows that distance errors become
significantly greater the further the transmitting tag is positioned from the centre of
the area being covered by the sensors. There are areas beneath the sensors that
are dead zones where signals from the sensors do not register (see Figure 44).




                                                   Area scanned by Sensor




                                          45
                      Figure 44: Sensor location error zone

Figure 44 shows the area a wall mounted sensor scans. Testing has shown that
the area directly below the sensor is a dead area and transmitting tags placed
there are not picked up successfully by the sensor.



Transmitting Tag sending out periodical broadcasts of its location to the Sensors
(see Figure 45).




            Figure 45: Periodical broadcasts from the transmitting tag


Different types of architecture offer advantages and disadvantages some offer
better privacy while others offer better accuracy. With all location detection
systems there is always a trade off. One of the advantages of the Ultra wideband
location detection system is it accuracy and its scalability (see Table 2).




                                        46
    Table 2: Advantages and disadvantages of different types of architecture


6.5 Conclusion
This chapter examines the system, how it operates and problems experienced
with location testing to ensure the accuracy of results. Calibration testing was also
examined as it is important to the overall success or failure of this project.
Error testing was also examined, problems with dead zones that would not pick
up a transmitting tags location.




                                         47
7     Evaluation
This chapter explains testing that the location detection system underwent. It will
summarise the test result data from testing that was carried out on the system. It
will evaluate the accuracy of the ultra wideband location detection system in
being able to identify and accurately locate the position of transmitting tags. The
evaluation will look at how different materials may influence the accuracy of the
transmitting tags location. The evaluation tests how accurately the location
system can track the movement and location of a person wearing a tag from point
A to point B in a room.

This screen shot (Figure 46) shows the static location of the transmitting tag
indicated by the red dot. The black grid represents the actual area marked out in
one meter squares.




             0,0      0,1       0,2       0,3         0,4        0,5     X, axis




             Figure 46: Centre point of floor plan marked out to scale

The floor was mapped out in a one meter square grid. The green X indicates the
Centre of the actual floor. This corresponds to Grid reference 1.5 on the Y axis
and 2.5 on the X axis on (See Figure 48). A number of readings were taken


                                        48
around the area covered by the sensors. This was done methodically starting at
grid reference (0,0 Y, axis - 0,0 X, axis). Further readings were taken moving the
tag to different locations were the grid lines meet finishing at grid ref reference
(0,3Y, axis 0,5 X, axis). This ensured that all cross references were covered.

Figure 47 shows the grid area mapped in centimetres squared to allow for better
accuracy readings to be taken. This allowed for accurate measurements to be
taken and compared to the onscreen readings of the position of the transmitting
tag.




                      Figure 47: Plan to scale of area in cm




Figure 48: Sensors in operation locating transmitting tag id: 010-000-015-099

The readings from the location of the Transmitting tags can be seen in Appendix
E: Tag: 010-000-015-099 actual location was near the centre of the room grid
reference (0,1.5 Y, axis - 0,2. X, axis). The location of the tag from the sensors
placed it at grid reference (0,1.5 Y, axis - 0,1.8 X, axis). This shows a difference
on the X axis of approx (.2) of a meter difference. The Y axis reading from the
sensors is almost perfect.


                                        49
7.2                            Evaluation Results

Performance testing evaluates the success of the location detection system
claims compared with the actual results obtained through the testing of system
using different scenarios. Actual results as compared with manufactures claims.
Table 3 shows events that take place and the event attributes.
                                    Event Source                Event Class                          Event Attributes
       1                      Active Tag                  A Tag                        Tag type: either person or equipment
                                                                                       user id identifies the owner of the badge
       2                      Transmitting tag            Sensor equipment is          Tag identifier:
                                                          activated .                  x,y,z: coordinate system:
                                                                                       uniquely identifies the badge
                                                                                       a 3D coordinate relative to a coordinate
                                                                                       system
       3                      Tag moved                   Sensors pick up the          Scanning wave signals intersect to indicate
                                                          signal from the              the location of the tags new location.
                                                          transmitting tag

                               Table 3: Showing the event source, event class and event attributes


7.3                            Evaluation results of tag location test.

                                                      Location results for T ag id 101-111-015-099


                                                      Distance in meters X axis
                                     0.25    0.5   0.75     1     1.25   1.5    1.75    2    2.25   2.5   2.75    3
                               3
                             2.75
 Distance in meters Y axis




                              2.5
                             2.25
                               2
                             1.75
                              1.5
                             1.25
                               1
                             0.75
                              0.5
                             0.25
                               0

                                            Graph 1: Location results for Tag id 101-111-015-999

                             Yellow line represents the Y axis                         Green line represents the X axis

Graph 1 shows the results of a tag id 101-111-015-099 being paced at grid
reference .25cm on the Y axis and .25 cm on the X axis. The results are then
recorded and compared with the position where the sensors indicate that the tag
is. The yellow line indicates where the sensors have located the tag on the Y axis
and the green line indicates were the sensors have located the tag on the X axis.
The chart shows that the level of error is greater along the Y axis than along the X
axis. See Appendix B for screenshots of the location data.




                                                                                50
7.4           Evaluation results of water test.
The purpose of the following experiments is to see how a liquid, in this case water
can effect and influence the location accuracy readings of the ultra wideband
location detection systems

Liquid Experiment:

                                                                                                        Movement
                 Water Test                Predicted Result                 Actual Result               Difference

1         Transmitting tag id           Expected there to         The location software indicates      Discrepancies
          number 010-000-015-115        displacement of the       the location of the Tag id           From original
          placed at a central           tags location caused by   number 010-000-015-115 did              position.
          location in the room          the water interfering     move when it was placed under            Y axis
          under a basin filled to the   with the signals          the basin filled with water              6cm up
          top with water.                                         After two minutes only two of the         X axis
                                                                  sensors were picking up the               same
                                                                  tags location.


2         Transmitting tag id           Expected there to be      Scanning wave signals were           Discrepancies
          number 010-000-015-115        less displacement of      less visible at the point were the   From original
          placed at a central           the tags location         tag was located. On screen              position.
          location in the room          caused by the reduced     software indicated that the Tags         Y axis
          under a basin Half filled     water level interfering   location had moved                      4cm up
          to the top with water.        with the signal                                                    X axis
                                                                                                           same

3         Transmitting tag id           Expected there to be      All four sensors did locate the      Discrepancies
          number 010-000-015-115        little interference       Transmitting tag. Very slight        From original
          placed at a central           caused by the water       deviation from the tags original        position.
          location in the room                                    position                                 Y axis
          under a basin filled with 1                                                                      2cm up
          cm of water.                                                                                      X axis
                                                                                                            same

4         Transmitting tag placed       Expected there to be      All four sensors did locate the      Discrepancies
          beneath a basin with no       slight interference       Transmitting tag. No noticeable      From original
          water in it                   caused by the basin       interference caused to the              position.
                                                                  position of the tag                      None
                                                                                                           Y axis
                                                                                                           none
                                                                                                           X axis


          Transmitting tag id           All Sensors to pick up    All sensors did pick up the          Discrepancies
Control




          number 010-000-015-115        signals from              transmitting tags signals.           From original
          placed at a central           transmitting tag and be   Location of tag was easily              position.
          location in the room          able to locate the tag    identifiable with id number              none
                                        accurately                visible on screen
                               Table 4 Water test results (See Appendix A)

Conclusion: Results indicate that water does cause interference (See graph 1)
with the location accuracy reading of the ultra wideband location detection
system. The results show that the position of the tag which is being tracked does
show a positional change in the presence of water. These results raise the
question, if a person is wearing a transmitting tag how will their body which
contains 70% fluid interfere with the accuracy readings.




                                                           51
7.5              Evaluation results of material test.
The purpose of the following experiments is to see how different materials can
effect and influence the operational accuracy readings of the ultra wideband
location detection systems.

Material Experiment:

                                                                                                      Tag covered by
                  Material Test              Predicted Result                 Actual Result              material

1         Lead                         Expected there to be a high     Interference was caused to     High interference
                                       degree of interference in       the accurate location of tag      caused to
                                       accurately locating Tag id      id number 010-000-015-            accurately
                                       number 010-000-015-099          099 location.                  locating the tags
                                       location Because of the                                            position
                                       properties that make up
                                       lead.

2         Tin.                         Expected there to be            Interference was caused to     Mild interference
                                       interference in accurately      the accurate location of tag      caused to
                                       locating Tag id number 010-     id number 010-000-015-            accurately
                                       000-015-099 location            099 location. However not      locating the tags
                                                                       as much                             position
                                                                       As the lead experiment

3         Wood                         Expected there to be some       No Interference was             No interference
                                       interference in accurately      caused to the accurate            caused to
                                       locating Tag id number 010-     location of tag id number         accurately
                                       000-015-099 location            010-000-015-099 location       locating the tags
                                                                                                           position

4         Plastic                      Expected there to be some       No Interference was             No interference
                                       interference in accurately      caused to the accurate            caused to
                                       locating Tag id number 010-     location of tag id number         accurately
                                       000-015-099 location            010-000-015-099 location       locating the tags
                                                                                                           position

          Tag id number 010-000-       All Sensors to pick up          All sensors did pick up the     Discrepancies
          015-099 was placed on        signals from transmitting tag   transmitting tags signals.      From original
Control




          The table in the same        and be able to locate the tag   Location of tag was easily         position.
          position for all             accurately                      identifiable with id number         None
          experiments. No                                              visible on screen
          obstacles blocking line on
          sight from sensors
                              Table 5 Material test results (See Appendix B)

Conclusion: Material made lead and tin do cause interference to the accurate
location of transmitting tag id number 010-000-015-099. Materials made from
plastic or wood do not interfere with the capabilities of the ultra wideband location
detection system from accurately receiving the signals transmitted by the
transmitting tag id number 010-000-015-099. The four sensors were able to
accurately locate and pinpoint the location of the tag.




                                                          52
7.6     Evaluation results of other tests carried out
        Performance Test            Predicted Result                 Actual Result              Difference

1   Tag attached to an           Sensors to pick up        Sensors did pick up the                 Pass
    individual, who walked in    signals from              transmitting tags signals as the
    a straight line from point   transmitting tag and be   individual walked in a straight
    A to Point B                 able to locate and        line. Location software was
    (See appendix C)             update the individuals    updated and the individual’s
                                 movements as they         progress could be monitored.
                                 walk

2   Tag is moved to a            Sensor equipment is       Scanning wave signals intersect     Pass but with
    different position on the    activated and locates     to indicate the location of the         some
    floor                        the new position of the   tags new location                   discrepancies
    (See appendix D)             transmitting tag.

3   Transmitting tag placed      Other sensors should      Sensors did not locate the               Fail
    directly beneath sensors,    have picked up the        Transmitting tag
    at floor level               signal from the
                                 transmitting tag

4   Transmitting tag placed      Sensors should pick up    Sensors did have difficulty         Did locate tag
    beneath a basin of water     the tags signal and       picking up tags location.             with some
    Screenshot data and          location                  Introduction of water did have an   discrepancies
    Table 4 (See appendix E)                               effect on the results
    For more detailed results

5   Position Transmitting tag    Sensor location           The software indicates the          Passed for Y
    at centre point of all the   software from the four    location of the Tag by a red dot         axis
    sensors at floor level.      sensors scan the area     on screen overlaid onto grid        Error 2cm for
                                 to locate the             map of the area covered. Tag is         X axis
                                 transmitting tag          identified by its IP address
                                     Table 6 Other test results

Conclusion: Table 6 shows some other performance tests that were carried out
on the transmitting tags and how the sensors were able to accurately locate the
tags under different conditions. Performance test 1 (See appendix C) shows that
the location detection software was able to successfully track and locate a person
wearing a transmitting tag walking in a straight line from one location to another
location.
Test 2: A transmitting tag was moved to different locations within the room and
readings were taken (See appendix D). There were some discrepancies with the
location accuracy of the tags.
Test 3: Areas directly below the sensors do not pick up the location of the
transmitting tags with any degree of accuracy (see Figure 44). There appears to
be a correlation between the accuracy of locating the tags and their location
directly beneath the location sensors.
Test 4 Disturbance was caused to the accuracy of the tags location when it was
covered by water. The more water that covered the tag the greater the tags
location signal was deflected. (See appendix E).
Test 5 A transmitting tag was placed in the centre of the room which had been
accurately mapped out (see Figure 46) This allowed an accurate reading of the
tags location which could be compared to the location which the software showed
was the tags location onscreen. The location detection was able to successfully
pin point the tags location to 2 cm accuracy. This showed that in the centre of the


                                                    53
room the accuracy of the location detection system was more reliable here than in
other locations away from the centre
Graph 2: Initial disturbance caused to the transmitting signal when a full basin of
water is placed over the tag id number 010-000-015-115 (see graph 1). The
graph shows deflection caused to the transmitting tags signal from before the
water was introduced.


                                           A Column Graph to showing how a liquid can influence
                                                  the performance of a transmitting tag.
                                                      See Water Test 1 Appendix A.

                                       7
   Signal movement intefference (cm)




                                       6

                                       5

                                       4

                                       3

                                       2

                                       1

                                       0
                                            1     2     3     4      5        6      7   8   9    10
                                                                  Time ( Seconds )

Graph 3: Shows disturbance caused to a transmitting tags signal.




                                                                         54
                                             A Scatter Graph to showing how a liquid can influence
                                                     the performance of a transmitting tag.
                                                          See Water Test 1 Appendix A
                                     7
  Signal movenent inteference (cm)



                                     6       Basin full of
                                             water
                                     5       is placed
                                     4
                                             over tag

                                     3

                                     2
                                                                                                   As water
                                     1                                                          stabilises reading
                                                                                                remains constant
                                     0
                                         0     0.5      1        1.5     2      2.5     3     3.5        4   4.5     5
                                                             Transmitting signal readings in (Seconds)




Graph 4: Shows the position of the transmitting tag as it is moved further away
from the centre of the room. The reliability of the location detection system is
effected by how far the transmitting tags are from the central position covered by
the sensors.




                                                                                55
Graph 5: shows how the error rate becomes more acute the further the tag is
moved from the central position in the room.
                                                         A Column Graph to Showing the anomolies produced as a tag
                                                                moves away from centre of the scanned area.
                                                     5

                                            4.5
 Error Difference from centre (cm)




                                                     4

                                            3.5

                                                     3

                                            2.5
                                                     2

                                            1.5

                                                     1

                                            0.5

                                                     0
                                                                 1          2     3       4      5      6      7       8      9      10
                                                                     Error readings as tag is moved from centre of scanned area (cm)




Graph 6: Shows the readings taken from a person wearing a transmitting tag
walking from point A in the room to point B in a straight line. See Appendix C


                                                             A Scatter Graph Showing the relationship between area
                                                             covered by the location detection system and the actual
                                                                               location of the tags

                                                         3


                                                     2.5
                         Width of area covered (m)




                                                         2


                                                     1.5

                                                         1


                                                     0.5
                                                                                                  Tags mean Location from point a to point b
                                                         0
                                                             0         0.5     1      1.5     2       2.5      3      3.5     4      4.5       5
                                                                       Length of area covered (m) For Screenshots see Appendix C


Graph 7: Shows the error detection results see Appendix C for the screen shots




                                                                                                    56
                                 A Column Graph Showing the Movement of a
                            transmitting tag from point a to point b across the area
                                  scanned by the location detection system.
                       3


                      2.5
   Area covered (m)




                       2


                      1.5


                       1


                      0.5


                       0
                              1     2      3      4      5      6     7        8   9   10
                                               Readings taken see Appendix C




7.3 Conclusion
This chapter shows the evaluation results from tests that were carried out using
transmitting tags and the location detection sensors to located the tags and allow
readings of the results to be displayed in tabular and graphical form.
The results were summarised and conclusions made depending on the results of
the particular experiment.




                                                         57
8 Project conclusion
This research project is concerned with the testing of an accuracy of an indoor
location system utilising ultra wideband. The project explores the location
detection systems and the benefits that it can bring to the robotics industry. In
robotics there are many types of navigation devices these vary from wireless
systems to systems using vision. However one thing that they have in common is
that without these types of location systems, robots would find it difficult to
navigate autonomously. The key to robot navigation is Self localisation; this
allows a robot to navigate between two points. By using a combination of map
building and self localisation a robot will be able to successfully plan paths in
relation to its surroundings in the real world.
Determining the location of objects or people in a smart space is one of the
prerequisites enabling smart applications. Ultra wideband location detection
system has the advantages of being able to carry out precision localisation and
handle multi-path signals. Sensor networks based ultra wideband location
detection system provides greater accuracy than other systems.

Ultra wideband sonar location system is a new technology which aims to
overcome many of the problems that affect other types of indoor location
systems, especially in an industrial environment where interference from other
mechanical and electrical devices can have an adverse effect on location
detection devices. The potential for this system to deliver accurate indoor location
is substantial. The system may produce beneficial side-effects for the robotics
industry and other industries. The fundamental principles that govern this
interaction between robot, task and environment are, at the moment, only partially
understood.

This project has proposed Ultra-Wideband Location Positioning Navigation
System architecture suitable for the support of mobile robotics within a typical
indoor workplace environment. From my investigation and testing of the Ubisense
Ultra wideband location detection system I have found that the technology is
capable of locating transmitting tags while having the advantage of low power
consumption with fast data transfer rates over the network which I set up and
configured.

Ultra wideband location detection technology's unique characteristics make it a
suitable solution for use in the tracking of robots in an indoor environment,
offering acceptable positioning location although interference from obstacles in
the line-of-sight of the sensors is one of the major causes of error. Line-of-sight
obstacles degrade the accuracy of the time of arrival estimation of the direct path
signal by making the multipath structure complex as was experienced when more
than one tag was introduced to the area covered by the sensors.




                                        58
Chapter 1 outlined the aims and objectives of this project and a brief overview of
this project. Current approaches, and related research were reviewed in chapter
2, including research into various type of location detection systems GPS
systems, Wi-Fi (802.11) and robotics navigation systems. It explored the benefits
that this new technology may have for the robotics industry.
Chapter 3 examined the requirement specifications of a Location Positioning
Navigation System architecture. This chapter described the functional and non
functional requirements of the proposed system. Chapter 4 examined the design
and implementation of the location detection system. The architecture of system
setup was examined the hard wiring of the system. Configuration of the system
software and screen shots of the server software in operation was examined. An
abstract view of information produced by the sensors monitoring the environment
was given. Calibration of the sensors and rudimentary diagrams showing the
system in operation was detailed.

Integration of the location detection system including HCI issues were examined
in Chapter 5. Chapter 6 identified the testing of the location detection system; this
included testing of transmitting tags within the representation of a room boundary.
Estimations of transmitting tag location from results supplied by the sensors were
compared with the real location of the tags position. Chapter 7 described the
performance evaluation of the location detection system within the real world
environment and evaluates the performance of the system against manufacturer’s
claims.

This project has showed that it is possible to setup and configure a location
detection system that is capable of locating transmitting tags within a small
geographical area. Hodges and Louie (1994) describe an Interactive Office that
gathers information about the activity of the occupants of an office; this data is
generated by a number of different sensor types which monitor movement of
people.

The field of robotics can also benefit from this new technology in helping to
accurately detect the location of robots. However the accuracy of the transmitting
tags location detection can be influenced by many factors, reflection from other
surfaces, atmospheric conditions.

To summarise the evaluation of this Ultra-Wideband Location Positioning System
concludes that at present the reliability for its use over a large domain with high
numbers of transmitting tags may cause problems. When testing this system in a
small geographical area, the performance of the system to locate a single tags
position was not as accurate as claimed by the manufacturer. When multiple
transmitting tags were introduced into the area covered by the sensors, the
systems performance became more unreliable. This will influence the reliability
and suitability of this system in the robotics field.




                                         59
9 Potential Future Work
The area of location detection is becoming increasingly important. Knowledge of
the locations of people and equipment will have a profound impact on our daily
lives.
Location detection systems are already having a major impact e.g. GPS systems,
RFID tags etc. However current systems are ad- hoc in nature. In order for
location detection systems to be really effective will require a wider deployment
and a substantial user base is required. At present however this area is still
largely underdeveloped. There are many limitations to be overcome such as
network delays, how a distributed sensor system handles delivery of events from
multiple sensors and run time errors. Future work in this area will provide a more
realistic determination of its capabilities and will expose previously unconsidered
application areas.
 It is not impossible to visualise a system will be developed to incorporate all the
benefits of location detection systems which can handle thousands of objects
over very large domains and can provide inter-domain functionality and the
supply of multiple services.




                                        60
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                                        63
Appendix A
Test results on how a liquid can effect a tags location and detection.
Prior to the test taking place a grid was marked out in one centimeter squared
paper. Tag id number 010-000-015-115 was placed at the intersection of the grid
points and a reading was taken as a control to identify the position of the tag.




Tag id number 010-000-015-115 uncovered is placed in a location within the room,
no obstacles to prevent transmitting tag signals from reaching the sensors located
at a height of 2.5meters at the corners of the room.
Control:




Tags id number 010-000-015-115 identified by the small red dot on screen
indicating its location in relation to the area scanned by the wall mounted sensors.




                                         64
Test 1




Basin completely filled with water placed on top of the tag id number 010-000-015-
115. The tags position indicated by the red dot has slightly moved down and to the
right.
This could be caused by deflection with water now covering the tag. We can see
also that the tag is now only being seen by three of the sensors. Sensor
00:11:CE:71 is not locating the tag. The wave lines from the sensors are not as
strong only one showing.




After 1 minute three of the sensors pick up the position of the tag id number 010-
000-015-115 position. Tags id 010-000-015-115 location has moved by 6cm on the
y axis from its original position. This could be due to water disturbance.


                                        65
After leaving the Water covering the tag for 2 minute the new reading shows that
the tag id number 010-000-015-115 is now only being picked up by two sensors.
Tags id 010-000-015-115 location is 3cm on the y axis from its original position.
This is after the disturbance of the water has had time to settle.

Test 2: Basin half filled with water

Tags id number 010-000-015-115 location placed at a central position in the room.
Tag is being seen by four of the sensors and its position is identified by the red
dot. Location position of tag is at the same position as the control.




Basin half filled with water placed over tag id number 010-000-015-115


                                        66
We can see from the screen shot that the tags location has moved by 6cm
upwards on the Y axis. The tag is once again only being seen by three of the
sensors. Sensor 00:11:CE:71 is not locating the tag.




After leaving the tag id number 010-000-015-115 for
 2 minutes the tag is only seen by three of the sensors. The displacement location
of the tag has stabilised at 4cm upwards on the Y axis.

Test 3: Basin filled with 1 cm of water.




Basin filled to a depth of 1 cm with water placed over tag id number 010-000-015-
115. The screen shot shows that the tags location has moved up 2 cm from its
original location.


                                           67
Test 4: Plastic basin is placed over Tags id number 010-000-015-115 no change in
the location of the tag compared with the control.




                                       68
Appendix B
Test results on how different materials effect a tags location and detection.

The purpose of the following experiments is to see how different materials can
effect and influence the operational accuracy readings of the ultra wideband
location detection systems.

Lead Experiment:

Control




Screenshot showing the location of tag id number 010-000-015-099, Tag is
placed on a table on grid paper, no obstacles preventing line of sight
interference. Four sensors are each placed at a height of 2.5 meters in the
four corners of the room.
Sensor id numbers are 11:CE:00:0F:56 master sensor and slave sensors
00:11:CE:00:0E:, 00:11:CE:00:71and 00:11:CE:38




                                       69
Test 1




An object made of lead is placed in front of sensors sensor
00:11:CE:00:71and 00:11:CE:00:38 one can see that the location position of
the tag remains the same. There does appear to be interference caused the
sensor serial number 00:11:CE:00:71 and 00:11:CE:00:38. However master
sensor 11:CE:00:0F:56 and slave sensors 00:11:CE:00:0E: are able to
accurately locate the position of tag id number 010-000-
015-099.




                                   70
Test 2




A piece of lead is placed in front of master sensor 11:CE:00:0F:56 and slave
sensor 00:11:CE:00:0E:BF. The location of tag id number 010-000-015-
099.is not picked up. The location of the lead in front of master sensor
11:CE:00:0F:56 and slave sensor 00:11:CE:00:0E:BF has caused the
operation of the location detection to fail.




                                    71
Test 3




Lead is placed on top of the tag id number 010-000-015-099. From the
screenshot we can see that the tags location is not identified.


Conclusion: The lead experiment indicates that an object made of lead does
interfere with the ability of the sensors to accurately locate the transmitting tag
id number 010-000-015-099 location.




                                        72
Tin Experiment:

Control: No obstacles in line of sight of sensors




Screenshot showing the location of tag id number 010-000-015-099, Tag is
placed on a table on grid paper.

Test 1
An object made from tin is placed in front of sensors sensor
00:11:CE:00:71and 00:11:CE:38 one can see that the location position of the
tag remains the same.




                                       73
Test 2
An object made from tin is placed in front of sensors 11:CE:00:0F:56 and
sensor 00:11:CE:00:0E:BF. From the screenshot one can see that the
location position of the tag is not picked up.




Test 3




Initially the tag id number 010-000-015-099 was not seen by the sensors.



                                     74
After approx 5 sec the tag id number 010-000-015-099 was located the
sensors. However sensor serial number 00:11:CE:00:71did not activate.

Conclusion: The tin experiment indicates that an object made of tin does
cause some interfere with the ability of the sensors to accurately locate the
transmitting tag id number 010-000-015-099 location.


Wood experiment
Control: No obstacles in line of sight of sensors




Test 1
An object made from wood placed in front of tag id 010-000-015-099 in order
to block signals from sensor 00:11:CE:00:71and 00:11:CE:38




                                       75
The tags position is still accurately located with no perceivable interference
caused by the wood obstructing or interfering with the transmitting signals
from the tag.

Test 2
An object made from wood is placed in front of sensors 11:CE:00:0F:56 and
sensor 00:11:CE:00:0E:BF. From the screenshot one can see that the
location position of the tag remains the same.




                                     76
Test 3

Wood is then placed on top of the tag id number 010-000-015-099 to see if a
material made from wood will interfere with the detection signals from the
location sensors. The screenshot shows that there is no effect on the ability of
the sensors to accurately pick up the location signal from the tag id number
010-000-015-099.




Conclusion: The wood experiment indicates that an object made of wood
does not interfere with the ability of the sensors to accurately locate the
transmitting tag id number 010-000-015-099 location.




                                      77
Plastic Experiment:
Control: No obstacles in line of sight of sensors




Test 1
Plastic is placed in front of tag id number 010-000-015-099




An object made from plastic is placed in front of sensors sensor
00:11:CE:00:71and 00:11:CE:38 The location position of the tag remains the
same.




                                       78
Test 2




An object made from plastic is placed in front of sensors 11:CE:00:0F:56 and
sensor 00:11:CE:00:0E:BF. From the screenshot one can see that the
location position of the tag remains the same.

Test 3
Plastic is then placed on top of the tag id number 010-000-015-099 to see if a
material made from plastic will interfere with the detection signals from the
location sensors.
There has been no effect on the ability of the sensors to accurately pick up
the location signal from the tag id number 010-000-015-099.




                                     79
Conclusion: The plastic experiment indicates that an object made of plastic
does not interfere with the ability of the sensors to accurately locate the
transmitting tag id number 010-000-015-099 location.




                                    80
Appendix C
Results from tracking a person wearing a tag from point A to point B.

Test to track and time the movement of a person wearing a tag id number
010-000-015-115 moving in a straight line from location A to location B across
the area covered by the four sensors.

Test Data for walking in a straight line from location A to location B




   Reading 1




   Reading 2



                                        81
Reading 3




Reading 4




            82
Reading 5




Reading 6




            83
Reading 7




Reading 8




            84
   Reading 9




   Reading 10

Conclusion: Ten readings were taken at points along the path from location A
to location B. The resulting data show that the system was able to locate and
track the path of the person wearing the tag id number 010-000-015-115 as
they transverse the area covered by the four sensors




                                     85
Appendix D
Results of tests carried out on the accuracy readings of a tags location.
Location accuracy of Tag 010.000.015.099




  y




                                             X

Tag 010.000.015.099 located in a diagonal 25 cm from bottom right hand wall
(X) and 25 cm from opposite wall (Y).




  y




                                            X

Tag 010.000.015.099 located in a diagonal 50 cm from bottom right hand wall
(X) and 50 cm from opposite wall (Y).



                                       86
Tag 010.000.015.099 located in a diagonal 75 cm from bottom right hand wall
(X) and 75 cm from opposite wall (Y).




 y




                                         X


Tag 010.000.015.099 located in a diagonal 1 m from bottom right hand wall
(X) and 1 m from opposite wall (Y).




 y




                                             X




                                    87
Tag 010.000.015.099 located in a diagonal 1.25 m from bottom right hand
wall (X) and 1.25 m from opposite wall (Y).




  y




                                          X


Tag 010.000.015.099 located in a diagonal 1.5 m from bottom right hand wall
(X) and 1.5 m from opposite wall (Y).




 y




                                            X




                                     88
Tag 010.000.015.099 located in a diagonal 1.75 m from bottom right hand
wall (X) and 1.75 m from opposite wall (Y).




 y




                                      X

Tag 010.000.015.099 located in a diagonal 2 m from bottom right hand wall
(X) and 2 m from opposite wall (Y).




     y




                                          X

Tag 010.000.015.099 located in a diagonal 2.25 m from bottom right hand
wall (X) and 2.25 m from opposite wall (Y).



                                    89
Tag 010.000.015.099 located in a diagonal 2.5 m from bottom right hand wall
(X) and 2.5 m from opposite wall (Y).




 y




                                         X


Tag 010.000.015.099 located in a diagonal 2.75 m from bottom right hand
wall (X) and 2.75 m from opposite wall (Y).




  y




                                          X




                                    90
Tag 010.000.015.099 located in a diagonal 3 m from bottom right hand wall
(X) and 3 m from opposite wall (Y).




 y




                                          X



Tag 010.000.015.099 located in a diagonal 3.25 m from bottom right hand
wall (X) and 3.25 m from opposite wall (Y).




 y




                                          X




                                    91
Tag 010.000.015.099 located in a diagonal 3.5 m from bottom right hand wall
(X) and 3.5 m from opposite wall (Y).




  y




                                          X




                                     92
Appendix E
Test results: Liquid disturbance test
Liquid test: How does the Tag id 010.000.015.099 operate when covered by a
liquid i.e. (water).




Figure shows location of tag id 010.000.015.099 on table before being
covered by a basin of water.




                                     93
On placing the basin of water over the tag id 010.000.015.099, the location
indicated by the red dot appears to move backwards slightly.




On leaving the basin to settle the tag id 010.000.015.099 location has moved
almost back to its original position.




                                      94
Appendix F
Test Results: Three tags transmitting at the one time.


If three tags are brought into the area being scanned it causes confusion. The
sensors rapidly skip from one Tags location to the next one. Tag id
010.000.015.248
Tag id 010.000.015.199 and Tag id 010.000.015.115.




                       Tag id 010.000.015.248 location




                       Tag id 010.000.015.199 location



                                      95
Tag id 010.000.015.115. location




              96
Appendix G
Configuration and setup of the location detection system

                       Ubisense Location detection system.


                                                      Status LEDs

   Sensors




     Computer setup and how the location detection system is setup
                                                                     Transmitting tags




      Eight port Netgear Switch used to connect Sensors to computer.



                                       97
Appendix H
Problems with the setup and configuration of the location detection system


Third party Server software used to issue Dynamic IP addresses to the
Ubisense sensors in order for them to function properly. When using third
party software it is sometimes difficult to find support and documentation
when problems occur.

When initially running the Server software a conflict occurred with the IP
addresses not being recognised by Ubisense Location Engine. This problem
was identified by the Led codes from the sensors see figure: below.
The code combination pointed to a DHCP timeout.




      Figure: status codes indicated by LEDs on the Ubisense sensors




                                      98
Figure: Location Engine Configuration showing initial allocation of IP
addresses form 192.168.3.10-14 by the DHCP Server software. The status of
the IP Addresses is unknown.

Below confirmation of the DHCP timeout, use of the ping command verified
that there was a problem with the addresses issued by the DHCP Server.




   Figure: Failure of packets sent to Dynamic IP address 192.168.3.14
   allocated by the DHCP Server application.




                                    99
Appendix I

       PROJECT SCHEDULE
                                             January              February              March              April
       RESEARCH ACTIVITES               W1   W2 W3     W4   W1    W2 W3      W4   W1   W2 W3    W4   W1   W2 W3    W4
       INVESTIGATIVE/SELECTIVE
       Further location determination
       based research on systems
       Learn      configuration    of
       Ubisense      hardware    and
       software
       Learn the necessary software
       packages for algorithms
       Set        up       necessary
       experimental framework for
       evaluation.
       SYSTEM IMPLEMENTATION
       Create experiments

       Enhance prototype

       Evaluate results
       Compare system with Vicon
       camera based system
       Build in slack for unplanned
       problems
       INTEGRATION             AND
       TESTING
       WRITE UP OF THESIS




                                                                 100

				
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