COMPUTER-AIDED REAL-TIME KINEMATIC GLOBAL POSITIONING SYSTEM POSITIONING TECHNIQUE FOR DEFORMATION

MEASUREMENT AND ANALYSIS

LEE CHEH HANG

UNIVERSITI TEKNOLOGI MALAYSIA

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To my beloved family who unselfishly supported me throughout the entire endeavour

and those who inspired me. They make it all worthwhile.

iv

ACKNOWLEDGEMENT

There are many people I would like to recognise for their help and support

with my research. Without them, this thesis would never have been possible for me.

First and foremost, I would like to convey my special thanks to my supervisor

Prof. Dr. Halim Setan for accepting me as his student, particularly that he had three

other researches on hand at that moment. My sincere gratitude also goes to his

patient guidance and constructive suggestions throughout the entire research.

Next, I would like to thank my best friends who provided many idea and

support for this research. Thank you Mr. Kee, Madam Chong, Miss Teong, Miss Lee,

Mr. Shu, Mr. Voon, Mr. Sharuddin and Madam Suraya. I am deeply indebted to your

kindness and help.

Besides, I would like to acknowledge everyone who provided the technical

support for this research. Thanks to Mr. Abu Bakar (Faculty of Civil Engineering),

Mr. Soeb (Geodesy Section, Department of Survey and Mapping, Malaysia), Mr.

Nomy (Trimble Singapore), Mr. Lim (Global-trak System) and Mr. Bakri (Geodesy

Laboratory, Faculty of Geoinformation Science and Engineering) for their help and

kindness.

Lastly, I would like to express my deepest appreciation to my beloved family

who have always unselfishly given me the proper guidance, encouragement and

moral support throughout not only the research, but also my entire life. I love you all.

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ABSTRACT

Scientific justification and technical feasibility of using Real-Time Kinematic

Global Positioning System (RTK-GPS) positioning as the technique in recording the

responses (in term of coordinate / position) of deformable structures have been

proven very promising. The major advantages are the real-time measurement (either

online or offline) and direct measurement of relative displacement. Nevertheless, the

research, through the sampled data, shows the need of additional steps to handle the

possible errors in direct employment of manufacturers’ RTK positioning solution for

deformation monitoring. In addition, most of the further applications such as online,

automated, continuous, etc., however, have to be self customized and developed. The

sampled data comprise short baseline (1.8km, collected in Universiti Teknologi

Malaysia) and medium length baseline (27.7km, provided by Geodesy Section,

Department of Survey and Mapping, Malaysia). The research thus suggests an

additional approach for RTK positioning integrity monitoring and deformation

detection. The RTK positioning integrity monitoring includes error identification,

outlier filtering and reference station stability checking. The essence of the approach

is the Normal Point technique as well as the Local Threshold and Global Threshold.

Reference for Local Tolerance and Global Tolerance are also discussed. To get the

additional approach running more efficiently in one single system, prototype

software, Sparrow, was developed in Visual Basic environment and by deploying the

Trimble bundled software, which are Trimble GPS Configurator and Trimble

Reference Station. Sparrow is also developed to serve for online, automated, and

continuous deformation monitoring. At the same time, Sparrow provides real-time

and past result presentation in both graphical and numerical format. Three tests are

taken to verify the applicability of Sparrow and the validity of Normal Point.

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ABSTRAK

Kajian mengenai penggunaan Sistem Penentududukan Global Kinematik

Masa Hakiki (Real-Time Kinematic Global Positioning System, RTK-GPS) untuk

mencatat tindakbalas (dalam bentuk koordinat / kedudukan) struktur yang mengalami

deformasi telahpun banyak dibuktikan kemunasabahannya. Kelebihan utamanya

adalah pencerapan masa hakiki (sama ada secara online ataupun offline) dan

pencerapan pergerakan relatif secara langsung. Walau bagaimanapun, dengan data

sampel, kajian ini menunjukkan keperluan langkah tambahan untuk mengendali

selisih yang mungkin wujud dalam penyelesaian secara langsung penggunaan RTK

daripada pengilang (manufacturer) untuk pemantauan deformasi. Tambahan pula,

kebanyakan aplikasi lanjutan seperti online, automatik, berturutan (continuous), dan

sebagainya perlu dicorak dan dibangunkan sendiri. Data sampel itu merangkumi

garis dasar pendek (1.8km, dicerap di Universiti Teknologi Malaysia) dan garis dasar

sederhana panjang (27.7km, dibekalkan oleh Seksyen Geodesi, Jabatan Ukur dan

Pemetaan Malaysia). Oleh itu, kajian ini mencadangkan satu kaedah tambahan untuk

pemantauan integriti penentududukan RTK dan pengesanan deformasi. Pemantauan

integriti penentududukan RTK merangkumi pengenalpastian selisih, penurasan

selisih kasar, dan pemeriksaan kestabilan stesen rujukan. Kelebihan kaedah

tambahan tersebut adalah teknik Titik Normal dan Had Global serta Had Lokal.

Rujukan untuk Toleransi Global dan Toleransi Lokal juga dibincangkan. Untuk

mengendali kaedah tambahan itu dengan lebih efisien dalam satu sistem tunggal,

perisian prototaip, Sparrow, telah dibangunkan dalam environmen Visual Basic dan

mempergunakan perisian sediaada dalam Trimble iaitu Trimble GPS Configurator

dan Trimble Reference Station. Sparrow juga dibangunkan untuk pemantauan

deformasi yang bertujuan online, automatik, dan berturutan. Di samping itu, Sparrow

memberikan persembahan keputusan masa hakiki dan lepas dalam bentuk grafik dan

numerikal. Tiga ujian telah diambil untuk mengesahkan penggunaan Sparrow dan

Titik Normal.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

TITLE PAGE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF ABBREVIATIONS xv

LIST OF SYMBOLS xvii

LIST OF APPENDICES xix

1 INTRODUCTION

1.1 Background 1

1.2 Problem Statements 5

1.3 Research Objectives 7

1.4 Research Contributions 7

1.5 Research Methodology 8

1.6 Outline of the Thesis 9

2 DEVELOPMENT OF DEFORMATION

MONITORING AND EMPLOYMENT OF GLOBAL

POSITIONING SYSTEM

2.1 Introduction 11

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2.2 Global Development of Deformation Monitoring 12

2.3 Classification of Deformation Models and

Terminology 14

2.3.1 Conventional Deformation Analysis 15

2.3.2 Advanced Deformation Analysis 16

2.3.3 Parametric Models 20

2.4 Classification of Monitoring Schemes 22

2.4.1 Conventional Monitoring 22

2.4.2 Modern Monitoring 23

2.5 Scientific Justification and Technical Feasibility of

GPS Employment 24

2.5.1 Buildings 24

2.5.2 Bridges 25

2.5.3 Dams 26

2.5.4 Landslides 26

2.5.5 Integrated approach 27

2.6 Competency of RTK Positioning in Deformation

Monitoring 28

2.7 State-of-the-Art Deformation Monitoring System 31

2.7.1 GeoMoS 31

2.7.2 Condor Monitoring Systems 32

2.7.3 GRAZIA 32

2.7.4 GPSAD2000 33

3 GLOBAL POSITIONING SYSTEM AND REAL-TIME

RELATIVE KINEMATIC POSITIONING

3.1 Introduction 34

3.2 Basic Concept of Satellite Positioning 34

3.3 Satellite Range Measurements 37

3.4 GPS Signal Structure 39

3.5 GPS Ranging 40

3.5.1 Pseudo-range Measurement 40

3.5.2 Carrier Phase Measurement 43

3.6 GPS Positioning Mode 45

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3.7 Absolute Positioning 47

3.8 Relative Positioning 50

3.8.1 Code Pseudo-Range Tracking 50

3.8.2 Carrier Phase Tracking 52

3.9 Kinematic Positioning 53

3.10 Real-Time Relative Kinematic Positioning 55

3.10.1 Real-time Versus Postmission Processing 56

4 GLOBAL POSITIONING SYSTEM ACCURACIES

AND ERROR SOURCES

4.1 Introduction 58

4.2 GPS Accuracies 58

4.3 GPS Error and Bias Sources 61

4.3.1 Satellite and Receiver Clock Biases 62

4.3.2 Orbit Biases 64

4.3.3 Ionospheric Delay 65

4.3.4 Tropospheric Delay 66

4.3.5 Carrier Beat Phase Ambiguity 67

4.3.6 Cycle Slips 67

4.3.7 Multipath and Imaging 69

4.4 GPS Augmentation Options 71

5 REAL-TIME KINEMATIC POSITIONING

INTEGRITY MONITORING AND DEFORMATION

DETECTION

5.1 Introduction 73

5.2 Result of Sampled Data 74

5.2.1 Short Baseline Group 74

5.2.2 Medium Length Baseline Group 78

5.3 RTK Positioning Integrity Monitoring 79

5.3.1 Error Identification 80

5.3.2 Outlier Filtering 84

5.3.3 Reference Station Stability Checking 87

5.4 Deformation Detection 89

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5.5 Reference for Local and Global Threshold 92

6 PROTOTYPE SOFTWARE: SPARROW

6.1 Introduction 95

6.2 Software Briefing 95

6.3 Software Design 97

6.3.1 Data Collection 97

6.3.2 Data Processing 98

6.3.3 Data Transfer 99

6.3.4 Result Presentation 100

6.3.5 Data Archiving 101

6.4 Software Structure 101

6.4.1 System Segment 102

6.4.2 Field Segment 105

6.5 Software Functionalities 108

6.5.1 Online, Automated and Continuous

Monitoring System 108

6.5.2 Refined RTK Positioning Solution 108

6.5.3 Versatile Result Presentation 109

6.5.4 Flexible and Scaleable Monitoring System 110

6.6 Result of Sparrow Field Test 111

7 CONCLUSION AND RECOMMENDATIONS

7.1 Introduction 115

7.2 Conclusion 115

7.3 Recommendations 117

7.3.1 Enhancements on Data Processing and

Algorithm, and Hardware 117

7.3.2 Enhancements on Software Functionality

and Stability 118

REFERENCES 120

APPENDICES A – F 126 - 174

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LIST OF TABLES

TABLE NO. TITLE PAGE

1.1 Example of damage 3

2.1 Summary of global development of deformation monitoring 14

2.2 Geodetic modelling of deformation processes in space and

time 15

2.3 Characterization and classification of deformation models 20

4.1 GPS biases and errors 62

5.1 Particulars of the observations (short baseline) 74

5.2 Particulars of the observation (medium length baseline) 78

5.3 Two parts of data extracted from original dataset 83

5.4 Statistical summary of first epoch observation 92

5.5 Statistical summary of second epoch observation 93

6.1 Total of failed data 114

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LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 Main focus of the research scope 5

1.2 Research methodology 8

2.1 Deformation as an element of a dynamic system 16

2.2 Hierarchy of models in geodetic deformation analysis 18

2.3 Method of system identification 20

2.4 Advancement of monitoring scheme 24

3.1 The basic concept of satellite point positioning system 35

3.2 Intersection of three ranges with radii 36

3.3 The basic concept of relative satellite positioning 37

3.4 Pseudo-range measurement 41

3.5 Carrier beat phase measurement 45

3.6 “Family tree” of GPS positioning 47

3.7 Concept of pseudo-ranging 48

3.8 Absolute kinematic positioning 54

3.9 Relative kinematic positioning 54

4.1 Satellite distributions of good and poor GDOPs 59

4.2 Cycle slips 68

4.3 Direct signal and multipath signal 70

5.1 Reference station at UTM observatory (left) and rover

station at UTM hockey field (right) 75

5.2 (a) Time series of northing of first epoch (March 16, 2006) 75

5.2 (b) Time series of easting of first epoch (March 16, 2006) 76

5.2 (c) Time series of elevation of first epoch (March 16, 2006) 76

5.3 (a) Time series of northing of second epoch (April 11, 2006) 77

5.3 (b) Time series of easting of second epoch (April 11, 2006) 77

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5.3 (c) Time series of elevation of second epoch (April 11, 2006) 78

5.4 Reference station BANT (Banting) at Sek. Men. Keb. Sg.

Manggis (left); Rover station UPMS (UPM Serdang) at Jab.

Kej. Biologi & Pertanian (right) 79

5.5 (a) Time series of elevation, MyRTKNet, 13:59:47 – 19:59:46,

August 6, 2006 80

5.5 (b) Time series of elevation, MyRTKNet, 19:59:47, August 6,

2006 – 01:59:46, August 7, 2006 81

5.6 Time series of elevation, MyRTKNet, 01:59:47 – 07:59:46,

August 8, 2006 81

5.7 (a) Time series of northing, MyRTKNet, 01:59:47 – 07:59:46,

August 7, 2006 82

5.7 (b) Time series of northing variation, MyRTKNet, 01:59:47 –

07:59:46, August 7, 2006 83

5.8 (a) Time series of northing normal point of first epoch

observation 86

5.8 (b) Time series of easting normal point of first epoch

observation 86

5.8 (c) Time series of elevation normal point of first epoch

observation 87

5.9 Reference station is disturbed 88

5.10 Sample layout of field component distribution 89

5.11 (a) Time series of northing (integrated) 90

5.11 (b) Time series of easting (integrated) 91

5.11 (c) Time series of elevation (integrated) 91

6.1 Fundamental of Sparrow 96

6.2 Structure of Sparrow 101

6.3 Workflow of Conveyor 103

6.4 Screenshot of main window of Conveyor 104

6.5 Screenshot of main window of Compiler 105

6.6 Sample layout of the components at the field 107

6.7 Real-time result presentation in graph form 109

6.8 Example of the distribution of field components in the larger

area 110

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6.9 (a) Results of first test – N 111

6.9 (b) Results of first test – E 112

6.10 (a) Results of second test – N 112

6.10 (b) Results of second test – E 113

6.11 (a) Results of third test – N 113

6.11 (b) Results of third test – E 114

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LIST OF ABBREVIATIONS

ASNT American Society for Nondestructive Testing

C/A-code Coarse/Acquisition Code

CC Control Centre

CRS Core Reference Station

CSP Control Station Processing

CW Continuous Wave

DoD United States Department of Defence

DOP Dilution of Precision

FBG Fiber Bragg Grating

FDD Frequency Domain Decomposition

FEM Finite Element Method / Modelling

FFT Fast Fourier Transformation

FIG International Federation of Surveyors

GGA GPS fix information

GPS Global Positioning System

GT Global Threshold

LAN Local Area Network

LSE Least Squares Estimation

NP Normal Point

InSAR Interferometric Synthetic Aperture Radar

IWST Iterative Similarity Weighted Transformation

JUPEM Department of Survey and Mapping, Malaysia

LT Local Threshold

LGT Lower Global Threshold

LLT Lower Local Threshold

MIMO Multiple Input - Multiple Output

MINT Malaysian Institute for Nuclear Technology Research

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NAVSTAR Navigation Satellite Time and Ranging

NDT Non-Destructive Testing

NMEA National Marine Electronics Association 0183 Standard

NP Normal Point

OP Original Point

OTF On-the-Fly

P-code Precision code

PRN Pseudo-Random Noise

PRC Pseudo-Range Correction

RF Radio Frequency

RRS Reserved Reference Station

RTK Real-Time Kinematic

SHM Structural Health Monitoring

SPS Standard Position Service

TCP/IP Transmission Control Protocol / Internet Protocol

TGO Trimble Geomatics Office

TPS Terrestrial Positioning System

TRS Trimble Reference Station

TSIP Trimble Standard Interface Protocol

UERE User Equivalent Range Error

UHF Ultra High Frequency

UGT Upper Global Threshold

ULT Upper Local Threshold

UM Usage Monitoring

UTC Universal Time Coordinated

USACE United State Army Corps of Engineers

VBA Visual Basic for Applications

VHF Very High Frequency

VNC Virtual Network Computing

WG 6.1 Working Group 6.1 on Deformation Measurements and Analysis

WGS84 World Geodetic System 1984

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LIST OF SYMBOLS

no - Fundamental natural frequency or period of a building

D - Base direction (in meters) in the direction of motion considered of the

building

H - Height of the building (in meters)

C - Centre of mass of the earth

R - Position vector of the antenna to seek

r - Known position vector of satellite

ρ - True range from transmission at satellite to reception at receiver or

antenna

y - Propagation of electromagnetic wave from the satellite to the receiver

A - Signal amplitude

k - Propagation wavenumber related to the free space wavelength

t - Elapsed time measured from the instant of transmission at the satellite

x - Distance travelled of the electronic wave from the satellite to the

receiver

ω - Radian frequency

φ - Bias term

fo - Fundamental frequency of GPS signal

p - Measured pseudo-range

c - Velocity of light

dt - Offset of the satellite clock from GPS time

dT - Offset of the receiver clock from GPS time

dion - Ionospheric delay

dtrop - Tropospheric delay

Φ - Measured carrier phase in length units

N - Unknown cycle count

xviii

λ - Wavelength

σo - Measurement accuracy

σ - Positioning accuracy

RE - Range error due to clock instability / timing biases

TO - Time offset

DC - Dry term range contribution in zenith direction in meters

PO - Surface pressure in millibar (mb)

TL - Local tolerance

TG - Global tolerance

N - Meridian arc distance from reference station (of user-defined

coordinate system used in Sparrow)

E - Arc distance along the parallel latitude from reference station (of user-

defined coordinate system used in Sparrow)

h - Ellipsoidal height of antenna (of user-defined coordinate system used

in Sparrow)

φ - Latitude of geodetic coordinate system

λ - Longitude of geodetic coordinate system

H - Antenna altitude of geodetic coordinate system

Ngeoid - Geoidal separation

Sφ - Meridian arc distance

Sλ - Arc distance along the parallel latitude

RM - Radius of curvature in meridian

RN - Radius of curvature in the prime vertical

xix

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Street, Drainage and Building Act 1974 (Act 133) 126

B Enhancements of Data Processing, Algorithms or Software 129

C Time Series of Sampled Forty-Eight-Hour Continuous

MyRTKNet Data 135

D National Marine Electronics Association 0183 Standard 147

E Coordinate Conversion 149

F Field Procedure and Testing of Sparrow 153

CHAPTER 1

INTRODUCTION

1.1 Background

Numerous accidents or disasters associated with large construction projects

and natural events in the past have cost not only the great loss financially but also the

lives that eternally embedded the great pain in the memory of their beloved family

and friends. These horrendous tragedies include

(i) Sultan Abdul Halim Ferry Terminal Bridge collapse (July 31, 1988),

(ii) Highland Towers Condominium collapse (December 11, 1993),

(iii) Tsunami induced by the Indian Ocean earthquake (December 24,

2004), and

(iv) many other landslides, tremors as well as sudden collapse of the floor

of a building during construction.

Further information on the abovementioned tragedies can be acquired at Wikipedia,

(the free encyclopedia) and the study, entitled Non-Destructive Testing of Concrete

and Civil engineering Structures, carried out by Malaysian Institute for Nuclear

Technology Research (MINT). Besides, questions on whether our buildings are able

to withstand the tremors have also been raised by the recent aftershocks caused by

the earthquakes that struck the region. Further information on the discussion of the

aftershocks can be reached at Property Times, the New Straits Times (2006).

These tragedies and aftershocks have awakened the public awareness and

concern of the structure safety as well as natural event. Also, the need of monitoring

has been called to serve as the alarm system or early-warning system. According to

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aforementioned study carried out by MINT, it was reported that amendment had been

made to Street, Drainage and Building Act 1974 (Act 133) as a follow up of the

Highland Towers tragedy. The act requires that after every ten years all high-rise

building of more than five floors must be inspected for their safety before the

renewal of certificate of fitness can be made. The Section 85A of the act is attached in

Appendix A.

In usual practices, the non-destructive testing (NDT) or structural health

monitoring (SHM) will be implemented to assess the damage in structure and

examine the integrity of the structure in order to come to a conclusion of the useful

life or serviceability of the structure. In general, NDT and SHM hold a same role

which is to ultimately guarantee the safety of the public. A brief introduction on

NDT as well as SHM and damage is given in the following.

The American Society for Nondestructive Testing (ASNT) define the NDT as

comprising those test methods used to examine an object, material or system without

impairing its future usefulness. The term is generally applied to nonmedical

investigations of material integrity. Non-destructive testing is concerned in a

practical way with the performance of the test piece, such as, how long may the piece

be used and when does it need to be checked again. The British Institute of Non-

Destructive Testing define the NDT as the branch of engineering concerned with all

methods of detecting and evaluating flaws in materials of that the flaws can affect the

serviceability of the material and structure.

Based on A Review of Structural Health Monitoring Literature: 1996-2001,

SHM is defined as the process of implementing a damage detection strategy for

aerospace, civil, and mechanical engineering infrastructure. Usage monitoring (UM)

attempts to measure the inputs to and responses of a structure before damage so that

regression analysis can be used to predict the onset of damage and deterioration in

structural condition (further discussion on the inputs to and responses of structure is

continued in Section 2.3.2. Prognosis is the coupling of information from SHM, UM,

current environmental and operational conditions, previous component and system

level testing, and numerical modelling to estimate the remaining useful life of the

system (Sohn et al., 2003). Also, according to Summary Report on the first

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International Workshop on Structural Health Monitoring, the essence of SHM

technology is to develop autonomous built-in systems for the continuous real-time

monitoring, inspection, and damage detection of structures with minimum labour

involvement (Harb, 2005).

In the most general terms, damage can be defined as changes introduced into

a system that adversely affects its current or future performance. Implicit in this

definition is the concept that damage is not meaningful without a comparison

between two different states of the system, one of which is assumed to represent the

initial, and often undamaged, state. On the study of damage identification in

structural and mechanical systems, the definition of damage therefore will be limited

to changes to the material and / or geometric properties of these systems, including

changes to the boundary conditions and system connectivity, which adversely affect

the current or future performance of these systems (Sohn et al., 2003). Some of the

examples of damage are shown in the Table 1.1 below.

Table 1.1: Example of damage.

Damage Change

Crack Stiffness change

Scour Boundary condition change

Weight loss Mass change

Joint loosening Connectivity change

However, to have the comprehensive diagnosis of the structure health or

prognosis of damage in detail, there are a number of different measurements that

have to be made for instance (but are not limited to) strain, acceleration, temperature,

transmission and displacement. Further classification on the measurement is

discussed in Section 2.3.2 (Ad-Hoc Committee of FIG, 2001; Sohn et al., 2003).

Nevertheless, the displacement measurement is the main concern of this thesis.

Basically, the displacement could be arrived at by two main approaches,

namely geotechnical approach and geodetic approach. Geotechnical approach uses

the special devices such as strain gauges, piezometers, tiltmeters, extensometers and

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many others to obtain the required type of displacements. However, the geodetic

approach uses the surveying positioning techniques to derive the displacement.

Either geotechnical or geodetic approach, they can be employed to measure / monitor

the displacement of the man-made structure (e.g. dam, high-rise building, bridge,

tunnel, etc.) and natural features (e.g. slope and the areas encountering with landslide,

subsidence, liquefaction, uneven settlement, mass movement, etc.).

The thesis focuses on the geodetic approach. The main difference of the

geodetic approach is that it uses the surveying technique to provide the feedback of

the response of the monitored object in term of position, which is, in turn, used to

derive the displacement (magnitude and direction) as well as displacement speed

(velocity). The derived displacement can be then described as deflection, settlement,

drift and others. For this reason, displacement measurement is also comparable to

deformation measurement.

Besides, in geodetic approach, there is also a number of positioning

techniques that can be used to perform the displacement measurement, such as

conventional terrestrial based method (by using theodolite or total station), global

positioning system (GPS) and photogrametry (by using camera or scanner). However,

GPS is the positioning technique to be looked into in this research.

Moreover, regardless to the positioning mode (absolute positioning or relative

positioning), GPS positioning technique can be further divided into two different

technique, namely, static positioning and kinematic positioning. Yet, the research

focuses on the kinematic positioning with real-time solution or in short real-time

kinematic (RTK) positioning technique.

Summing up all the comments abovementioned, in short, the main focus of

the research scope is shown in the “reserve pyramid” in Figure 1.1.

5

Non-Destructive Testing / Structural Health Monitoring

Displacement / deformation measurement

Geodetic approach

GPS positioning

RTK positioning technique

Figure 1.1: Main focus of the research scope.

Before continuing the discussion, some statements on the terms used in the

thesis are advisable. Throughout the thesis, displacement and deformation are

comparable. However, deformation measurement and deformation monitoring are

not quite comparable. Deformation measurement is used to represent the quantitative

measurement, whereas, deformation monitoring is used to represent the practice in

the real scenario, inclusive of both deformation measurement and analysis.

1.2 Problem Statements

Back in the late of 1970s, the GPS technology was introduced when the first

launch of the GPS satellite on February 22, 1978 (Leick, 2004). Since then, many

industries have been benefited from the technology of GPS. Surveying industry has

been no different. Researches have been (and are still) carried out and benefits have

been (and are still) brought in. However, due to the expensive equipments (as

compared to the conventional terrestrial surveying equipments), GPS technology is

still fresh in Malaysian surveying industry. Only the education institutions and

government departments have the regular practices. Furthermore, Malaysia, the

country that has been gifted the advantageous geographical and geological location

(e.g. free from earthquake and volcano), have no intensive practices in monitoring

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(structures as well as natural events). This also results the lack of proper reference or

standard guideline for using GPS in deformation monitoring. Nevertheless, as it has

been discussed in Section 1.1, there are, in truth, the needs of deformation

monitoring in Malaysia.

Today RTK positioning technique is certainly one of the most valuable assets

of GPS. Although many researches have suggest and proven the feasibility of using

RTK positioning (examples are given in Section 2.5) in deformation monitoring,

directly employing the manufacturers’ RTK positioning solution (the output obtained

from the receiver) in deformation monitoring is doubtful. In other words, the possible

errors (e.g. multipath and cycle slips) and reference station reliability that deteriorate

the quality of RTK positioning are the main concern.

Besides, the main essence of RTK positioning is its advantage to provide the

direct measurement of relative displacement and real-time measurement (online and

offline application). Nevertheless, until latest, there is still very lack off-the-shelf

online RTK positioning application, while offline RTK positioning solution does not

offer the real time (on the spot) deformation monitoring. Real time deformation

detection plays the prominent role in guaranteeing public safety.

Furthermore, automated and continuous monitoring is also the latest and in

demand monitoring. This is because automated and continuous monitoring greatly

levels the efficiency of deformation monitoring, such as, saving the manpower,

reducing human gross error and handling the round-the-clock monitoring. However,

the smart and handy applications have to be self developed or customized.

A reliable RTK positioning technique for deformation monitoring and a

computer-aided approach to perform the online, automated and continuous

deformation monitoring are the concern of the thesis.

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1.3 Research Objectives

Based on the problem statements discussed in the previous section, the

research objectives are as follows.

(i) To investigate RTK positioning integrity monitoring and deformation

detection method to improve the direct employment of manufacturer’s

RTK positioning technique for deformation monitoring system.

(ii) To enhance the employment of RTK positioning technique in

deformation monitoring, particularly in online, automated and

continuous deformation monitoring by developing prototype software.

1.4 Research Contributions

Parallel to the research objectives, the research has two significances as

follows.

(i) An additional method for RTK positioning integrity monitoring

(inclusive of RTK output quality and reference station stability) and

deformation detection is proposed.

(ii) A prototype deformation monitoring system for automated, online and

continuous monitoring scheme is developed. The prototype can be

reference for structure deformation and landslide study that concerns

the public safety in Malaysia.

The main difference between the research and other glorious and famous

researches is that the research looks into an additional method for manufacturers’

RTK positioning solution which concerns the RTK integrity monitoring and

deformation detection so that it can be employed directly for online, automated and

continuous deformation monitoring. Algorithm development for processing raw GPS

data to obtain the RTK solution for deformation monitoring is not in the scope of the

research, yet, it is recommended for future work.

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1.5 Research Methodology

The process of the whole research is summarised as shown in the flow chart

in Figure 1.2.

Figure 1.2: Research methodology.

Literature review:

To look for the appropriate scope of research that is relevant and significant to local needs.

Data sampling and analysis:

To collect sample data so as to i) look into the aptitude of RTK positioning, ii) to propose the proper method for deformation

monitoring (inclusive of RTK data monitoring), and

iii) verify the appropriateness of using the RTK positioning technique in deformation monitoring.

Prototype software development:

To develop prototype software based on the findings of the research and to serve the purposes of automated, online and continuous deformation monitoring.

Simulation test:

To justify the findings of the research and test the technical feasibility of the developed prototype software.

Start

Conclusion and recommendations:

To conclude the research and to give the recommendations to the future works.

End

9

1.6 Outline of the Thesis

The thesis consists of seven chapters and six appendixes.

Chapter 1 gives the introduction to the research by delivering the background

Chapter 2 peruses the development of deformation monitoring (global

Chapter 3 discusses the fundamental of GPS positioning as well as RTK

Chapter 4 discusses the GPS accuracies, error and bias sources, and

gmen

Chapter 5 presents the results of sampled data, and proposes an additional

ethod

Chapter 6 describes the developed prototype software, Sparrow. The

of the research, problem statements, research objectives, research contributions,

research methodology as well as structure of the thesis.

development of deformation monitoring, classification of deformation models and

terminology, and classification of monitoring schemes) and the employment of GPS

in deformation monitoring (scientific justification and technical feasibility,

competency of RTK positioning in deformation monitoring, and state-of-the-art

deformation monitoring system).

positioning technique. The chapter begins the discussion from the basic of satellite

positioning until the scope of RTK positioning, that include GPS signal structure,

GPS ranging, and GPS positioning mode, absolute positioning, relative positioning,

and kinematic positioning.

au tation options so that they can be referenced in the following chapters.

m for RTK positioning integrity monitoring (error identification, outlier

filtering and reference station stability checking) and deformation detection.

description includes the Sparrow briefing, software design, software structure and

software functionalities. Besides, three tests to verify the applicability of Sparrow

and validity of Normal Point (NP) are included.

10

Chapter 7 gives the concluding remarks of the research as well as the

Appendix A attaches the Section 85A from the Street, Drainage and Building

Appendix B attaches four examples of enhancements of data processing,

Appendix C presents the results of sampled forty-eight-hour continuous

Appendix D elucidates the National Marine Electronics Association (NMEA)

Appendix E discusses the conversion from geodetic coordinate system to the

Appendix F describes the field procedure of using Sparrow as well as process

recommendations to the future works.

Act 1974 (Act 133).

algorithms or software.

RTKNet data.

0183 Standard.

user-defined coordinate system used in the research.

and result of the tests for the developed prototype software.