MINISTRY OF EDUCATION AND TRAINING
HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY
NGUYEN DINH THUAN
ROBUST SIGNAL PROCESSING TECHNIQUES FOR MODERN
GNSS RECEIVERS
Major: Computer Engineering
Code No.: 9480106
COMPUTER ENGINEERING DISSERTATION
SUPERVISORS:
1. Assoc. Prof. Ta Hai Tung
2. Prof. Letizia Lo Presti
Hanoi - 2019
1
STATEMENT OF ORIGINALITY AND AUTHENTICITY
I confirm that my dissertation is an original and authentic piece of work written by
myself. The data, results in the thesis is reliable and has never been published by
others. I further confirm that I have fully referenced and acknowledged all material
incorporated as secondary resources in accordance with the regulations
Hanoi,
SUPERVISORS
PHD STUDENT
PGS.TS. Tạ Hải Tùng
Nguyễn Đình Thuận
Prof. Letizia Lo Presti
2
ACKNOWLEDGEMENTS
I would like to express my gratitude to Hanoi University of Technology, Graduate
School, School of Information and Communication Technology, Department of
Computer Engineering and Politecnico di Torino, NavSaS group for creating
favorable conditions for me to work and study.
I would like to express my special thanks to my supervisors, Assoc. Ta Hai Tung and
Prof. Letizia Lo Presti. The supervisors have always been helpful, giving great advice,
scientific orientations so that I can develop and complete my research.
Sincerely thank the lecturers, colleagues in the Department of Computer Engineering,
School of Information and Communication Technology, Hanoi University of Science
and Technology where I work, study and carry out research projects for the
enthusiastic in helping and encouraging me during the research.
With gratitude to teachers, scientists, colleagues and close friends for encouraging
and supporting me in the research process.
Finally, I would like to express my deep gratitude to my family for encouraging me
to overcome all obstacles to complete this thesis.
Nguyen Dinh Thuan
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TABLE OF CONTENTS
STATEMENT OF ORIGINALITY AND AUTHENTICITY ......................................... 1
ACKNOWLEDGEMENTS ................................................................................................ 2
TABLE OF CONTENTS .................................................................................................... 3
LIST OF ACRONYMS ....................................................................................................... 6
LIST OF TABLES ............................................................................................................... 8
LIST OF FIGURES ............................................................................................................. 9
INTRODUCTION ............................................................................................................. 13
1. FUNDAMENTAL BACKGROUND ....................................................................... 18
1.1. GNSS positioning principle .................................................................................. 18
1.2. History and development of GNSS ...................................................................... 19
1.3. GNSS Threats ....................................................................................................... 20
1.3.1. Multipath ....................................................................................................... 21
1.3.2. Atmosphere .................................................................................................... 21
1.3.3. Interference .................................................................................................... 21
1.3.4. Spoofing ........................................................................................................ 21
1.3.5. GNSS Segment errors .................................................................................... 21
1.3.6. Cyber Attacks ................................................................................................ 22
1.4. GNSS Receiver Architecture ................................................................................ 22
1.4.1. Signal Conditioning and Sampling ................................................................ 22
1.4.2. Acquisition .................................................................................................... 23
1.4.3. Tracking and Data Demodulation ................................................................. 23
1.4.4. Positioning Computation ............................................................................... 24
1.5. Countermeasures to GNSS Threats ...................................................................... 25
1.5.1. Antenna array processing techniques ............................................................ 25
1.5.2. Frontend and Digital Signal Conditioning based techniques ........................ 28
1.5.3. Correlator/Tracking and PVT based techniques ............................................ 29
1.6. GNSS Simulator and effect of sampling frequency .............................................. 30
2. GNSS SIGNAL SIMULATOR DESIGN AND IMPLEMENTATION ............... 32
2.1. Modeling methodology ......................................................................................... 32
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2.2. Overview of the modeling of antenna array signals in GNSS receivers .............. 32
2.2.1. General model of the received signal in GNSS receivers ............................. 33
2.2.2. Interference .................................................................................................... 37
2.2.3. Multipath ....................................................................................................... 38
2.2.4. Noise .............................................................................................................. 39
2.3. Effect of sampling frequency on the positioning performance ............................. 39
2.3.1. Residual code phase estimation ..................................................................... 40
2.3.2. Correlation output calculation ....................................................................... 40
2.3.3. Effect of sampling frequency on correlation shape and DLL discriminator
function 42
2.3.4. Effect of the sampling frequency and the integration period selection ......... 42
2.3.5. Effect on the presence of Doppler and local oscillator (LO) clock drift. ...... 45
2.3.6. Theoretical code tracking loop error estimate ............................................... 46
2.3.7. Theoretical results evaluation by simulated, and numerical models ............. 49
2.3.8. Effect of Doppler and coherent integration period ........................................ 50
2.4. Sampling Frequency Effect Mitigation Technique ............................................... 53
2.4.1. Receiver implementation ............................................................................... 55
2.5. Performance verification ....................................................................................... 57
2.5.1. Verification of the simulated antenna array signals ...................................... 58
2.5.2. Antenna distortion simulation ....................................................................... 64
2.5.3. Verification of multipath simulation ............................................................. 66
2.6. Conclusion ............................................................................................................ 67
3. ANTENNA ARRAY PROCESSINGS FOR GNSS RECEIVERS ....................... 69
3.1. The proposed solution for synchronizing separated antenna array element ......... 69
3.1.1. Determining the samples difference .............................................................. 70
3.1.2. Determining the clock phase shift ................................................................. 71
3.2. Implementation a low-cost antenna array ............................................................. 75
3.3. Antenna array frontend verification ...................................................................... 76
3.3.1. Phase difference between frontends .............................................................. 76
3.3.2. Carrier to noise ration improvement .............................................................. 77
