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ESTIMATING TIME PARAMETERS FOR RADAR PULSE DESCRIPTOR
WORDS USING FPGA
HATEM NABIH JABAS
UNIVERSITI TEKNOLOGI MALAYSIA
ESTIMATING TIME PARAMETERS FOR RADAR PULSE DESCRIPTOR
WORDS USING FPGA
HATEM NABIH JABAS
A project report submitted in partial fulfilment of the
requirements for the award of degree of
Master of Engineering (Electronics and Telecommunication)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
JUNE 2018
iii
DEDICATION
To my lovely mother, who gave me endless love, trust, constant
encouragement over the years, and for her prayers.
To my family, for their patience, support, love, and for enduring the ups and
downs during the completion of this thesis.
To my cousin, for his special support, trust, engorgement to accomplish this
work and standing beside me in every step.
This work is dedicated to them.
iv
ACKNOWLEDGEMENT
I wish to express my deepest appreciation to all those who helped me, in one
way or another, to complete this project. First and foremost, I thank Allah almighty
who provided me with strength, direction and purpose throughout the project. Special
thanks to my project supervisor Associate Professor Dr. Ahmad Zuri bin Sha’ameri
for his patience, guidance and support during the execution of this project and Dr.
Zulfakar Aspar for his great support and engorgement as well. Through their expert
guidance, I was able to overcome all the obstacles that I encountered in these enduring
ten months of my project. In fact, they always gave me immense hope every time I
consulted with him over problems relating to my project. May Allah reward them
abundantly.
Lastly, I would like to communicate my appreciation to my fellow graduate
students and contemporaries, who have supported me in various traditions may Allah
reward them.
v
ABSTRACT
Electronic warfare (EW) system is an important capability that can advance
desired military or, conversely, impede undesired ones. In a military application, EW
provides the means to counter, in all battle phases, hostile actions that involve the
electromagnetic (EM) spectrum. An electronic support (ES) system is used by the
military for intelligence gathering, threat detection, and as a support to electronic
attack system. Its main feature is to determine the Pulse Descriptor Words (PDWs)
which consists of: 1. Frequency. 2. Time of Arrival (TOA). 3. Pulse Width (PW). 4.
Direction of Arrival (DOA). Then, PDW signal will be applied on deinterleaver to
determine Pulse Repetition Interval (PRI) and it could be a simple pulse, staggered or
jittered pulse. The estimated signal parameters are then used as input to a classifier
network to determine the identity of the received signal. This project investigates on
the hardware implementation on FPGA (Field Programmable Gate Array) of the time
parameters of radar signals after the signal is demodulated. A set of test signals
representing different types of radar is first generated which is then used to estimate
pulse word descriptors from the time parameters. Using histogram analysis, the
estimated pulse word descriptors is then classified with a set of known data base. The
performance is evaluated at various signal-to-noise ratio conditions. In this work, 128
clock cycles are used to complete the signal analysing with various values of latency
depending on the PRP type. The design is more efficient in term of FPGA resources
utilization comparing with previous work. The proposed design can be used for the
purpose of auto-measure of time parameters in many EW applications which have
physical limitations in size, weight and power consumption (SWaP) such as in an
aircraft.
vi
ABSTRAK
Sistem Peperangan Elektronik (EW) adalah sebuah sistem keupayaan penting
yang boleh memajukan tentera yang dikehendaki atau sebaliknya menghalang orang
yang tidak diingini. Dalam aplikasi ketenteraan, peperangan elektronik menyediakan
cara untuk menghalang semua fasa pertempuran, aksi permusuhan yang melibatkan
spektrum elektromagnetik (EM). Sistem sokongan elektronik (ES) digunakan oleh
tentera untuk mengumpul maklumat perisikan, mengesan ancaman dan sebagai
sokongan kepada sistem serangan elektronik. Ciri utamanya adalah untuk menentukan
Pulse Descriptor Words (PDWs) yang terdiri daripada: 1. Kekerapan. 2. Masa ketibaan
(TOA). 3. Lebar denyutan (PW). 4. Arah kedatangan (DOA). Kemudian, signal PDW
akan diaplikasikan ke atas deinterleaver untuk menentukan Pulse Repetition Interval
(PRI) dan ia juga boleh menjadi nadi mudah atau nadi denyutan. Isyarat parameter
yang dianggarkan kemudiannya digunakan sebagai input kepada rangkaian pengelas
untuk menentukan identiti isyarat yang diterima. Projek ini menyiasat pelaksanaan
perkakasan ke atas isyarat radar iaitu masa parameter FPGA (Field Programmable
Gate Array) selepas isyarat demodulasi. Satu set ujian isyarat yang mewakili pelbagai
jenis radar dijana untuk pertama kali yang kemudiannya digunakan untuk
menganggarkan deskriptor kata denyut daripada parameter masa. Dengan
menggunakan analisis histogram, anggaran deskriptor kata denyut kemudiannya
diklasifikasikan dengan satu set pangkalan data yang diketahui. Prestasi ini dinilai
dengan pelbagai keadaan nisbah bunyi-ke-bunyi. Dalam projek ini, 128 kitaran jam
digunakan untuk melengkapkan analisis isyarat dengan pelbagai nilai latensi
bergantung kepada jenis PRP. Reka bentuk ini lebih cekap dari segi penggunaan
sumber FPGA berbanding kerja sebelumnya. Reka bentuk yang dicadangkan boleh
digunakan untuk tujuan pengukuran auto parameter masa dalam kebanyakan aplikasi
EW yang mempunyai batasan fizikal dari segi saiz, berat dan penggunaan kuasa
(SWAP) seperti dalam pesawat.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF ABBREVIATIONS xiii
1 INTRODUCTION 1
1.1 Background 1
1.1.1 Definition of Electronic Warfare (EW) 1
1.1.2 ES Receiving System 2
1.2 Problem Statement 3
1.3 Objective 4
1.4 Scope of Work 4
1.5 Research Flow 5
1.6 Summary 6
2 LITERATURE REVIEW 7
2.1 Basic Radar Principle 7
2.2 Radar Warning Receiver 8
2.3 Radar Signal Parameters 11
2.3.1 Frequency Parameters of Radar 11
2.3.2 Timing Parameters of Radar 12
viii
2.3.3 Types of PRI 13
2.4 PRI Estimation Techniques 14
2.5 Real-Time Implementation 15
2.6 Real-Time Processing Technologies 17
2.6.1 Microprocessors 17
2.6.2 General-Purpose Graphical Processing Units (GPUs) 17
2.6.3 Field Programmable Gate Arrays (FPGA) 18
2.7 Summary 18
3 THEORY 19
3.1 Introduction 19
3.2 Algorithm Flow Chart 19
3.2.1 Receive Noisy Signal and Denoising the Signal 21
3.2.1.1 Thresholding 21
3.2.1.2 Neyman-Pearson Theorem 22
3.2.2 PRP Extracting 23
3.2.3 PRP Analysing 24
3.2.4 Emitter Recognition 26
3.3 Data Flow Graph 27
3.3.1 Denoising and PRP Extracting 27
3.3.2 PRP Analysing 28
3.3.3 Extracting PRP Values from the RAM 30
3.3.4 PRP Type Recognition 32
3.4 Summary 32
4 RESULTS AND DISCUSSIONS 33
4.1 Overview 33
4.2 Matlab Simulation 33
4.2.1 Simple PRP 33
4.2.2 2-level Staggered PRP 34
4.2.3 Jitter PRP 35
4.3 Implementation on FPGA Results 36
4.3.1 Top-level Hardware Module 36
ix
4.3.1.1 Thresholding and PRP Extract module 37
4.3.1.2 PRP Analyse Module 37
4.3.1.3 Emitter Recognition Module 38
4.3.2 Compilation Report 38
4.3.3 Hardware Simulation Results 39
4.3.3.1 Simple PRP 39
4.3.3.2 2-level staggered PRP 40
4.3.3.3 Jitter PRP 41
4.4 System Efficiency 42
4.5 Summary 43
5 CONCLUSION AND RECOMMENDATIONS 44
5.1 Conclusion 44
5.2 Recommendations 44
REFERENCES 45
x
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Specifications of BOW radar warning developed by Saab
Avitronics 9
2.2 Typical pulse width τ 13
2.3 Typical PRI type 14
2.4 Synthesis report 16
4.1 Resources utilization of the design 39
4.2 Efficiency of the designed system 43
xi
LIST OF FIGURES
FIGURE NO. TITLE PAGE
1.1 EW subsystems 2
1.2 Block diagram of an ES receiving system 3
1.3 Project Flow Chart 5
2.1 Basic radar principle 7
2.2 Block diagram of typical RWR 9
2.3 Radar Warning Equipment 10
2.4 Waves and frequency ranges used by radar 11
2.5 A typical radar time line 13
2.6 (a)Simple, (b)Jitter, (c)2_level staggered, (d)3_level
staggered 14
3.1 PRP Estimation Algorithm 20
3.2 ES receiver block diagram. 21
3.3 Probability density functions of AWGN and the signal 22
3.4 PRP extracting block diagram 24
3.5 PRP analysing block diagram 25
3.6 Pattern recognition of the emitter 26
3.7 Thresholding and PRP extracting 28
3.8 PRP analyse 29
3.9 Extracting PRP values from the RAM 31
3.10 PRP type classifier 32
4.1 Simple PRP 34
4.2 2-level staggered PRP 35
4.3 Jitter PRP 36
4.4 Top-level module 36
xii
4.5 Functional block diagram(fbd) of thresholding and PRP
extract module 37
4.6 Functional block diagram (fbd) of PRP analyse module 38
4.7 System output of simple PRP 40
4.8 System output of 2-level staggered PRP 41
4.9 System output of jitter PRP 42
xiii
LIST OF ABBREVIATIONS
ARM - Antiradiation Missile
ART - Adaptive Resonance Theory
AWGN - Additive White Gaussian Noise
COMSEC - Conflict Removal and Communications security
DEW - Direct Energy Weapon
DOA - Direction of Arrival
EA - Electronic Attack
ECM - Electronic Countermeasure
ECCM - Electronic Counter-Countermeasure
ELINT - Electronic Intelligence
EMP - Electromagnetic Pulse
EMCON - Electromagnetic Emissions Control
EMS - Electromagnetic Spectrum
EP - Electronic Protection
ES - Electronic Support
EW - Electronic Warfare
FBD - Functional Block Diagram
FPGA - Field Programmable Gate Arrays
HDL - Hardware Description Language
IP - Instantaneous Power
NEMP - Nuclear Pulse
PRI - Pulse Repetition Interval
PRT - Pulse Repetition Time
PRF - Pulse Repetition Frequency
PRP - Pulse Repetition Period
PDW - Pulse Descriptor Word
RTL - Register Transfer Level
CHAPTER 1
INTRODUCTION
1.1 Background
Electronic warfare system uses focused energy, usually radio waves or laser
light, to confuse or disable an enemy's electronics. It can also involve listening
collecting an enemy's radio signals or sensing the emitters.
1.1.1 Definition of Electronic Warfare (EW)
The official military terminology describes electronic warfare (EW) shown in
Figure 1.1 as a military action aims to control the electromagnetic spectrum (EMS).
This purpose is accomplished through offensive electronic attack (EA), defensive
electronic protection (EP), intelligence gathering and threat recognition electronic
warfare support (ES) actions. These current definitions give each function a broader
scope with respect to terminology used previously, which was, respectively, electronic
countermeasures (ECM), electronic counter-countermeasures (ECCM), and electronic
warfare support measures (ESM). Another definition for EA function, in addition to
the last ECM function, the use of direct energy weapons (DEWs), antiradiation
missiles (ARM), and electromagnetic and nuclear pulses (EMP and NEMP) to destroy
enemy electronic equipment. The new EP function definition includes, in addition to
the previous ECCM function, the use of electromagnetic emissions control (EMCON),
the electromagnetic hardening of electronic equipment, EW frequency conflict
removal, and communications security (COMSEC) actions. The new ES function
definition is not very different from the previous ESM definition as both include near-
2
real-time threat recognition in support of immediate decisions relevant to EA, EP,
weapon avoidance, and targeting actions [1].
Figure 1.1: EW subsystems [2]
1.1.2 ES Receiving System
Modern radars can usually extract much more information from the target than
just the range. They can extract angle, radial velocity, pointwise or distributed
extension, aspect changes, jet engine vs. propeller modulation, and so forth. However,
the measurement of range (i.e., the distance to a target) is still the most important radar
function. The basic radar principle is shown in Figure 1.2.
3
Figure 1.2: Block diagram of an ES receiving system [3]
1.2 Problem Statement
• Estimating an accurate pulse repetition interval (PRI) in noisy
environment leads to missing pulses.
• The slower PRI analyzing leads to slower ES system response.
• Many of electronic support (ES) system applications have physical
limitations in size, weight and power consumption (SWaP) such as in
an aircraft.
4
1.3 Objective
• The PRI Estimation Algorithm is used to determine the PRIs of the
received pulse train.
• To increase the system response speed, the received signal is analysed
using FPGA.
• To increase the respond speed, the PRI estimation system is
implemented on the FPGA.
1.4 Scope of Work
• MATLAB mathematical software is used to carry out all the simulation
of algorithms.
• The noise in signal is assumed to be additive white Gaussian noise
(AWGN).
• Threshold is chosen using Neyman-Pearson theorem.
• Radar PRI types used in this work are simple, 2-level staggered, 3-
level staggered and jitter pulses.
• The received signal data is down sampled by 150, thus makes the PRI
shorter to be used in the design and simulation.
• Quartus II software is used to design and implement algorithm on
FPGA.
5
• ModelSim is used to simulate the Verilog code.
• Algorithm verified based on data captured at DSP Lab UTM.
1.5 Research Flow
Figure 1.3 shows the flow of tasks will be performed in this project. Existing
algorithm for PRI estimation will be adjusted and tested for different PRI types in
Matlab. Then algorithm will be converted to RTL and adjusted. Later, Verilog code
will be written using Verilog HDL. Finally, algorithm will implement on FPGA in
order to test it.
Figure 1.3: Project Flow Chart
Start
Literature review
Troubleshooting
Simulation using
ModelSim
Writing Verilog
code
RTL algorithm
adjustment
Converting
algorithm into RTL
Analyse algorithm
in MATLAB
End
Is the result
verified?
No
Yes
6
1.6 Summary
This chapter discussed the introduction of this project, shadowed by brief
explanation on electronic warfare and electronic support system. Problems were
stated, objectives and scope of this project were presented.
45
REFERENCES
[1] S.-K. Lin, "Introduction to Modern EW Systems. Edited by Andrea De
Martino, Artech House, 2012; 417 pages. ISBN 978-1-60807-207-1," Sensors
(Basel, Switzerland), vol. 13, no. 1, pp. 1146-1150.
[2] A. E. Spezio, "Electronic warfare systems," IEEE Transactions on Microwave
Theory and Techniques, vol. 50, no. 3, pp. 633-644, 2002.
[3] A. W. Ata'a and S. N. Abdullah, "Deinterleaving of radar signals and PRF
identification algorithms," IET Radar, Sonar and Navigation, vol. 1, no. 5, pp.
340-347, 2007.
[4] S.-K. Lin, “Evolution of Signal Emitters and Sensors,” in introduction to
Modern EW Systems, vol. 13, no. 1, Basel, Switzerland: Sensors, 2013, ch. 2,
sec. 2.3, pp. 1146-1150.
[5] D. Adamy, Introduction to electronic warfare modeling and simulation. Artech
House, 2003.
[6] https://saab.com/globalassets/commercial/air/electronic-warfare/radar-
warning-receivers/bow/bow-product-sheet.pdf
[7] http://www.radartutorial.eu
[8] C. Wolff, Radar Tutorial (Book1): Radar Basics. Western Pommerania:
Achatweg3, 2009.
[9] D. Adamy, EW 101: A first course in electronic warfare. Artech house, 2001.
[10] K. A. Ghani, K. Dimyati, and A. Z. Sha'ameri, “Review of Pulse Repetition
Interval Analysis based on Time of Arrival,”International Defense & Security
Technology Conference, pp. 24-27, 2014.
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Achatweg3, 2009.
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repetition interval (PRI) agility of an incoming radar emitter signal using
instantaneous power analysis," pp. 1-4: IEEE.
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Lopez-Vallejo, "Real-time radar pulse parameter extractor," pp. 0371-0375:
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[16] R .Murali Prasd and J .Pandu, "FPGA Implementation of High Speed Radar
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IEEE Micro, vol. 31, no. 6, pp. 58-63, 2011.
46
[18] Altera. (2011, May). Using Floating-Point FPGAs for DSP in Radar. Altera
Corporation. U.S.A. [Online]. Retrieved on November 15, 2017, from
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[19] J. Ender "Introduction to Radar Part 1" Scriptum of a lecture at the Ruhr-
Universtität Bochum 2011.