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Implementation of Passive Radar in a Processing Restrictive Environment

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Implementation of Passive Radar in a Processing Restrictive Environment IMPLEMENTATION OF A LOW-COST PASSIVE BISTATIC RADAR by Joshua Leigh Sendall Submitted in partial fulfilment of the requirements for the degree Master of Engineering (Electronic Engineering) in the Department of Electrical, Electronic and Computer Engineering Faculty of Engineering, Built Environment and Information Technology UNIVERSITY OF PRETORIA September 2016 © University of Pretoria SUMMARY IMPLEMNTATION OF A LOW-COST PASSIVE BISTATIC RADAR by Joshua Leigh Sendall Supervisor: Prof. W.P. du Plessis Department: Electrical, Electronic and Computer Engineering University: University of Pretoria Degree: Master of Engineering (Electronic Engineering) Keywords: Radar, passive radar, low-cost, adaptive filtering, clutter cancellation, direct-path interference cancellation, matched filtering, tracking filter, broadcast radio Passive radar detects and ranges targets by receiving signals which are reflected off targets. Communication transmissions are generally used, however, theoretically any signal with a suitable ambiguity function may be used. The exploitation of an existing transmitter and the removal of emissions allow passive radars to act as a complementary sensor which is useful in environments where conventional active radar is not well suited. Such environments are in covert operations and in situations where a low cost or spectrally efficient solution is required. Most developed passive radars employ intensive signal processing and use application specific equipment to achieve detection. The high-end processors and receiver equipment, however, detract from some of the inherent advantages in the passive radar architecture. These include the lower cost and power requirements achieved by removing transmitter hardware. This study investigates the challenges faced when removing application-specific and high end components from the system and replacing them with low-cost alternatives. Solutions to these challenges are presented and validated by designing and evaluating a radar using these principles. © University of Pretoria It was found that the major limitation in passive radar is the dynamic range of the receiver. While processing the signals was, and is, a significant challenge, be implemented on a low- cost, low-power embedded processor. This was achieved by asserting a few limitations to the configuration, exploiting the subsequently generated redundancy, and taking advantage of the parallelism by using general purpose graphics processing.. Even on this processor, the system was able to run in real time and able to detect targets up to 91 km (bistatic range of 195 km) from the radar. Department of Electrical, Electronic and Computer Engineering iii University of Pretoria © University of Pretoria OPSOMMING IMPLEMENTERING VAN 'N LAEKOSTE- PASSIEWE BISTATIESE RADAR deur Joshua Leigh Sendall Studieleier: Prof. W.P. du Plessis Departement: Elektriese, Elektroniese en Rekenaaringenieurswese Universiteit: Universiteit van Pretoria Graad: Magister in Ingenieurswese (Elektroniese Ingenieurswese) Sleutelwoorde: Radar, passiewe radar, laekoste, aanpasbare filter, sluierkansellasie, direkte baan-versteuringskansellasie, aangepaste filter, volgfilter, uitsendingsradio Passiewe radar spoor teikens op en meet die afstand na hulle toe deur seine te ontvang wat van die teikens af gereflekteer word. Uitgesaaide kommunikasieseine word meestal gebruik, maar teoreties kan enige sein met ʼn geskikte dubbelsinnigheidsfunksie gebruik word. In ʼn passiewe radar word senderhardeware en beheerde versendings nie benodig nie en daarom kan dit as ʼn aanvullende sensor gebruik word in omgewings waar konvensionele aktiewe radar nie geskik is nie. Voorbeelde van sodanige omgewings is koverte operasies en situasies waar ʼn goedkoper oplossing of effektiewer spektrumgebruik verlang word. Meeste bestaande passiewe radars maak gebruik van intensiewe seinverwerking en benut toegewyde hardeware om opsporing moontlik te maak. Die gebruik van gesofistikeerde prosesseerders en ontvangstoerusting doen egter afbreuk aan die inherente voordele wat passiewe radars sou kon inhou, byvoorbeeld die laer koste en laer kragvereistes wat verkry word deur sendinghardeware te verwyder. In hierdie studie is die uitdagings ondersoek wat vorendag kom wanneer toegewyde hardeware van die stelsel verwyder word en vervang word deur alternatiewe, laekoste-komponente. Oplossings vir hierdie uitdagings is gevolglik voorgestel en getoets Department of Electrical, Electronic and Computer Engineering iv University of Pretoria © University of Pretoria deur ʼn radar wat van hierdie beginsel gebruik maak, te ontwerp en te evalueer. Die resultate van die praktiese radartoetse dui daarop dat die voorgestelde oplossings wel werkbaar is. Daar is in hierdie studie bevind dat die grootse beperking van passiewe radar die dinamiese reikwydte van die ontvanger is. Seinprosessering was ʼn groot uitdaging en het ʼn paar beperkinge op die konfigurasie geplaas. Daar was egter steeds ʼn mate van prosesseringsoortolligheid wat benut kon word en parallelle prosesseringstegnieke is gebruik om die stelsel op ʼn laekoste- en laekrag- ingebedde prosesseerder te implementeer. Sodoende was dit moontlik om ʼn eenvoudiger prosesseerder suksesvol te implementeer. Die prosesseerder het die stelsel in staat gestel om intyds te werk en om teikens tot en met 91 km (193 km bistaties afstand) van die ontvanger af op te spoor. Department of Electrical, Electronic and Computer Engineering v University of Pretoria © University of Pretoria ACKNOWLEGEMENTS I would like to thank the following persons for their support. My supervisor, Warren Paul du Plessis: for the guidance, support and inspiration during my studies. Also for reading and correcting all of my reports and papers, and teaching me so much. Francois Maasdorp, Craig Tong, Christo Cloete, Rossouw van der Merwe and the CSIR: for supporting my research and “showing me the ropes”. My loving girlfriend, Melissa Reed: for being a foundation in my life. My parents: for their love and support, which is always there unconditionally. My Lord and saviour Christ Jesus: whom is my strength and shield, and through whom all thing are possible. Department of Electrical, Electronic and Computer Engineering vi University of Pretoria © University of Pretoria LIST OF ABBREVIATIONS ADC Analogue to Digital Converter ADS-B Automated Dependent Surveillance Broadcast AGC Automatic Gain Control ALU Arithmetic-logic Unit ARD Amplitude-Range-Doppler ATC Air Traffic Control AWGN Additive White Gaussian Noise BLAS Basic Linear Algebra Subroutines CFAR Constant False Alarm Rate CGLS Conjugate Gradient Least Squares CISC Complex Instruction Set Computing CPI Coherent Processing Interval CPR Compact Position Report CPU Central Processing Unit CUT Cell Under Test CW Continuous Wave DFT Discrete Fourier Transform DMA Direct Memory Access DPI Direct Path Interference EM Electromagnetic FAR False Alarm Rate FDC Frequency-domain Correlation FDTC Frequency-domain Time Correlation FFT Fast Fourier Transform FIR Finite Impulse Response FLOP Floating Point Operation FM Frequency Modulation GAL Gradient Adaptive Lattice Department of Electrical, Electronic and Computer Engineering vii University of Pretoria © University of Pretoria GPGPU General Purpose Graphics Processing Unit GPU Graphics Processing Unit LNA Low-noise Amplifier LPF Low-pass Filter LSB Least Significant Bit MAC Multiply-Accumulate MIMD Multiple Instruction Multiple Data MIMO Multiple Input Multiple Output MKL Math Kernel Library NaN Not a Number NLMS Normalized Least Mean Squared OEM Original Equipment Manufacturer OTS Off-the-Shelf PC Personal Computer PFA Probability of False Alarm PLL Phase-locked Loop PPS Pulse per Second RAM Random Access Memory RCS Radar Cross-section RF Radio Frequency RISC Reduced Instruction Set Computing RMS Root Mean Square RMSE Root Mean Square Error SDR Software Defined Radio SFDR Spurious Free Dynamic Range SIMD Single Instruction Multiple Data SIMT Single Instruction Multiple Thread SISD Single Instruction Single Data SLL Sidelobe Level Department of Electrical, Electronic and Computer Engineering viii University of Pretoria © University of Pretoria SM Streaming Multiprocessor SNR Signal to Noise Ratio TDR Target to Direct-path Ratio TDTC Time-domain Time Correlation Department of Electrical, Electronic and Computer Engineering ix University of Pretoria © University of Pretoria TABLE OF CONTENTS CHAPTER 1 INTRODUCTION ........................................................................................ 1 1.1 PROBLEM STATEMENT ...................................................................................... 1 1.1.1 Context of the problem .................................................................................. 1 1.1.2 Research gap .................................................................................................. 2 1.2 RESEARCH OBJECTIVE AND QUESTIONS ...................................................... 3 1.3 SCOPE ..................................................................................................................... 4 1.4 RESEARCH CONTRIBUTION .............................................................................. 7 1.5 OVERVIEW OF STUDY ........................................................................................ 7 1.5.1 Chapter 2 Passive Radar ................................................................................ 7 1.5.2 Chapter 3 Signal Acquisition ......................................................................... 7 1.5.3 Chapter
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