Analysis of Artifacts Inherent to Real-Time Radar Target Emulation Audrey L. Seybert

145 Pages·2016·9.42 MB·English

Analysis of Artifacts Inherent to Real-Time Radar Target
Emulation
By
Audrey L. Seybert
SubmittedtotheDepartmentofElectricalEngineeringandComputerScienceandthe
GraduateFacultyoftheUniversityofKansas
inpartialfulfillmentoftherequirementsforthedegreeof
MastersofScienceinElectricalEngineering
Dr. ChristopherAllen,Chairperson
Committeemembers
Dr. ShannonBlunt
Dr. JamesStiles
Datedefended: May9,2016
TheThesisCommitteeforAudreyL.Seybertcertifies
thatthisistheapprovedversionofthefollowingthesis:
AnalysisofArtifactsInherenttoReal-TimeRadarTargetEmulation
Dr. ChristopherAllen,Chairperson
Dateapproved: May9,2016
ii
Abstract
Executing high-fidelity tests of radar hardware requires real-time fixed-latency target
emulation. Because fundamental radar measurements occur in the time domain, real-
timefixedlatencytargetemulationisessentialtoproducinganaccuraterepresentation
ofaradarenvironment. Radartestequipmentisfurtherconstrainedbytheapplication-
specific minimum delay to a target of interest, a parameter that limits the maximum
latency through the target emulator algorithm. These time constraints on radar target
emulation result in imperfect DSP algorithms that generate spectral artifacts. Knowl-
edgeofthebehaviorandpredictabilityofthesespectralartifactsisthekeytoidentify-
ing whether a particular suite of hardware is sufficient to execute tests for a particular
radar design. This work presents an analysis of the design considerations required for
development of a digital radar target emulator. Further considerations include how
the spectral artifacts inherent to the algorithms change with respect to the radar en-
vironment and an analysis of how effectively various DSP algorithms can be used to
produce an accurate representation of simple target scenarios. This work presents a
modelrepresentativeofnaturaltargetmotion,amodelthatisrepresentativeoftheside
effectsofdigitaltargetemulation,andfinallyatrueHDLsimulationofatarget.
The Department of Energy’s National Security Campus is operated and managed by
Honeywell Federal Manufacturing & Technologies, LLC under contract number DE-
NA0002839.
iii
Acknowledgements
First, I would like to thank the Department of Energy, the NNSA, and Honeywell
FM&T for prioritizing and funding this research. I’ve enjoyed this experience im-
mensely and found it to be fruitful. Now, I have a lot of people to thank, and in my
opinion, that is a good problem to have. Dr. Chris Allen, I appreciate your guidance
during this process. I don’t know where I would be without your biweekly doses of
optimism and level headedness. You’ve taught me a lot and it has been a pleasure.
Dr. Shannon Blunt, thank you for challenging me by your example. Doug Chritton
and Kelly Gibson, you guys have been the eye of the storm. I would have been swept
away without the mental reprieve you offered. Sean, Kevin, Thad, Joe, Rich, Brooke,
thanks for pushing my career in this direction. It’s hard to articulate what it means to
have good mentors, but the biggest compliment I can think of is that I hope that one
day someone looks up to me the way I look up to you. Kelly Rodriguez, thanks for
all of the little things. You are an inspiration and a reminder to never take no for an
answer. I might have given up in the first week if it wasn’t for you, girl. Lu, Eric,
Patrick, Cenk, Lane, John, Brandon, and Jon, I appreciate you and I’m impressed by
your work. Thanks for the great discussions and opening my eyes to problems and
perspectives I could never have fathomed on my own. Also, I enjoyed going on the
roof. Mom and Dad, thanks for raising me to be curious and critical and capable of
realizingmydreams. Theworldistrulymyoyster,andIhaveyoutothank. Dad,your
phrase, “sometimes you have to do things you don’t want to do” lit the internal fire of
motivation that has kept me going this whole time. Mom, thank you for fostering my
creativityandteachingmethatwhenadoorcloses,Ishouldlookforawindow.
iv
Contents
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 OrganizationofThesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 RadarSignalModel 5
2.1 EnvironmentModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 RadarModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.1 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.2 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.3 BasicReceiverProcessing . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.4 BasicRadarMeasurements . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.5 MathematicalRepresentation . . . . . . . . . . . . . . . . . . . . . . . . . 21
3 TestArchitectureModels 26
3.1 DelayLineArchitectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1.1 CoaxialDelayLines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1.2 OpticalDelayLines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.2 DigitalMemoryArchitectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.2.1 Memory-OnlyArchitecture . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.2.2 MemoryandSingleSidebandDopplerArchitecture . . . . . . . . . . . . . 40
3.2.3 FineDelayControlArchitecture . . . . . . . . . . . . . . . . . . . . . . . 42
v
4 SignalQualityArtifacts 43
4.1 ArchitectureIndependentErrorSources . . . . . . . . . . . . . . . . . . . . . . . 43
4.1.1 AnalogReceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.1.2 Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.1.3 Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.1.4 AnalogTransmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.2 DigitalKernelEffects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.2.1 MemoryDelayElements . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.2.2 DigitalFilters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.2.3 DirectDigitalSynthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.3 DeviceEquationswithNon-idealEffectsIncluded . . . . . . . . . . . . . . . . . . 56
5 DetailedDesignandAnalysis 58
5.1 HardwarePlatform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.2 RadarSignalLevelDefinition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.3 HypotheticalRFFrontEnd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.4 TargetGeneratorAlgorithmDescription . . . . . . . . . . . . . . . . . . . . . . . 64
5.4.1 TopLevel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.4.2 DelayControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.4.3 DopplerControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
5.4.4 HDLDesignSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.5 TargetGeneratorDesignSummary . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6 SimulationDevelopmentandResults 74
6.1 SimulatedRadarParameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.2 SimulatedTargetDescription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
6.3 BaselineCase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.3.1 StaticTarget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
vi
6.3.2 MovingTarget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.4 VariationsontheTargetBaseline . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.4.1 Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6.4.2 MultipleTargets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.5 VariationsontheRadarBaseline . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.5.1 PRFandNumberofPulsesandCPI . . . . . . . . . . . . . . . . . . . . . 90
6.5.2 Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.5.3 WindowedResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.5.4 BPSK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.6 VariationsontheTargetGeneratorBaseline . . . . . . . . . . . . . . . . . . . . . 95
6.6.1 SamplingRate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.6.2 IntermediateFrequency . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.6.3 ArchitecturalImprovement . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.7 HDLComparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
6.8 HardwareTestResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.9 ResultsSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7 Conclusions 109
7.1 FutureWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
A AnalogCircuitDesignVerification 118
A.1 NoisePowerCalculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
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List of Figures
2.1 a)Asingle"point"scattererinthemainbeamofthetransmitandreceiveantennas.
b) Two scatterers used to illustrate how superposition applies to radar. c) Two
facetsarrangedinsuchawaythatthereceivedsignalhasscatteredoffofboth. . . . 6
2.2 Representativeradarblockdiagram. . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Examples of Radar Waveform Modulation: a) Unmodulated Pulse, b) Linear Fre-
quencyModulation(LFM),c)BinaryPhase-ShiftKeying(BPSK) . . . . . . . . . 11
2.4 RelativeSignalLevelsintheReceiver . . . . . . . . . . . . . . . . . . . . . . . . 14
2.5 RadarReceiverBlockDiagram . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.6 Data cube with analog data superimposed on the digital samples. Each column
contains the number of samples collected during a PRI spaced at the fast time
samplingrate. [31] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.7 Radarsignalrepresentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.8 a) Formatted stream of raw received data, b) Match filtered output, c) Result of
MatchedfilteringandDopplerProcessing . . . . . . . . . . . . . . . . . . . . . . 24
2.9 ExampleresultfromaPulseDopplerradar. . . . . . . . . . . . . . . . . . . . . . 25
3.1 Coaxial delay line based target generator architecture. Repeaters are inserted be-
tweensectionsofcoaxiallinetoovercomethesignificantattenuationcharacteristic
ofcoaxialcable. Notethefinalsectionofdelaylineisvariableinlength. . . . . . . 28
3.2 Fiber optic delay line based target generator architecture [22]. Note the delay
mediaisvariableinlength. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
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3.3 General laboratory digital target generator diagram. The figure includes optional
multipledigitalkernelstofacilitatemultipletargetsimulations. . . . . . . . . . . . 33
3.4 MemoryOnlyconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.5 Memory Read and Write Process Illustration. The target is stationary between a)
andb)andismovingbetweenb)andc). . . . . . . . . . . . . . . . . . . . . . . . 36
3.6 MemoryandSSBModulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.7 MemoryandSSBModulatorwithFineDelay . . . . . . . . . . . . . . . . . . . . 42
4.1 Frequency-tunableDDSSystem,reproducedfrom[9]. . . . . . . . . . . . . . . . 54
5.1 KC705andFMC150HighLevelBlockDiagram . . . . . . . . . . . . . . . . . . 59
5.2 CompleteSystemHighLevelBlockDiagram . . . . . . . . . . . . . . . . . . . . 61
5.3 CompleteDiagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.4 TopLevelTargetGeneratorAlgorithm . . . . . . . . . . . . . . . . . . . . . . . . 65
5.5 DetailofAddressControlBlock . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.6 DetailofSSBMixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.7 HilbertFIRMagnitude,Phase,andImpulseResponses . . . . . . . . . . . . . . . 70
5.8 SSBModulatorOutputSidebandRejectionPerformanceComparison . . . . . . . 70
6.1 FrequencyDomainRepresentationoftheTransmittedWaveforms . . . . . . . . . 75
6.2 StaticTarget,Attenuation=21dB:(Left)-RangeCut,(Right)-DopplerCut . . . 79
6.3 StaticTarget-RangeCuts;(Left)Atten. =21dB,(Right)Atten. =119dB . . . . 80
6.4 StaticTarget,Atten. =119dB:(Left)-RangeCut,(Right)-DopplerCut . . . . . . 80
6.5 Moving Target,Basic Case, Atten. = 21dB: (Left) -Range Cut, (Right) -Doppler
Cut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.6 MovingTarget,BaseCase,Atten. =119dB:(Left)-RangeCut,(Right)-Doppler
Cut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.7 DopplerSpectrum,v=0.1v . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
base
6.8 DopplerSpectrum,v=0.3v . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
base
ix
6.9 DopplerSpectrum,v=0.5v . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
base
6.10 ComparisonofDopplerSpectrumwithofaSingleandMultipleTargetSimulation 89
6.11 ResultsofVariationofRangeResolution . . . . . . . . . . . . . . . . . . . . . . . 91
6.12 NaturalModelWithandWithoutWindowing . . . . . . . . . . . . . . . . . . . . 93
6.13 DopplerspectrumofQuantizedModelwithWindowing . . . . . . . . . . . . . . . 93
6.14 BaselineCasewithBPSK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.15 DopplerSpectrum,2f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
s
6.16 DopplerSpectrum,4f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
s
6.17 Comparisonofthreedifferentvaluesfor f . . . . . . . . . . . . . . . . . . . . . 98
IF
6.18 Variationof f withnoDopplercorrectionsuperimposedwithasincfuncionwith
IF
nullsat f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
∆a
6.19 Comparison of the Doppler spectrum of the Natural, Quantized, and Interpolated
Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.20 WindowedComparisonofNatural,Quantized,andInterpolatedModels . . . . . . 101
6.21 WindowedComparisonofInterpolationFactor . . . . . . . . . . . . . . . . . . . 103
6.22 ComparisonofQuantizedandHDLModels . . . . . . . . . . . . . . . . . . . . . 104
6.23 HardwareTestConfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.24 ComparisonofHardwareresultswithQuantizedModel . . . . . . . . . . . . . . . 106
A.1 SystemApproachtoNoiseTemperatureCalculation[39] . . . . . . . . . . . . . . 119
x