Low-Angle Radar Land Clutter-Measurements and Empirical Models.: Low-Angle_Radar_Land_Clutter_-_Measurements_and_Empirical_Models.part2.rar

Low-Angle Radar Land Clutter-Measurements and Empirical Models.

Preface
Radar land clutter constitutes the unwanted radar echoes returned from the earth’s surface
that compete against and interfere with the desired echoes returned from targets of
interest, such as aircraft or other moving or stationary objects. To be able to
knowledgeably design and predict the performance of radars operating to provide
surveillance of airspace, detection and tracking of targets, and other functions in land
clutter backgrounds out to the radar horizon, radar engineers require accurate descriptions
of the strengths of the land clutter returns and their statistical attributes as they vary from
pulse to pulse and cell to cell. The problem of bringing statistical order and predictability
to land clutter is particularly onerous at the low angles (at or near grazing incidence) at
which surface-sited radars illuminate the clutter-producing terrain, where the fundamental
difficulty arising from the essentially infinite variability of composite terrain is
exacerbated by such effects as specularity against discrete clutter sources and intermittent
shadowing. Thus, predicting the effects of low-angle land clutter in surface radar was for
many years a major unsolved problem in radar technology.
Based on the results of a 20-year program of measuring and investigating low-angle land
clutter carried out at Lincoln Laboratory, Massachusetts Institute of Technology, this book
advances the state of understanding so as to “solve the low-angle clutter problem” in many
important respects. The book thoroughly documents all important results of the Lincoln
Laboratory clutter program. These results enable the user to predict land clutter effects in
surface radar.
This book is comprehensive in addressing the specific topic of low-angle land clutter
phenomenology. It contains many interrelated results, each important in its own right, and
unifies and integrates them so as to add up to a work of significant technological innovation
and consequence. Mean clutter strength is specified for most important terrain types (e.g.,
forest, farmland, mountains, desert, urban, etc.). Information is also provided specifying
the statistical distributions of clutter strength, necessary for determining probabilities of
detection and false alarm against targets in clutter backgrounds. The totality of clutter
modeling information so presented is parameterized, not only by the type of terrain giving
rise to the clutter returns, but also (and importantly) by the angle at which the radar
illuminates the ground and by such important radar parameters as carrier frequency, spatial
resolution, and polarization. This information is put forward in terms of empirical clutter
models. These include a Weibull statistical model for prediction of clutter strength and an
exponential model for the prediction of clutter Doppler spreading due to wind-induced
intrinsic clutter motion. Also included are analyses and results indicating, given the
strength and spreading of clutter, to what extent various techniques of clutter cancellation
can reduce the effects of clutter on target detection performance.
The empirically-derived clutter modeling information thus provided in this book utilizes
easy-to-understand formats and easy-to-implement models. Each of the six chapters is
essentially self-contained, although reading them consecutively provides an iterative
pedagogical approach that allows the ideas underlying the finalized modeling information
of Chapters 5 and 6 to be fully explored. No difficult mathematics exist to prevent easy
xvi Preface
assimilation of the subject matter of each chapter by the reader. The technical writing style
is formal and dedicated to maximizing clarity and conciseness of presentation. Meticulous
attention is paid to accuracy, consistency, and correctness of results. No further prerequisite
requirements are necessary beyond the normal knowledge base of the working radar
engineer (or student) to access the information of this book. A fortuitous combination of
national political, technological, and economic circumstances occurring in the late 1970s
and early 1980s allowed the Lincoln Laboratory land clutter measurement project to be
implemented and thereafter continued in studies and analysis over a 20-year period. It is
highly unlikely that another program of the scope of the Lincoln Laboratory clutter
program will take place in the foreseeable future. Future clutter measurement programs are
expected to build on or extend the information of this book in defined specific directions,
rather than supersede this information. Thus this book is expected to be of long-lasting
significance and to be a definitive work and standard reference on the subject of land clutter
phenomenology.
A number of individuals and organizations provided significant contributions to the Phase
Zero/Phase One land clutter measurements and modeling program at Lincoln Laboratory
and consequently towards bringing this book into existence and affecting its final form and
contents. This program commenced at Lincoln Laboratory in 1978 under sponsorship from
the Defense Advanced Research Projects Agency. The United States Air Force began joint
sponsorship several years into the program and subsequently assumed full sponsorship over
the longer period of its complete duration. The program was originally conceived by Mr.
William P. Delaney of Lincoln Laboratory, and largely came into focus in a short 1977
DARPA/USAF-sponsored summer study requested by the Department of Defense and
directed by Mr. Delaney. The Phase Zero/Phase One program was first managed at Lincoln
Laboratory by Mr. Carl E. Nielsen Jr. and by Dr. David L. Briggs, and subsequently by Dr.
Lewis A. Thurman and Dr. Curtis W. Davis III.
Early site selection studies for the Phase Zero/Phase One program indicated the desirability
of focusing measurements in terrain of relatively low relief and at northern latitudes such as
generally occurs in the prairie provinces of western Canada. As a result, a Memorandum of
Understanding (MOU) was established between the United States and Canada
implementing a joint clutter measurements program in which Canada, through Defence
Research Establishment Ottawa, was to provide logistics support and share in the measured
data and results. Dr. Hing C. Chan was the principal investigator of the clutter data at
DREO. Dr. Chan became a close and valued member of the Phase One community; many
useful discussions and interactions concerning the measured clutter data and its analysis
occurred between Dr. Chan and the author down to the time of present writing. Substantial
contracted data analysis support activity was provided to Dr. Chan by AIT Corporation,
Ottawa. Information descriptive of the terrain at the clutter measurement sites was provided
in a succession of contracted studies at Intera Information Technologies Ltd., Calgary.
The government of the United Kingdom through its Defence Evaluation Research Agency
became interested in the Lincoln Laboratory clutter program shortly after its
commencement. DERA subsequently became involved in the analysis of Phase One clutter
data under the aegis of The Technical Cooperation Program (TTCP), an international
defense science technical information exchange program. The U.S./Canada MOU was
terminated at the completion of measurements, and the sharing of the measurement data
and its analysis was thereafter continued between all three countries under TTCP.
Preface xvii
Significant analyses of selected subsets of the Phase One measurement data occurred with
DERA sponsorship in the U.K. at Smith Associates Limited and at GEC Marconi Research
Centre. The principal coordinator of these interactions at DERA was Mr. Robert A.
Blinston. Mr. John N. Entzminger Jr., former Director of the Tactical Technology Office at
DARPA, provided much encouragement to these joint U.S./Canada/U.K. clutter study
interactions in his role as head of the U.S. delegation to Subgroup K (radar) in TTCP.
In its early years, the Lincoln Laboratory clutter program was followed by Mr. David K.
Barton, then of Raytheon Company, now of ANRO Engineering, who stimulated our
thinking with his insights on the interrelationships of clutter and propagation and
discussions on approaches to clutter modeling. Also in the early years of the clutter
program, several interactions with Mr. William L. Simkins of the Air Force Research
Laboratory, Rome, N.Y., influenced methodology to develop correctly at Lincoln
Laboratory in such matters as clutter data reduction and intrinsic-motion clutter spectral
modeling. In the latter years of the Phase One program, Professor Alfonso Farina of Alenia
Marconi Systems, Italy, became interested in the clutter data. An informal collaboration
was organized by Professor Farina in which some particular Phase One clutter data sets
were provided to and studied by him and his colleagues at the University of Pisa and
University of Rome. These studies were from the point of view of signal processing and
target detectability in ground clutter backgrounds. A number of jointly-authored technical
journal papers in the scientific literature resulted.
The five-frequency Phase One clutter measurement equipment was fabricated by the General
Electric Co., Syracuse, N.Y. (now part of Lockheed Martin Corporation). Key members of
the Phase One measurements crew were Harry Dence and Joe Miller of GE, Captain Ken
Lockhart of the Canadian Forces, and Jerry Anderson of Intera. At Lincoln Laboratory, the
principal people involved in the management and technical interface with GE were David
Kettner and John Hartt. The project engineer of the precursor X-band Phase Zero clutter
program was Ovide Fortier. People who had significant involvement in data reduction and
computer programming activities include Gerry McCaffrey, Paul Crochetiere, Ken Gregson,
Peter Briggs, Bill Dustin, Bob Graham-Munn, Carol Bernhard, Kim Jones, Charlotte Schell,
Louise Moss, and Sharon Kelsey. Dr. Seichoong Chang served in an important consultant
role in overseeing the accurate calibration of the clutter data. Many informative discussions
with Dr. Serpil Ayasli helped provide understanding of the significant effects of
electromagnetic propagation in the clutter data. Application of the resultant clutter models in
radar system studies took place under the jurisdiction of Dr. John Eidson.
The original idea that the results of the Lincoln Laboratory clutter program could be the
basis of a clutter reference book valuable to the radar community at large came from Mr.
Delaney. Dr. Merrill I. Skolnik, former Superintendent of the Radar Division at the Naval
Research Laboratory in Washington, D.C., lent his support to this book idea and provided
encouragement to the author in his efforts to follow through with it. When a first rough
draft of Chapter 1 of the proposed book became available, Dr. Skolnik kindly read it and
provided a number of constructive suggestions. Throughout the duration of the clutter book
project, Dr. Thurman was a never-failing source of positive managerial support and
insightful counsel to the author on how best to carry the book project forward. Mr. C.E.
Muehe provided a thorough critical review of the original report material upon which much
of Chapter 6 is based. Dr. William E. Keicher followed the book project in its later stages
and provided a technical review of the entire book manuscript. Skillful typing of the
xviii Preface
original manuscript of this book was patiently and cheerfully performed through its many
iterations by Gail Kirkwood. Pat DeCuir typed many of the original technical reports upon
which the book is largely based. Members of the Lincoln Laboratory Publications group
maintained an always positive and most helpful approach in transforming the original
rough manuscript into highly finished form. These people in particular include Deborah
Goodwin, Jennifer Weis, Dorothy Ryan, and Katherine Shackelford. Dudley R. Kay,
president of SciTech Publishing and vice-president at William Andrew Publishing, and the
book’s compositors, Lynanne Fowle and Robert Kern at TIPS Technical Publishing, ably
and proficiently met the many challenges in successfully seeing the book to press.
It is a particular pleasure for the author to acknowledge the dedicated and invaluable
assistance provided by Mr. John F. Larrabee (Lockheed Martin Corporation) in the day-today
management, reduction, and analyses of the clutter data at Lincoln Laboratory over the
full duration of the project. In the latter days of the clutter project involving the production
of this book, Mr. Larrabee managed the interface to the Lincoln Laboratory Publications
group and provided meticulous attention to detail in the many necessary iterations required
in preparing all the figures and tables of the book. Mr. Larrabee recently retired after a long
professional career in contracted employment at Lincoln Laboratory, at about the time the
book manuscript was being delivered to the publisher.
Many others contributed to the land clutter project at Lincoln Laboratory. Lack of explicit

Contents
Foreword xiii
Preface xv
Chapter 1 Overview 1
1.1 Introduction 1
1.2 Historical Review 3
1.2.1 Constant σ° 4
1.2.2 Wide Clutter Amplitude Distributions 5
1.2.3 Spatial Inhomogeneity/Resolution Dependence 6
1.2.4 Discrete Clutter Sources 8
1.2.5 Illumination Angle 9
1.2.6 Range Dependence 11
1.2.7 Status 13
1.3 Clutter Measurements at Lincoln Laboratory 13
1.4 Clutter Prediction at Lincoln Laboratory 16
1.4.1 Empirical Approach 17
1.4.2 Deterministic Patchiness 18
1.4.3 Statistical Clutter 18
1.4.4 One-Component σ° Model 18
1.4.5 Depression Angle 19
1.4.6 Decoupling of Radar Frequency and Resolution 20
1.4.7 Radar Noise Corruption 21
1.5 Scope of Book 23
1.5.1 Overview 23
1.5.2 Two Basic Trends 24
1.5.3 Measurement-System-Independent Clutter Strength 24
1.5.4 Propagation 24
1.5.5 Statistical Issues 25
1.5.6 Simpler Models 26
1.5.7 Parameter Ranges 26
1.6 Organization of Book 27
References 30
Chapter 2 Preliminary X-Band Clutter Measurements 35
2.1 Introduction 35
2.1.1 Outline 35
2.2 Phase Zero Clutter Measurements 36
2.2.1 Radar Instrumentation 36
2.2.2 Measurement Sites 37
2.2.3 Terrain Description 37
viii Contents
2.3 The Nature of Low-Angle Clutter 42
2.3.1 Clutter Physics I 42
2.3.2 Measured Land Clutter Maps 44
2.3.3 Clutter Patches 46
2.3.4 Depression Angle 55
2.3.5 Terrain Slope/Grazing Angle 62
2.3.6 Clutter Modeling 65
2.4 X-Band Clutter Spatial Amplitude Statistics 68
2.4.1 Amplitude Distributions by Depression
Angle for Three General Terrain Types 68
2.4.2 Clutter Results for More Specific Terrain Types 77
2.4.3 Combining Strategies 96
2.4.4 Depression Angle Characteristics 101
2.4.5 Effect of Radar Spatial Resolution 110
2.4.6 Seasonal Effects 111
2.5 Summary 115
References 116
Appendix 2.A Phase Zero Radar 118
Appendix 2.B Formulation of Clutter Statistics 126
Reference 138
Appendix 2.C Depression Angle Computation 139
Reference 141
Chapter 3 Repeat Sector Clutter Measurements 143
3.1 Introduction 143
3.1.1 Outline 144
3.2 Multifrequency Clutter Measurements 145
3.2.1 Equipment and Schedule 146
3.2.2 Data Collection 146
3.2.3 Terrain Description 156
3.3 Fundamental Effects in Low-Angle Clutter 160
3.3.1 Clutter Physics II 160
3.3.2 Trends with Radar Frequency 162
3.3.3 Depression Angle and Terrain Slope 165
3.4 Mean Land Clutter Strength vs Frequency
by Terrain Type 168
3.4.1 Detailed Discussion of Measurements 169
3.4.2 Twelve Multifrequency Clutter Strength
Characteristics 204
3.5 Dependencies of Mean Land Clutter Strength
with Radar Parameters 209
3.5.1 Frequency Dependence 209
3.5.2 Polarization Dependence 212
3.5.3 Resolution Dependence 216
3.6 Higher Moments and Percentiles in Measured Land
Contents ix
Clutter Spatial Amplitude Distributions 222
3.6.1 Ratio of Standard Deviation-to-Mean 222
3.6.2 Skewness and Kurtosis 227
3.6.3 Fifty-, 70-, and 90-Percentile Levels 228
3.7 Effects of Weather and Season 231
3.7.1 Diurnal Variability 234
3.7.2 Six Repeated Visits 235
3.7.3 Temporal and Spatial Variation 237
3.8 Summary 242
References 246
Appendix 3.A Phase One Radar 247
Appendix 3.B Multipath Propagation 259
References 272
Appendix 3.C Clutter Computations 274
Chapter 4 Approaches to Clutter Modeling 285
4.1 Introduction 285
4.1.1 Modeling Objective 287
4.1.2 Modeling Rationale 288
4.1.3 Modeling Scope 291
4.2 An Interim Angle-Specific Clutter Model 292
4.2.1 Model Basis 292
4.2.2 Interim Model 294
4.2.3 Error Bounds 297
4.3 Non-Angle-Specific Modeling Considerations 299
4.3.1 Phase Zero Results 299
4.3.2 Simple Clutter Model 302
4.3.3 Further Considerations 305
4.3.4 Summary 309
4.4 Terrain Visibility and Clutter Occurrence 312
4.4.1 Effects of Trees on Visibility at Cold Lake 312
4.4.2 Decreasing Shadowing with Increasing
Site Height 315
4.4.3 Vertical Objects on Level Terrain at Altona 317
4.4.4 Summary 319
4.5 Discrete vs Distributed Clutter 320
4.5.1 Introduction 320
4.5.2 Discrete Clutter Sources at Cochrane 324
4.5.3 Separation of Discrete Source at Suffield 325
4.5.4 σ vs σ° Normalization 330
4.5.5 Conclusions 333
4.6 Temporal Statistics, Spectra, and Correlation 334
4.6.1 Temporal Statistics 335
4.6.2 Spectral Characteristics 335
4.6.3 Correlative Properties 338
x Contents
4.7 Summary 343
References 347
Appendix 4.A Clutter Strength vs Range 350
Appendix 4.B Terrain Visibility as a Function of
Site Height and Antenna Mast Height 359
Appendix 4.C Effects of Terrain Shadowing and
Finite Sensitivity 371
Appendix 4.D Separation of Discretes in
Clutter Modeling 396
Chapter 5 Multifrequency Land Clutter
Modeling Information 407
5.1 Introduction 407
5.1.1 Review 408
5.2 Derivation of Clutter Modeling Information 416
5.2.1 Weibull Statistics 416
5.2.2 Clutter Model Framework 418
5.2.3 Derivation of Results 420
5.3 Land Clutter Coefficients for General Terrain 429
5.3.1 General Mixed Rural Terrain 429
5.3.2 Further Reduction 437
5.3.3 Validation of Clutter Model Framework 439
5.3.4 Simplified Clutter Prediction 440
5.4 Land Clutter Coefficients for Specific Terrain Types 440
5.4.1 Urban or Built-Up Terrain 443
5.4.2 Agricultural Terrain 492
5.4.3 Forest Terrain 506
5.4.4 Shrubland Terrain 518
5.4.5 Grassland Terrain 521
5.4.6 Wetland Terrain 526
5.4.7 Desert Terrain 529
5.4.8 Mountainous Terrain 537
5.5 PPI Clutter Map Prediction 542
5.5.1 Model Validation 543
5.5.2 Model Improvement 543
5.6 Summary 544
References 546
Appendix 5.A Weibull Statistics 548
References 573
Chapter 6 Windblown Clutter Spectral Measurements 575
6.1 Introduction 575
6.2 Exponential Windblown Clutter Spectral Model 576
6.2.1 ac Spectral Shape 577
Contents xi
6.2.2 dc/ac Ratio 579
6.2.3 Model Scope 581
6.3 Measurement Basis for Clutter Spectral Model 582
6.3.1 Radar Instrumentation and Data Reduction 582
6.3.2 Measurements Illustrating ac Spectral Shape 589
6.3.3 Measured Ratios of dc/ac Spectral Power 600
6.4 Use of Clutter Spectral Model 604
6.4.1 Spreading of σ ° in Doppler 604
6.4.2 Two Regions of Spectral Approximation 606
6.4.3 Cells in Partially Open or Open Terrain 609
6.4.4 MTI Improvement Factor 616
6.5 Impact on MTI and STAP 620
6.5.1 Introduction 620
6.5.2 Impact on Performance of Optimum MTI 621
6.5.3 Impact on STAP Performance 625
6.5.4 Validation of Exponential Clutter
Spectral Model 635
6.6 Historical Review 639
6.6.1 Three Analytic Spectral Shapes 639
6.6.2 Reconciliation of Exponential Shape
with Historical Results 659
6.6.3 Reports of Unusually Long Spectral Tails 664
6.7 Summary 674
References 677
Index 683

Low-Angle Radar Land Clutter-Measurements and Empirical Models

Low-Angle Radar Land Clutter-Measurements and Empirical Models

Low-Angle Radar Land Clutter-Measurements and Empirical Models

Low-Angle Radar Land Clutter-Measurements and Empirical Models

：8de

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169-284     441-575

往往很难找的东西，在这却很好得！太谢谢了

Fantastic ... ... Fancy ... .

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感谢楼主分享，分享万岁

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感谢楼主无私奉献

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Design and Analysis of Modern Tracking Systems

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