Table of Contents

Chapter 1 Introduction to Remote Sensing

1.1 Order of Battle

     1.1.1 Air order of battle

     1.1.2 Electronic order of battle

     1.1.3 Space order of battle

     1.1.4 Naval order of battle

     1.1.5 Industrial order of battle

1.2 Technology Survey

     1.2.1 Imaging the whole earth: optical and infrared imaging

     1.2.2 Earth resources systems: 30-m pixels

     1.2.3 Higher resolution: 1-3-m ground sample distance

     1.2.4 High-resolution airborne imagery

     1.2.5 Synthetic aperture radar (SAR)

1.3 Three Axes

1.4 Resources

1.5 Problems

Chapter 2 Electromagnetic Basics

2.1 The Electromagnetic Spectrum

     2.1.1 Maxwell's equations

2.2 Polarization of Radiation

2.3 Energy in Electromagnetic Waves

     2.3.1 Photoelectric effect

     2.3.2 Photomultiplier tubes

2.4 Sources of Electromagnetic Radiation

     2.4.1 Line spectra

     2.4.2 Blackbody radiation

2.5 Electromagnetic-Radiation-Matter Interactions

     2.5.1 Transmission

     2.5.2 Reflection

     2.5.3 Scattering

     2.5.4 Absorption

2.6 Problems

Chapter 3 Optical Imaging

3.1 The First Remote-Sensing Satellite: Corona

     3.1.1 History

     3.1.2 Technology

     3.1.3 Illustrations

3.2 Atmospheric Absorption, Scattering, and Turbulence

     3.2.1 Atmospheric absorption: wavelength dependence

     3.2.2 Atmospheric scattering

     3.2.3 Atmospheric turbulence

3.3 Basic Geometrical Optics

     3.3.1 Focal length/geometry

     3.3.2 Optical diagram: similar triangles and magnification

     3.3.3 Aperture (f/stop)

     3.3.4 Image formation by lens or pinhole

3.4 Diffraction Limits: The Rayleigh Criterion

3.5 Detectors

     3.5.1 Solid state

     3.5.2 Focal plane arrays

     3.5.3 Uncooled focal planes: microbolometers

3.6 Imaging System Types, Telemetry, and Bandwidth

     3.6.1 Imaging system types

3.7 Telemetry Strategies

     3.7.1 Direct downlink

     3.7.2 Relay

     3.7.3 Store and dump

3.8 Bandwidth and Data Rates

3.9 Problems

Chapter 4 Optical Satellite Systems

4.1 Hubble: The Big Telescope

     4.1.1 The Hubble satellite

     4.1.2 The Hubble telescope design

     4.1.3 The Hubble detectors: Wide-Field and Planetary Camera 2

     4.1.4 The repair missions

     4.1.5 Operating constraints

4.2 Commercial Remote Sensing: IKONOS and Quickbird

     4.2.1 IKONOS satellite

     4.2.2 NOB with IKONOS: Severodvinsk

4.3 The Earth at Night

4.4 Exposure Times

4.5 Problems

Chapter 5 Orbital Mechanics Interlude

5.1 Gravitational Force

5.2 Circular Motion

     5.2.1 Equations of motion

     5.2.2 Centripetal force

5.3 Satellite Motion

     5.3.1 Illustration: geosynchronous orbit

5.4 Kepler's laws

     5.4.1 Elliptical orbits

     5.4.2 Equal areas are swept out in equal times

     5.4.3 Orbital period: τ² ∝ r³

5.5 Orbital Elements

     5.5.1 Semi-major axis

     5.5.2 Eccentricity

     5.5.3 Inclination angle

     5.5.4 Right ascension of the ascending node

     5.5.5 Closest point of approach (argument of perigee)

5.6 A Few Standard Orbits

     5.6.1 Low-earth orbit

     5.6.2 Medium-earth orbit

     5.6.3 Geosynchronous orbit

     5.6.4 Molniya (high-earth) orbit

     5.6.5 Summary of orbital values

5.7 Bandwidth, Revisited

5.8 Problems

Chapter 6 Spectral and Polarimetric Imagery

6.1 Reflectance of Materials

6.2 Human Visual Response

6.3 Spectral Technologies

6.4 Landsat

     6.4.1 Landsat orbit

     6.4.2 Landsat sensors

     6.4.3 Landsat data links

6.5 Spectral Responses for the Commercial Systems

6.6 Analysis of Spectral Data: Band Ratios and NDVI

6.7 Analysis of Spectral Data: Color Space and Spectral Angles

6.8 Imaging Spectroscopy

     6.8.1 AVIRIS

     6.8.2 Hyperion

     6.8.3 MightySat II: Fourier-Transform Hyperspectral Imager

6.9 Optical Polarization

6.10 Problems

Chapter 7 Image Analysis

7.1 Interpretation Keys (Elements of Recognition)

     7.1.1 Shape

     7.1.2 Size

     7.1.3 Shadow

     7.1.4 Height (depth)

     7.1.5 Tone or color

     7.1.6 Texture

     7.1.7 Pattern

     7.1.8 Association

     7.1.9 Site

     7.1.10 Time

7.2 Image Processing

     7.2.1 Univariate statistics

     7.2.2 Dynamic range: snow and black cats

7.3 Histograms and Target Detection

7.4 Multi-dimensional Data: Multivariate Statistics

7.5 Filters

     7.5.1 Smoothing

     7.5.2 Edge detection

7.6 Supplemental Notes on Statistics

7.7 Problems

Chapter 8 Thermal Infrared

8.1 IR Basics

     8.1.1 Planck's radiation formula

     8.1.2 Stefan-Boltzmann: radiance αT⁴

     8.1.3 Wien's displacement law

     8.1.4 Emissivity

     8.1.5 Atmospheric absorption

8.2 Radiometry

     8.2.1 Point source radiometry

     8.2.2 Radiometry for resolved targets

8.3 More IR Terminology and Concepts

     8.3.1 Signal-to-noise ratio: NEΔT

     8.3.2 Kinetic temperature

     8.3.3 Thermal inertia, conductivity, capacity, and diffusivity

8.4 Landsat

8.5 Early Weather Satellites

     8.5.1 TIROS

     8.5.2 Nimbus

8.6 GOES

     8.6.1 Satellite and sensor

     8.6.2 Shuttle launch: vapor trail and rocket

8.7 Defense Support Program

8.8 SEBASS: Thermal Spectral

     8.8.1 Hard targets

     8.8.2 Gas measurements: Kilauea, Pu 'u 'O 'o vent

8.9 Problems

Chapter 9 Radio Detection and Ranging (Radar)

9.1 Imaging Radar

     9.1.1 Imaging radar basics

9.2 Radar Resolution

     9.2.1 Range resolution

     9.2.2 Signal modulation

     9.2.3 Azimuth resolution

     9.2.4 Beam pattern and resolution

     9.2.5 Synthetic-aperture radar

9.3 Radar Cross-Section σ and Polarization

9.4 Radar Range Equation

9.5 Wavelength

9.6 SAR Image Elements

     9.6.1 Dielectric constant: soil moisture

     9.6.2 Roughness

     9.6.3 Tetrahedrons and corner reflectors: the cardinal effect

9.7 Problems

Chapter 10 Radar Systems and Applications

10.1 Shuttle Imaging Radar

10.2 Soil Penetration

10.3 Ocean Surface and Shipping

     10.3.1 SIR-C: oil slicks and internal waves

     10.3.2 RADARSAT: ship detection

     10.3.3 TerraSar-X: Gibraltar

     10.3.4 ERS-1: ship wakes and Doppler effects

10.4 Multi-temporal Images: Rome

10.5 Sandia Ku-Band Airborne Radar: Very High Resolution

10.6 Radar Interferometry

     10.6.1 Coherent change detection

     10.6.2 Topographic mapping

10.7 The Shuttle Radar Topographic Mapping (SRTM) Mission

     10.7.1 Mission design

     10.7.2 Mission results: level-2 terrain-height datasets (digital topographic maps)

10.8 TerraSAR-X and TanDEM-X

10.9 Problems

Chapter 11 Light Detection And Ranging

11.1 Introduction

11.2 Physics and Technology: Airborne and Terrestrial Scanners

     11.2.1 Lasers and detectors

     11.2.2 Laser range resolution

11.3 Airborne and Terrestrial Systems

     11.3.1 Airborne Oceanographic LiDAR

     11.3.2 Commercial LiDAR systems

11.4 Point Clouds and Surface Models

11.5 Bathymetry

11.6 LiDAR from Space

11.7 Problems

Appendix 1 Derivations

A1.1 Derivation of the Bohr Atom

A1.2 Dielectric Theory

A1.3 Derivation of the Beam Pattern for a Square Aperture

Appendix 2 Corona

A2.1 Mission Overview

A2.2 Camera Data

A2.3 Mission Summary

A2.4 Orbits: An Example

Appendix 3 Tracking and Data-Relay Satellite System

A3.1 Relay Satellites: TDRSS

A3.2 White Sands

A3.3 TDRS 1-7

A3.4 TDRS 8-10

A3.5 TDRS K, L, M

Appendix 4 Useful Equations and Constants

Preface

This text is designed to meet the needs of students interested in remote sensing as a tool for the study of military and intelligence problems. It focuses on the technology of remote sensing, both for students who will be working in systems acquisition offices and for those who might eventually need to be "informed consumers" of the products derived from remote sensing systems. I hope it will also be useful for those who eventually work in this field. Here in the second edition, the book maintains, as much as possible, a focus on the physics of remote sensing. As a physicist, I'm more interested in the technology of acquiring data than the final applications. Therefore, this work differs from related textbooks that favor civilian applications, particularly geology, agriculture, weather (atmosphere), and oceanography. I have instead concentrated on satellite systems, including power, data storage, and telemetry systems, because this knowledge is important for those trying to develop new remote sensing systems. For example, one of the ongoing themes is how bandwidth constraints define what you can and cannot do in terms of remote sensing.

From a tactical perspective, low-spatial-resolution systems are not very interesting, so this text focuses on systems with high spatial resolution. This is not to deny the utility of, say, weather systems for the military, but that is a domain of a different sort, and one I leave to that community. (As a consequence, for example, I leave out passive microwave sensing as a topic.) Similarly, although oceanography is clearly important to the Navy, that too is a topic I leave to others. I have completely ignored the technology of film-based imaging systems, aside from a discussion of the historical reconnaissance satellite systems.

Part of the motivation for creating this textbook was and is the ongoing discrepancy between the content of such books and the current state of the art. When I started teaching remote sensing and crafting what has become this text, the IKONOS satellite had not yet been launched. At the time of publication of the first edition, there were no high-spatial-resolution imaging radar systems, but now I have an illustration from TerraSAR-X at a 30-cm resolution. The launch of SkySat 1 by Skybox Imaging (now Terra Bella, a Google company, as of November 21, 2013) clearly signals many upcoming changes in imaging from space that are not ready to be discussed here. These larger fleets of satellites and newer focal plane technology imply more persistent imaging. Video from space is a consequence of these new hardware designs, with promising but uncertain utility. Also signaled by the success of Skybox imaging: remote sensing appears to be emerging as the third field, following communications and navigation, to become economically viable in space. This text is organized according to a fairly typical progression - visible optical systems in the visible realm, followed by infrared and radar systems. New to this textbook is a full chapter on LiDAR. The necessary physics is developed for each domain, followed by a look at a few operational systems that are appropriate. Somewhat unusual for a text of this sort is a chapter on how orbital mechanics influences remote sensing, but ongoing experience shows that this topic is essential.

I have added a radiometry component to the infrared (IR), radar (SAR), and LiDAR sections. The IR section clearly needed this to address detection issues and make temperature measurements more clearly founded. The imaging radar material clearly needed the radar range equation, just as the LiDAR chapter needed its corresponding range equation.

Finally: The first edition was pretty much a solo effort on my part. The second edition has benefitted from the support of my technical team - my thanks to Angela Kim, Jeremy Metcalf, Chad Miller, and Scott Runyon for their contributions. Thanks to Donna Aikens and Jean Ferreira for help with the many copyright issues. The reviewers did a great job and identified a number of annoying elements in my writing style that clearly needed to be adjusted. Thanks to the editor, Scott McNeill, for his persistence and diligence.

R. C. Olsen
Naval Postgraduate School, Monterey, CA
June 2016