2008 IEEE International Geoscience & Remote Sensing Symposium
July 6-11, 2008 | Boston, Massachusetts, U.S.A.

HD-8: Interferometric Synthetic Aperture Radar (InSAR) Methods and Applications

Sunday Morning, July 6, 08:30 - 12:30

Presented by

Howard Zebker, Stanford University

Outline

  1. What is a radar?
    • Early radars
    • Distance measurements
    • Mapping multiple objects - ppi
    • Imaging geometry
    • Forming an image
    • Radar block diagram
    • Imaging radar block diagram
  2. Radar equation
    • Antenna gain
    • Radar cross section
    • Radar equation requires cross section
    • Distributed targets: normalized cross section (s0) multiplied by pulse-limited area
    • Signal to noise ratio
    • The dB table
  3. Properties of an EM wave
    • Observables are frequency, amplitude, phase, and direction
    • Phasor notation drops explicit time dependence
    • Phase of an EM wave
    • Observed phase of a radar echo
  4. InSAR geometry and phase
    • Phase calculation
    • InSAR geometry
    • InSAR phase - topography
    • InSAR geometry - deformation
    • InSAR deformation phase
    • Phase noise
  5. Decorrelation
    • Baseline decorrelation
    • Temporal decorrelation
    • Rotational decorrelation
    • Unspecified noises in system
    • Thermal effects
    • Quantization
    • Decorrelation sources
    • Quantifying decorrelation
  6. Persistent scattering methods
    • Signal model
    • Phase source dependence
    • PS selection
    • Amplitude dispersion proxy for phase noise
    • Maximum likelihood selection
    • 3-D phase unwrapping
  7. InSAR applications
    • Earthquakes
      • Seismic, pre- and post-seismic motions
      • Examples
    • Volcanoes
      • Long Valley - interferograms and PS
      • Galapagos
      • Hawaii
    • Ice Mass balance
      • Volume scattering models
      • Accumulation in layered media
      • Accumulation rate
    • Hydrological studies
      • Las Vegas
      • Antelope Valley
      • San Luis Basin
    • Vegetation studies
      • Biomass
      • Canopy height

Abstract

Interferometric Synthetic Aperture Radar (InSAR) methods have found wide application for the measurement of Earth topography and surface deformation. Here we present basic InSAR theory and implementation strategies and how these affect radar system design, plus present newer processing methods such as persistent scattering. We then illustrate the theory with many examples from current literature. We will cover hardware issues, processing algorithms, and specific applications that illustrate advances in the technology over the past decade. Lectures will cover derivation of the basic formulas and details of how these may be implemented in practice. We will cover both conventional InSAR and persistent scattering methods, which permit InSAR coverage in areas of dense vegetation or over other decorrelating terrains. Applications we will examine include the study of earthquakes, volcanoes, subsidence from water withdrawal and oil extraction, and ecological research.

Speaker Biography

Howard Zebker is Professor of Geophysics and Electrical Engineering at Stanford University. His research addresses geophysical processes on the surfaces of the Earth and other planets using radar remote sensing methods. His specialization is interferometric radar, or InSAR, a technique to measure mm-scale surface deformation at fine resolution over wide areas. Dr. Zebker applies this technique primarily to the study of earthquakes, volcanoes, and human-induced subsidence. He also addresses global environmental problems by tracking the movement of ice in the polar regions, whose ice mass balance affects sea level rise and global climate. Other work includes participation in NASA space missions such as Cassini, where his group is now examining the largest moon of Saturn, Titan, to try and deduce its composition and evolution.