Radar Remote Sensing

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Radar Remote Sensing By Falah Fakhri
Post-doctoral Scholar falah.fakhri_at_utu.fi
https//www.researchgate.net/profile/Falah_Fakhri
https//falahfakhri.wordpress.com
https//twitter.com/FALAHFAKHRI? Department of
Geography and Geology

Tuesday 26/08/2014 Time 1400 1500
MAANTIETEEN JA GEOLOGIAN LAITOS
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• Seminars outline
• Passive and active Remote Sensing
• Concept of Radar
• Concept of SAR
• Optical Image Format and Characteristics
• SAR Image Format and Characteristics
• Amplitude
• Phase
• Images acquisitions
• Software's are used in SAR (Radar Images
  Processing)

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Passive and active Remote Sensing 1/1

• Passive vs. Active Sensors

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Concept of Radar (1/10)

• Echolocation
• is the use of
• sound waves and
• echoes to determine
• where objects are in space.
• Bats use echolocation to navigate and find food
  in the dark. To echolocate, bats send out sound
  waves from their mouth or nose. When the sound
  waves hit an object they produce echoes. The echo
  bounces off the object and returns to the bats
  ears. Bats listen to the echoes to figure out
  where the object is, how big it is, and its
  shape.

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Concept of Radar (2/10)

• Imagine you are in the Grand Valley and you
  shout. The cliffs will reflect the sound wave.
  After some time you will hear an echo, which is
  not exactly the same compared to what you
  shouted. This is the principle of a radar!

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Concept of Radar (3/10)

• RADAR stands for Radio Detection and Ranging so
  what is a Radar?
• A (Imaging) Radar is an active system that uses
  a transmitter to illuminate a scene. The pulses
  sent are microwaves, i.e. a wave with an
  amplitude and a phase, having a certain frequency
  and polarization.
• The radar then records the echo or
• (backscatters)
• scattered back from the objects/targets
• B Non imaging

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• Concept of Radar (4/10)

MAANTIETEEN JA GEOLOGIAN LAITOS
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• Concept of Radar (5/10)
• radars illuminate the target
• so that they
• can operate day and night.
• Microwave frequencies
• Electromagnetic
• waves penetrate to
• Some extent through media.
• At most frequencies clouds are
• transparent!
• Complex interaction with medium or
• target
• a Radar image is not a photo!

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Concept of Radar (6/10)Passive Remote sensing


Active Remote Sensing
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Concept of Radar (7/10)interaction with medium
or targets
The transmitted pulse
interacts with the
Earth surface and only
a portion of it is
backscattered to the
receiving antenna
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Concept of Radar (8/10)
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Concept of Radar (9/10)

• Surface Roughness
• Back-scattering increases with roughness
• Moisture content
• Back-scattering
• increases with moisture
• Topography
• Viewing geometry
• affects the signal

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Concept of Radar (10/10)
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Concept of SAR (1/1)

• Synthetic Aperture Radar (SAR)
• It has cloud-penetrating capabilities
• because it uses imaging system (Microwave
  frequencies
• Electromagnetic) waves.
• It has day and night and weather-independent
• operational capabilities because it is an active
  system.
• Finally, its interferometric configuration

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Optical Image Format and Characteristics (1/1)
Characteristics of Image
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SAR Image Format and Characteristics (1/6)
Raw data
Detected SAR image, Single Look Complex, (SLC)
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SAR Image Format and Characteristics (2/6)

• Amplitude
• The detected SAR image contains
• a measurement of the Amplitude
• (Intensity) of the radiation
• backscattered toward the radar by
• the objects (scatterers) contained in each SAR
  resolution
• cell.
• Typically, exposed rocks and urban areas show
  strong
• amplitude ( bright pixel) whereas smooth flat
  surface, like quiet water basins show low
  amplitude (dark pixels) since the
• Backscatters (radiation) is mainly measured away
  from the radar.

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SAR Image Format and Characteristics (3/6)

• Phase
• The pulses (radiation) transmitted
• from the radar has to reach the
• scatterers on the ground and then
• to comeback to the radar in order
• to form the SAR image.
• Scatterers at different distance from the radar
  introduce a different delay between transmission
  and reception of the radiation.

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SAR Image Format and Characteristics (4/6)

• Ascending

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SAR Image Format and Characteristics (5/6)

• Descending

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SAR Image Format and Characteristics
(6/6)Satellite Radar Systems available now and
into the future
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Software's are used in SAR (Radar Images
Processing) (1/6)
https//earth.esa.int/web/guest/home
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Software's are used in SAR (Radar Images
Processing) (2/6)
https//earth.esa.int/web/guest/home
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Software's are used in SAR (Radar Images
Processing) (3/6)NEST (NEW ESA SATELLITE TOOL
BOX)
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Software's are used in SAR (Radar Images
Processing)(4/6)NEST (NEW ESA SATELLITE TOOL
BOX)

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Software's are used in SAR (Radar Images
Processing)(5/6)NEST (NEW ESA SATELLITE TOOL
BOX)
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Software's are used in SAR (Radar Images
Processing)(6/6)GAMMA Remote sensing

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Software's are used in SAR (Radar Images
Processing)(6/6)

• ERDAS, 2014

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