Title: Radar Remote Sensing
1Radar 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
2- 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)
3 Passive and active Remote Sensing 1/1
- Passive vs. Active Sensors
4Concept 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.
5 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!
6 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
7 MAANTIETEEN JA GEOLOGIAN LAITOS
8- 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!
9Concept of Radar (6/10)Passive Remote sensing
Active Remote Sensing
10Concept 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
11Concept of Radar (8/10)
12Concept of Radar (9/10)
- Surface Roughness
- Back-scattering increases with roughness
- Moisture content
- Back-scattering
- increases with moisture
- Topography
- Viewing geometry
- affects the signal
13Concept of Radar (10/10)
14Concept 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
15Optical Image Format and Characteristics (1/1)
Characteristics of Image
16SAR Image Format and Characteristics (1/6)
Raw data
Detected SAR image, Single Look Complex, (SLC)
17SAR 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.
18SAR 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.
19SAR Image Format and Characteristics (4/6)
20SAR Image Format and Characteristics (5/6)
21SAR Image Format and Characteristics
(6/6)Satellite Radar Systems available now and
into the future
22Software's are used in SAR (Radar Images
Processing) (1/6)
https//earth.esa.int/web/guest/home
23Software's are used in SAR (Radar Images
Processing) (2/6)
https//earth.esa.int/web/guest/home
24Software's are used in SAR (Radar Images
Processing) (3/6)NEST (NEW ESA SATELLITE TOOL
BOX)
25Software's are used in SAR (Radar Images
Processing)(4/6)NEST (NEW ESA SATELLITE TOOL
BOX)
26Software's are used in SAR (Radar Images
Processing)(5/6)NEST (NEW ESA SATELLITE TOOL
BOX)
27Software's are used in SAR (Radar Images
Processing)(6/6)GAMMA Remote sensing
28Software's are used in SAR (Radar Images
Processing)(6/6)
29Video 1Video 2