en-microwave remote sensing
TRANSCRIPT
Kishore Kumar Parida EC200117313 [1]
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Microwave Remote Sensing(MRS)
Presented by
Kishore Kumar Parida EC200117313
Under the guidance ofMr. Rowdra Ghatak
Kishore Kumar Parida EC200117313 [2]
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What is microwave remote sensing?
•A special application of microwave communications technologies for the purpose of collecting geophysical information about targets (objects and media) without making physical contact.
•Microwave reflections or emissions from earth materials bear no direct relationship to their counterparts in the visible portions of the spectrum.
Kishore Kumar Parida EC200117313 [3]
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•There is an interaction between the EM waves and matter.
•The target imposes a modulation on the EM wave which becomes its identifying characteristics.
•Sensors use microwave communications technologies.
•Active (radar) and passive (microwave radiometry) measurements.
How does it work?
Kishore Kumar Parida EC200117313 [4]
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•Passive: uses natural energy, either reflected sunlight or emitted thermal or microwave radiation
•Active: sensor creates its own energy
•Transmitted toward Earth
•Interacts with atmosphere and/or surface
•Reflects back toward sensor (backscatter)
Active and Passive Microwave Sensors
Kishore Kumar Parida EC200117313 [5]
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In the microwave region of the EM spectrum, the power collected by a microwave antenna is:
P blackbody = k Tb * bandwidth
Microwave Brightness Temperature, Tb, of a media is the product of the media emissivity and its physical temperature. For blackbodies, = 1.0Tb = * T phys
Microwave Radiometry
Kishore Kumar Parida EC200117313 [6]
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Microwave Radiometer
KB*(receiver gain)
Tsys = Radiometer Output power
Tsys = T ant + T RecWhere K=Boltzman’s constant
B=bandwidth
TRec = (1-NF)*290 K; NF=Receiver noise figure
Tant= scene brightness temp collected by antenna
Resistor noise
Antenna Receiver
Square Law detector
LPF
Trec
+
Kishore Kumar Parida EC200117313 [7]
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Radiative Transfer Theory
The TB measured by spaceborne radiometer is the linear sum of individual contributions from the atmosphere and surface
Kishore Kumar Parida EC200117313 [8]
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Defense Meteorological Support Program (DMSP)
Kishore Kumar Parida EC200117313 [9]
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Three Day Average of Some MRS Parameters
Kishore Kumar Parida EC200117313 [10]
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What is a Microwave Scatterometer?
•A special purpose radar sensor that measures scattering from the earth’s surface i.e., a scatter-meter
•If the objects are having smaller wavelengths,then scattering occurs
Kishore Kumar Parida EC200117313 [11]
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Satellite Microwave Scatterometer
Pr = Pt * σWhere σ = ocean Scattering coeff. Or Normalized radar Cross-section
Kishore Kumar Parida EC200117313 [12]
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Scatterometer Applications
•Ocean Wind Vector (wind speed & direction)• Hurricanes & Typhoons• Sea Ice Imaging• Land Imaging
Kishore Kumar Parida EC200117313 [13]
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Antarctic Sea Ice Imaging
Kishore Kumar Parida EC200117313 [14]
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Tropical Rainfall Measuring Mission (TRMM)
• Microwave remote sensing of rainfall• TRMM Microwave (Radiometer) Imager• Precipitation Radar
Kishore Kumar Parida EC200117313 [15]
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Greenland Ice Melt - 4 day intervals
Kishore Kumar Parida EC200117313 [16]
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Precipitation Radar - Hurricane Rainfall Image
Kishore Kumar Parida EC200117313 [17]
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Synthetic Aperture Radar
•Generally refers to the case of a moving radar and a stationary target- usually an extended scene, such as the surface of the Earth.
•ISAR refers to the case in which the radar is relatively stationary and a rotating target provides all(or most) of the motion to create the synthetic aperture.
Kishore Kumar Parida EC200117313 [18]
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Comparison Between RAR and SAR
Kishore Kumar Parida EC200117313 [19]
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Comparison Between RAR and SAR
Kishore Kumar Parida EC200117313 [20]
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SAR Modes
Kishore Kumar Parida EC200117313 [21]
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Side-Looking Radar System
Kishore Kumar Parida EC200117313 [22]
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SLR Operation
Kishore Kumar Parida EC200117313 [23]
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Conclusion
•microwave sensors provide valuable geophysical measurements• Remote sensing satellites provide global coverage each day• Day/night all weather• Atmosphere• Water vapor, cloud liquid water, precipitation• Sea Ice and land snow cover• Ocean• Surface winds, sea surface temperature
Kishore Kumar Parida EC200117313 [24]
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REFERENCES
[1] Lillesand Thomas M. and Ralph W. Kiefer,”Remote Sensing and Image Interpretation”, fourth edition, chapter 8,pp. 616-692
[2] Sullivan Roger J., “Radar Foundations for Imaging and Advanced Concepts”, Chapter 7, pp.191-194
[3] http://www.engr.ucf.edu/centers/cfrsl/[4] http://trmm.gsfc.nasa.gov/[5] Ulaby, F.T., R.K.Moore, and A.K.Fung, Microwave Remote
Sensing: Active and Passive, Addison-Welsey, Reading, MA; vol.1: Microwave Remote Sensing Fundamentals and Radiometry, 1981;vol. II: Radar Remote Sensing and Surface Scattering and Emission Theory, 1982;vol. III.
Kishore Kumar Parida EC200117313 [25]
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THANK YOU