SEMINAR ON SEMINAR ON MICROWAVE REMOTE MICROWAVE REMOTE

SENSINGSENSING

SUBMITTED TOSUBMITTED TO

DR.C.J.KUMANAN,DR.C.J.KUMANAN,

LECTURER.LECTURER.

CERS.CERS.

SUBMITTED BY,SUBMITTED BY,

P.AMALADAS,P.AMALADAS,

I M.Sc.I M.Sc.

GEOINFORMAICS.GEOINFORMAICS.

MICROWAVE REMOTE MICROWAVE REMOTE SENSINGSENSING

INTRODUCTIONINTRODUCTION MICROWAVEREMOTESENSING TECHNICQUE MICROWAVEREMOTESENSING TECHNICQUE

IS A IS A RELATIVELY NEW FIELD COMPARED TO THERELATIVELY NEW FIELD COMPARED TO THE VISIBLE AND INFRA_RED REGION OF THEVISIBLE AND INFRA_RED REGION OF THE ELECTROMAGNECTIC SPECTURM .ELECTROMAGNECTIC SPECTURM .

MICROWAVE SENSOR MAKE USE OF THE MICROWAVE SENSOR MAKE USE OF THE FREQUNCY RANGE FROM ABOUT 1 TO 300 FREQUNCY RANGE FROM ABOUT 1 TO 300 GHZ OF SPECTRUM GHZ OF SPECTRUM

BASIC PRINCPLESBASIC PRINCPLES

ELECTROMAGNETIC ENERGY INCIDENT ELECTROMAGNETIC ENERGY INCIDENT ON OBJECT UNDERGOES SEVERAL ON OBJECT UNDERGOES SEVERAL TRANSFORMATION. BY VIRTUE OF THE TRANSFORMATION. BY VIRTUE OF THE PROPERTICE OF THE TARGET,THE PROPERTICE OF THE TARGET,THE SIGNAL MAY UNDERGO SIGNAL MAY UNDERGO

REFLECTION,REFRACTION SCATTRING REFLECTION,REFRACTION SCATTRING OBSORBTION,DIFFRACTION. OBSORBTION,DIFFRACTION.

RADIOMETERRADIOMETER

THE BASIC PHYSICAL PRINCIPLE OF THE BASIC PHYSICAL PRINCIPLE OF EMISSION FROM TARGET PLAYS EMISSION FROM TARGET PLAYS MAJOR ROLE IN THE UNDERSTANDING MAJOR ROLE IN THE UNDERSTANDING AND DESIGN OF A MICROWAVE AND DESIGN OF A MICROWAVE RADIOMETER.RADIOMETER.

THESE ARE BASICALY THESE ARE BASICALY CLASSIFIED AS TWO SENSORSCLASSIFIED AS TWO SENSORS

ACTIVE SENSOR ACTIVE SENSOR PASSIVE SENSORPASSIVE SENSOR

ACTIVE SENSORACTIVE SENSORACTIVE SENSOR CONSISTS OF A ACTIVE SENSOR CONSISTS OF A TRANMITTER AND RECIVER .IN ACUAL TRANMITTER AND RECIVER .IN ACUAL FIELD APPLICATION,THE TRANSMITTED FIELD APPLICATION,THE TRANSMITTED ENERGE REFLECTED AND OR SCATTERED ENERGE REFLECTED AND OR SCATTERED FROM THE TARGETFROM THE TARGET

EXAMPLEEXAMPLE

SLAR,SAR,SCATTREROMETER,SLAR,SAR,SCATTREROMETER,

AND ALTIMETERAND ALTIMETER

SIDE LOOKING AREBORNE SIDE LOOKING AREBORNE RADARRADAR

A A VERTICALY DOWNWARD LOOKING RADAR VERTICALY DOWNWARD LOOKING RADAR RECEIVES SIGNALS FROM A CIRCULAR RECEIVES SIGNALS FROM A CIRCULAR PATCH OF AREA ILLUMINATED BY THE PATCH OF AREA ILLUMINATED BY THE ANTENNA. ANTENNA.

THE SIGNALS SCATTERED / REFLECTED THE SIGNALS SCATTERED / REFLECTED FROM ALL THE ELEMENTAL AREAS LYING FROM ALL THE ELEMENTAL AREAS LYING ON THE CIRCUMFERENCE OF THE CIRCLE ON THE CIRCUMFERENCE OF THE CIRCLE ARRIVE AT THE SAME INSTANT SINCE THE ARRIVE AT THE SAME INSTANT SINCE THE TIME ELAPSED FOR THE TWO-WAYS SIGNAL TIME ELAPSED FOR THE TWO-WAYS SIGNAL PROPAGATION IS THE SAME FOR ALL SUCH PROPAGATION IS THE SAME FOR ALL SUCH POINTS POINTS

SYNTHETIC APERTURE SYNTHETIC APERTURE RADAR(SAR)RADAR(SAR)

IN SYNTHETIC APERTURE RADAR IN SYNTHETIC APERTURE RADAR IMAGING MICROWAVE PULSES ARE IMAGING MICROWAVE PULSES ARE TRANSMITTED BY AN ANTENNA TRANSMITTED BY AN ANTENNA TOWARDS THE EARTH SURFACE.TOWARDS THE EARTH SURFACE.

MICROWAVE ENERGY SCARTTERED MICROWAVE ENERGY SCARTTERED BACK TO THE SPACECRAFT IS BACK TO THE SPACECRAFT IS MEASURED. MEASURED.

SCATTEROMETERSCATTEROMETER

A SCATTEROMETER IS A RADAR A SCATTEROMETER IS A RADAR WHICH MEASURE THE SCATTERING WHICH MEASURE THE SCATTERING COEFFICENT,SIGMA,OF A TARGET IS COEFFICENT,SIGMA,OF A TARGET IS NOMALLY USED IN FIELD UNDER NOMALLY USED IN FIELD UNDER CONTROLLED ENVIROMENT TO STUDY CONTROLLED ENVIROMENT TO STUDY THE SACATTERING PROPERTIES OF A THE SACATTERING PROPERTIES OF A WELL-DIFINED OBJECTS.WELL-DIFINED OBJECTS.

ALTIMETERALTIMETER

ALTIMETER IS A STRAIGHT FORWARD ALTIMETER IS A STRAIGHT FORWARD RADAR WERE THE DELAY IN THE TWO RADAR WERE THE DELAY IN THE TWO WAYS PROPAGATION OF THE WAYS PROPAGATION OF THE TRANSMITTED PULSES DETERMINE TRANSMITTED PULSES DETERMINE THE DISTANCE /THE DISTANCE /

PASSIVE SENSORPASSIVE SENSOR

PASSIVE SENSOR CONSISTS OF ONLY A PASSIVE SENSOR CONSISTS OF ONLY A RECIVER. EMITTED RADIATION FROM RECIVER. EMITTED RADIATION FROM MANMADE OR NATURAL TARGET IS MANMADE OR NATURAL TARGET IS RECIVED AND PROCESSED BY THE RECIVED AND PROCESSED BY THE RADIOMETER TO INFER THE TARGET RADIOMETER TO INFER THE TARGET PROPERTIES.PROPERTIES.

EXAMPLE:EXAMPLE: SCANNER,SCANNER, TOTAL POWER RADIOMETER,TOTAL POWER RADIOMETER, DICKE RADIOMETER.DICKE RADIOMETER.

SCANNERSCANNER

THE SCANNER IS TWO TYPES THE SCANNER IS TWO TYPES

1.PUSHBROOM (ALONG TRACK)1.PUSHBROOM (ALONG TRACK)

2.WISHBROOM (ACROSS TRACK)2.WISHBROOM (ACROSS TRACK)

TOTAL POWER RADIOMETERTOTAL POWER RADIOMETER

THE BASIC RADIOMETER IS A SIMPLE THE BASIC RADIOMETER IS A SIMPLE STRAIGHT FORWARD RECIVER WITH STRAIGHT FORWARD RECIVER WITH AN ANTENNA. BECAUSE OF THE AN ANTENNA. BECAUSE OF THE RANDOM NATURE OF THE RANDOM NATURE OF THE ORGINATING SIGNAL.ORGINATING SIGNAL.

DICKE RADIOMETERDICKE RADIOMETER ONE OF THE DRAWBACKS OF THE TPR ONE OF THE DRAWBACKS OF THE TPR

IS THE INHERENT GAIN FLUTUATION IS THE INHERENT GAIN FLUTUATION OF THE RECEIVER WHICH AFFECT THE OF THE RECEIVER WHICH AFFECT THE SENSITIVITY OF THE RADIOMETER. SENSITIVITY OF THE RADIOMETER.

ΔΔT(rms)=2(Tb+Trec)/√(BT)T(rms)=2(Tb+Trec)/√(BT)

DICKE RADIOMETER

RADARRADAR

THE WORD RADAR IS AN ACRONYM THE WORD RADAR IS AN ACRONYM FOR RADIO DETECTION AND RANGE.AS FOR RADIO DETECTION AND RANGE.AS ITS NAME IMPLIES RADAR WAS ITS NAME IMPLIES RADAR WAS DEVELOPED AS A MEAN OF USING DEVELOPED AS A MEAN OF USING RADIO WAVES TO DETECT THE RADIO WAVES TO DETECT THE PRECENCE OF OBJECTS AND PRECENCE OF OBJECTS AND DETERMINE THE RANGEDETERMINE THE RANGE

RADAR FREQUENCY RADAR FREQUENCY DESIGNATIONSDESIGNATIONS

BAND WAVELENGTH FREQUENCYBAND WAVELENGTH FREQUENCY P 107-77cm 300-1000P 107-77cm 300-1000 L 30-15cm 1000-2000L 30-15cm 1000-2000 S 15-7.5cm 2000-4000S 15-7.5cm 2000-4000 C 7.5-3.75cm 4000-8000C 7.5-3.75cm 4000-8000 X 3.75-2.40cm 8000-12000X 3.75-2.40cm 8000-12000 Ku 2.40-1.67cm 12000-18000Ku 2.40-1.67cm 12000-18000 K 1.670-1.18cm 18000-27000K 1.670-1.18cm 18000-27000 Ka 1.18-0.75cm 27000-40000 Ka 1.18-0.75cm 27000-40000

SURFACE ROUGHNESSSURFACE ROUGHNESS

IT IS A FUNCTION OF THE INCIDENT IT IS A FUNCTION OF THE INCIDENT ANGLE WAVELENGTH.ANGLE WAVELENGTH.

RAYLEIGHS LAW:RAYLEIGHS LAW:

h<h<λλ/8cos/8cosθθ

where h- height variation where h- height variation

θθ – incident angle – incident angle

TYPESTYPES

SLIGHTLY ROUGH SURACESLIGHTLY ROUGH SURACE SMOOTH UNDULATING SURFACE SMOOTH UNDULATING SURFACE VERY ROUGH SURFACEVERY ROUGH SURFACE

SLIGHTLY ROUGH SURFACESLIGHTLY ROUGH SURFACE

THE HEIGHT VARIATION ARE THE HEIGHT VARIATION ARE SMALL COMPARE WITH THE SMALL COMPARE WITH THE WAVELENGTH AND THE SURFACE WAVELENGTH AND THE SURFACE SLOPES ARE SMALL COMPARED WITH SLOPES ARE SMALL COMPARED WITH UNITY.UNITY.

SMOOTH UNDULATING SMOOTH UNDULATING SURFACESURFACE

THE HEIGHT VARIATION THE HEIGHT VARIATION ARE COMPARABLE TO OR LAGRER ARE COMPARABLE TO OR LAGRER THAN THE WAVELENGH AND THE THAN THE WAVELENGH AND THE SUFACE IS LOCALY FLAT RELATIVE TO SUFACE IS LOCALY FLAT RELATIVE TO THE WAVELENGTH.THE WAVELENGTH.

VERY ROUGH SURFACEVERY ROUGH SURFACE

A LARGE SCALE ROUGHNESS A LARGE SCALE ROUGHNESS SATISFYING THE TARGET PLANE SATISFYING THE TARGET PLANE APPROXIMATION SUPERIMPOSED BY A APPROXIMATION SUPERIMPOSED BY A SMALL SCALE ROUGHNESS. SMALL SCALE ROUGHNESS.

EXAMPLE: SEA SURFACE WITH LARGE EXAMPLE: SEA SURFACE WITH LARGE GRAVITY GRAVITY

LIDARLIDAR

THE FINAL RADAR LIGHT SYSTEM WE WISH THE FINAL RADAR LIGHT SYSTEM WE WISH TO MENTION IN CLOSING. THIS IS LIDAR TO MENTION IN CLOSING. THIS IS LIDAR STAND FOR “ LIGHT DETECTION AND STAND FOR “ LIGHT DETECTION AND RANGING” RANGING”

AS WITH RADAR ,LIDAR SYSTEM ARE AS WITH RADAR ,LIDAR SYSTEM ARE ACTIVE REMOTE SENCING SYSTEM.ACTIVE REMOTE SENCING SYSTEM.

THEY SIMPLY USE PULSES OF LASER, THEY SIMPLY USE PULSES OF LASER, RATHER THAN MICROWAVE ENERGY TO RATHER THAN MICROWAVE ENERGY TO ILLUMINATE THE TERRAIN.ILLUMINATE THE TERRAIN.

EXAMPLE: VEGETATION AND SEA SURFACEEXAMPLE: VEGETATION AND SEA SURFACE

THANK U