Nagarjuna Radar Final

7/30/2019 Nagarjuna Radar Final

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WELCOME


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I WISHEVERYONE

A HAPPY ENGINEERS DAY


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RADAR

INANCIENT PERIOD


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Conceived as early as 1880 by HeinrichHertz

Observed that radio waves could be reflected offmetal objects.

Radio Aid to Detection And Ranging

1930s

Britain built the first ground-based early warningsystem called Chain Home.

1940

Invention of the magnetron permits high powertransmission at high frequency, thus makingairborne radar.
http://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/


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Following the First World War in which Acoustic detection had beenused against attacking aircraft in France experiments were carriedout across the South and South-East of Britains coasts.

The system was effective in principle and the large parabolic dishesfocussed the incoming parallel sound rays to a single point atwhich a listening device could be positioned. In calm air conditionsa range of about 15 miles (25 km) could be achieved but the speed(350 kph) of the aircraft in existence when the system was

eventually abandoned was such that only about 4 minutes warningof approach could be given.radio transmissions and direction sensing (see Dr Hans E Hollmann)through the work of scientists working with short wavelength radiodirection finders that the use of audio-detectors had little future.

However as an illustration of the rapid progress that can beexperienced in science and technology in only a decade the concretedishes and wheeled trolleys are a monument to ingenuity andinnovation in times of need despite their ultimate failure.
http://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.southdown-amateur-radio-society.org.uk/HTML/Soundmirrors.htmlhttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.google.co.uk/search?hl=en&defl=en&q=define:RADAR&sa=X&oi=glossary_definition&ct=titlehttp://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/http://www.ajg41.clara.co.uk/mirrors/


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This earlier version ( left ) from just after theFirst world war period - through to the Japanese version(above) showed that the thinking behind the technology

did not really changed. In fact the electronic device ofChristian Huelsmeyer had a far more scientific principleand clearly much greater potential than these. It ishardly surprising that RADAR developed as it did. By

early 1936 it was becoming clear that developments in anumber of sites give some detailed historic informationabout the development of the early sound detectionsystems and are well worth visiting and reading.
http://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htmhttp://www.design-technology.info/inventors/page28.htm


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We all know that a RADAR is used to

detect the position of aircraft usingradio waves. The term RADAR wasfirst coined in 1941 and stands for

dio etection nd anging. Beforethe invention of RADAR there wasobviously a need to detect enemyaircraft. So what do you think theydid? See pictures below
http://www.aviationearth.com/wp-content/uploads/2011/07/locator3.jpg


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http://www.aviationearth.com/wp-content/uploads/2011/07/locator9.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar14.jpg


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http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar14.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar05.jpg


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http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar04.jpg


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http://www.aviationearth.com/wp-content/uploads/2011/07/locator2.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar11.jpg


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http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar06.jpg


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RADARIN

MEDIEVAL PERIOD


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Currently Radar is the primary sensor on nearly all military

aircraft.

Roles include airborne early warning, target

acquisition, target tracking, target illumination,ground mapping, collision avoidance, altimeter,weather warning.

Practical frequency range of conventional RADAR is225MHz-35GHz.


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Two common transmission techniques: pulses

continuous wave


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Pulse Doppler Carrier wave frequency within pulse is compared with a

reference signal to detect moving targets.

Frequency Modulated CW Radar Use for radar altimeters and missile guidance.

Moving Target Indicator (MTI) System Signals compared with previous return to enhance moving

targets. (search radars)

Frequency Agile Systems Difficult to jam.


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SAR / ISAR Phased Array - Aegis

Essentially 360 Coverage

Phase shift and frequency shift allow the planar

array to steer the beam. Also allows for high / low power output depending

on requirements.


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Where :- fis the apparent frequency

vis velocity of wave in the medium vobsis the velocity of the receiver relative to themedium; positive if the receiver is movingtowards the source.

vsis the velocity of the source relative to themedium; positive if the source is moving awayfrom the receiver

fO is the frequency of wave


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Radar Frequencies


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Frequency

Wavelength 1 mm1 km 1 m 1 mm 1 nm

1 MHz 1 GHz

IR UV

109 Hz

0 1 2 3 4 5 6 7 8 9 10 11 12

30 20 10 8 6 5 4 39 7

Allocated Frequency (GHz)

Wavelength (cm)

X-BandC-BandS-BandL-BandUHF

VHF

Visible

1012 Hz

KuK

KaW


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A pulsed radar is characterized by a highpower transmitter that generates an endlesssequence of pulses. The rate at which thepulses are repeated is defined as the pulse

repetition frequency. Denote:

pulse width, , usually expressed in msec pulse repetition frequency, PRF, usually in kHz

pulse period, Tp = 1/PRF, usually in msec


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Power

Supply

SynchronizerTransmitter

Display

Duplexer

(Switching Unit)

Receiver

Antenna

Antenna Bearing or Elevation

Video

Echo

ATRRF

TR


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EEE381B


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2

*tcRange

c = 3 x 108 m/sec

t is time to receive return

divide by 2 because pulse traveled to object and back


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Atmospheric attenuation

Reflection off of earths

surface

Over-the-horizon

diffraction

Atmospheric refraction

Radar beams can be attenuated, reflected andbent by the environment


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A target whose range is: R Ramb = c / (2 PRF) = cTp / 2

0 10 20 30

PRF

Ramb

returntime


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A target whose range is : R Ramb = c / (2 PRF) = cTp / 2

0 10 20 30

PRF

Ramb

return time


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Which target is which?

0 10 20 30

PRF

Ramb

?


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The PRF is another key radar parameter andis arguably one of the most difficult designdecisions.

The range of a target becomes ambiguousas a function of half the pulse period; inother words targets that are further thanhalf the pulse period yield ambiguous range

results. Ramb = c / (2 PRF) = cTp / 2


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A basic principle of radar is that it directsenergy (in the form of an EM wave) at itsintended target(s).

Recall that the directivity of an antenna is

measured as a function of its gain. Therefore antenna types most useful for

radar applications include parabolic and arrayantenna.


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Early airborne radarstypically consisted ofparabolic reflectors with

horn feeds. The dish effectively directs

the transmitted energytowards a target while at thesame time gathering andconcentrating some fractionof the returned energy.


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Recent radars more likelyemploy a planar array It is electronically steerable

as a transmit or receiveantenna using phaseshifters.

It has the further advantageof being capable of being

integrated with the skin ofthe aircraft (smart skin).


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The main lobe of the radar antenna beam iscentral to the performance of the system. The side lobes are not only wasteful, they provide

electronic warfare vulnerabilities.


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Airborne radars are designed for and usedin many different modes. Common modesinclude: air-to-air search

air-to-air tracking air-to-air track-while-scan (TWS)

ground mapping

continuous wave (CW) illumination

multimode


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A target that is tracked is said to be lockedon; key data to maintain on locked targetsis: range, azimuth and elevation angle.

A frame of reference using pitch and rollfrom aircraft attitude indicators is requiredfor angle tracking. Three angle trackingtechniques are: sequential lobing conical scan monopulse


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synthetic-aperture radar (SAR): A coherentradar system that generates a narrow crossrange impulse response by signalprocessing (integrating) the amplitude andphase of the received signal over an angular

rotation of the radar line of sight withrespect to the object (target) illuminated.Note: Due to the change in line-of-sightdirection, a synthetic aperture is producedby the signal processing that has the effectof an antenna with a much larger aperture(and hence a much greater angularresolution). (IEEE standards)


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Video 1


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Final image with

lots of artifactsand features.

Step by step

analysis of theimage.


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Employs continualRADAR transmission

Separate transmitand receiveantennas

Relies on theDOPPLER SHIFT


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Motion Away:

Echo Frequency Decreases

Motion Towards:

Echo Frequency Increases


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Discriminator AMP Mixer

CW RFOscillator

Indicator

OUT

IN

Transmitter Antenna

Antenna


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Pulse Echo Single Antenna Gives Range,

usually Alt. as well Susceptible ToJamming

Physical RangeDetermined By PW

and PRF.

Continuous Wave Requires 2 Antennae Range or Alt. Info High SNR More Difficult to Jam

But Easily Deceived Amp can be tuned to

look for expectedfrequencies


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Amplitude Modulation Vary the amplitude of the carrier sine wave

Frequency Modulation

Vary the frequency of the carrier sine wave

Pulse-Amplitude Modulation

Vary the amplitude of the pulses

Pulse-Frequency Modulation

Vary the Frequency at which the pulses occur


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Azimuth Angular Measurement

Relative Bearing = Angle from ships heading.

True Bearing = Ships Heading + Relative Bearing

NShips Heading

Angle

Target Angle


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Determining Altitude

SlantR

ange

Altitude

Angle of Elevation

Altitude = slant range x sin0 elevation


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Signal Reception Receiver Bandwidth

Pulse Shape

Power Relation

Beam Width

Pulse RepetitionFrequency

Antenna Gain

Radar Cross Section of

Target

Signal-to-noise ratio Receiver Sensitivity

Pulse Compression

Scan Rate

Mechanical Electronic

Carrier Frequency

Antenna aperture


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Signal Reception Signal-to-Noise Ratio

Receiver Bandwidth

Receiver Sensitivity


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Only a minute portion of the

RF is reflected off the target. Only a fraction of that returns

to the antenna.

The weaker the signal thatthe receiver can process, thegreater the effective range .


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Measured in dB!!!!! Ability to recognize target in random noise.

Noise is always present.

At some range, noise is greater that targets

return. Noise sets the absolute lower limit of the

units sensitivity.

Threshold level used to remove excessnoise.


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Is the frequency range the receiver canprocess.

Receiver must process many frequencies Pulse are generated by summation of sine waves

of various frequencies. Frequency shifts occur from Doppler Effects.

Reducing the bandwidth Increases the signal-to-noise ratio(good)

Distorts the transmitted pulse(bad)


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Smallest return signal that is discernibleagainst the noise background. Milliwatts range.

An important factor in determining the units

maximum range.


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Mapping radar scans a large regions forremote sensing and geography applications

Wearable radar which is used to help thevisually impaired

Air traffic control uses radar to reflectechoes off ofaircraft

Weather radar uses radar to reflect echoesoff of clouds
http://www.mywiseowl.com/articles/Remote_sensinghttp://www.mywiseowl.com/articles/Geographyhttp://www.mywiseowl.com/articles/Remote_sensinghttp://www.mywiseowl.com/articles/Geographyhttp://www.wearcam.org/ece431/labs/lab3/lab3.htmhttp://www.mywiseowl.com/articles/Air_traffic_controlhttp://www.mywiseowl.com/articles/Aircrafthttp://www.mywiseowl.com/articles/Aircrafthttp://www.mywiseowl.com/articles/Aircrafthttp://www.mywiseowl.com/articles/Aircrafthttp://www.mywiseowl.com/articles/Air_traffic_controlhttp://www.wearcam.org/ece431/labs/lab3/lab3.htmhttp://www.mywiseowl.com/articles/Geographyhttp://www.mywiseowl.com/articles/Remote_sensing


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Search radars scan a large area with pulses of shortradio waves

Targeting radars use the same principle but scan asmaller area more often

Navigational radars are like search radar, but useshort waves that reflect off hard surfaces. They areused on commercial ships and long-distancecommercial aircraft


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Weather radars use radio waves with horizontal,dual (horizontal and vertical), or circularpolarization

Some weather radars use the Doppler effect to

measure wind speeds
http://localhost/var/www/apps/conversion/tmp/Doppler%20Effect/doppler.ppthttp://localhost/var/www/apps/conversion/tmp/Doppler%20Effect/doppler.ppt


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Used to study the Earth's ionosphere and itsinteractions with the upper atmosphere, themagnetosphere, and the solar wind
http://localhost/var/www/apps/conversion/tmp/scratch_1//hypatia/lmcgourty/The%20Atmosphere.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_1//hypatia/lmcgourty/The%20Atmosphere.ppt


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Electrons in ionosphere are radar targets

These electrons can scatter radio waves
http://www-lab26.kuee.kyoto-u.ac.jp/study/mu/mu_e.htmlhttp://en.wikipedia.org/wiki/Radiohttp://en.wikipedia.org/wiki/Radiohttp://www-lab26.kuee.kyoto-u.ac.jp/study/mu/mu_e.html


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The strength of the echo received from the

ionosphere measures the number of electronsable to scatter radio waves or what we call

electron pressure
http://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Pressure


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Some electrons aremoving due to heat - Inthis case the echo isscattered

The echo will contain arange offrequencies

close to the transmitterfrequency As the temperature

increases, the electronsmove faster

So radar can act like a

thermometer andmeasure thetemperature of theionosphere
http://www.energyinfonz.co.nz/home/KidsZone/Energybasics/HE.htmlhttp://www.energyinfonz.co.nz/home/KidsZone/Energybasics/HE.htmlhttp://www.glenbrook.k12.il.us/gbssci/phys/Class/waves/u10l2b.htmlhttp://www.glenbrook.k12.il.us/gbssci/phys/Class/waves/u10l2b.htmlhttp://www.glenbrook.k12.il.us/gbssci/phys/Class/waves/u10l2b.htmlhttp://www.energyinfonz.co.nz/home/KidsZone/Energybasics/HE.html


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When an electron is

removed from anatom, the remainingcharged atom is calledan ion

The ion gas can have a

different temperaturefrom the electron gas The electron/ion

mixture is known as aplasma and is usuallyin motion (like ourwind)

So incoherent scatterradar can also measurewind speed
http://www.chem4kids.com/files/atom_ions.htmlhttp://www.chem4kids.com/files/atom_ions.htmlhttp://www.chem4kids.com/files/matter_plasma.htmlhttp://www.chem4kids.com/files/matter_plasma.htmlhttp://www.chem4kids.com/files/matter_plasma.htmlhttp://www.chem4kids.com/files/atom_ions.html


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To prevent maritime accidents in congested waters and


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To prevent maritime accidents in congested waters and

improve the efficiency of vessel traffic, it is important to

know the vessel traffic characteristics and carry out

appropriate vessel traffic management.

Up to now, vessel traffic observation has needed

expensive resources such as a ship or car equipped withspecial radar observation system and experienced

observation staff.

In order to perform long-term and long-range vessel

traffic observations in Tokyo Bay, completely automated

remote radar/AIS network system has been developed.


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MonitoringStation

Kawasaki Radar

Station

Yokosuka RadarStation

Tokyo University ofMarine Science and

Technology


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Radar antenna at Yokosuka

radar stationRadar antenna and AIS receiver at

Kawasaki radar station


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Composite radar image from Yokosuka and Kawasaki

radar stations displayed on the monitoring screen


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Composite radar image and ships positions and

speed vectors obtained from AIS on web site


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AIS information display on web site


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Named WSR-88D S-band radar

radiationwavelength is =

10.7 cm Power is 750,000

kW

Tallahassee (right)


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Radio Detection and Ranging When the electromagnetic pulse hits something,

some of it bounces back

Can determine where the particle was

Measures reflectivity of the particle

NEXRAD can also detect motion of the particles(Doppler effect)


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Ima e courtes


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Ima e courtes

=Size( +)=Shape( +)=Variety

Dual-Polarization Radartells us about the size,

shape, & variety of objects.


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NEXRAD Doppler Radar Network


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NEXRAD Facts and Figures


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158 radars (141 in the Continental US) 120 National Weather Service radars 26 Department of Defense radars 12 Federal Aviation Administration radars

NEXRAD Data Types


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Archive Level I (raw receiver data) Level II data (digital data in spherical

coordinates at full resolution) Archive Level III (digital products) Archive Level IV (forecaster-generated

products)

NEXRAD Data Types


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Archive Level I (raw receiver data) Level II data (digital data in spherical

coordinates at full resolution) Archive Level III (digital products) Archive Level IV (forecaster-generated

products)


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s fn

24 products available from all CONUSradars in real time

Lowest 4 elevation angles only

Low-precision because values are

quantized (e.g., 0-5, 5-10, 10-15)


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dBZ levelshigher than30 (dark

green) arerainfallreachingthe ground.Thoseabove 65(purple) arelikely hail.

dBZ values


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dBZ valuesbelow 30

becomeimportantnow.

If rain and

Documents

Nagarjuna Radar Final