Nagarjuna Radar Final
-
Upload
malakonda-reddy -
Category
Documents
-
view
227 -
download
0
Transcript of Nagarjuna Radar Final
-
7/30/2019 Nagarjuna Radar Final
1/131
-
7/30/2019 Nagarjuna Radar Final
2/131
-
7/30/2019 Nagarjuna Radar Final
3/131
WELCOME
-
7/30/2019 Nagarjuna Radar Final
4/131
I WISHEVERYONE
A HAPPY ENGINEERS DAY
-
7/30/2019 Nagarjuna Radar Final
5/131
-
7/30/2019 Nagarjuna Radar Final
6/131
-
7/30/2019 Nagarjuna Radar Final
7/131
RADAR
INANCIENT PERIOD
-
7/30/2019 Nagarjuna Radar Final
8/131
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/ -
7/30/2019 Nagarjuna Radar Final
9/131
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/ -
7/30/2019 Nagarjuna Radar Final
10/131
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 -
7/30/2019 Nagarjuna Radar Final
11/131
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 -
7/30/2019 Nagarjuna Radar Final
12/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator3.jpg -
7/30/2019 Nagarjuna Radar Final
13/131
-
7/30/2019 Nagarjuna Radar Final
14/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator10.jpg -
7/30/2019 Nagarjuna Radar Final
15/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator10.jpg -
7/30/2019 Nagarjuna Radar Final
16/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator9.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar14.jpg -
7/30/2019 Nagarjuna Radar Final
17/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar14.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar05.jpg -
7/30/2019 Nagarjuna Radar Final
18/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar05.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar04.jpg -
7/30/2019 Nagarjuna Radar Final
19/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar04.jpg -
7/30/2019 Nagarjuna Radar Final
20/131
-
7/30/2019 Nagarjuna Radar Final
21/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator14.jpg -
7/30/2019 Nagarjuna Radar Final
22/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator14.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/locator8.jpg -
7/30/2019 Nagarjuna Radar Final
23/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator8.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/locator16.jpg -
7/30/2019 Nagarjuna Radar Final
24/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator16.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/locator12.jpg -
7/30/2019 Nagarjuna Radar Final
25/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator12.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/locator2.jpg -
7/30/2019 Nagarjuna Radar Final
26/131
http://www.aviationearth.com/wp-content/uploads/2011/07/locator2.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar11.jpg -
7/30/2019 Nagarjuna Radar Final
27/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar11.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar10.jpg -
7/30/2019 Nagarjuna Radar Final
28/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar10.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar07.jpg -
7/30/2019 Nagarjuna Radar Final
29/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar07.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar08.jpg -
7/30/2019 Nagarjuna Radar Final
30/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar08.jpghttp://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar06.jpg -
7/30/2019 Nagarjuna Radar Final
31/131
http://www.aviationearth.com/wp-content/uploads/2011/07/aircraftdetectionbeforeradar06.jpg -
7/30/2019 Nagarjuna Radar Final
32/131
-
7/30/2019 Nagarjuna Radar Final
33/131
-
7/30/2019 Nagarjuna Radar Final
34/131
RADARIN
MEDIEVAL PERIOD
-
7/30/2019 Nagarjuna Radar Final
35/131
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.
-
7/30/2019 Nagarjuna Radar Final
36/131
-
7/30/2019 Nagarjuna Radar Final
37/131
Two common transmission techniques: pulses
continuous wave
-
7/30/2019 Nagarjuna Radar Final
38/131
-
7/30/2019 Nagarjuna Radar Final
39/131
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.
-
7/30/2019 Nagarjuna Radar Final
40/131
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.
-
7/30/2019 Nagarjuna Radar Final
41/131
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
-
7/30/2019 Nagarjuna Radar Final
42/131
Radar Frequencies
-
7/30/2019 Nagarjuna Radar Final
43/131
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
-
7/30/2019 Nagarjuna Radar Final
44/131
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
-
7/30/2019 Nagarjuna Radar Final
45/131
Power
Supply
SynchronizerTransmitter
Display
Duplexer
(Switching Unit)
Receiver
Antenna
Antenna Bearing or Elevation
Video
Echo
ATRRF
TR
-
7/30/2019 Nagarjuna Radar Final
46/131
EEE381B
-
7/30/2019 Nagarjuna Radar Final
47/131
-
7/30/2019 Nagarjuna Radar Final
48/131
2
*tcRange
c = 3 x 108 m/sec
t is time to receive return
divide by 2 because pulse traveled to object and back
-
7/30/2019 Nagarjuna Radar Final
49/131
-
7/30/2019 Nagarjuna Radar Final
50/131
Atmospheric attenuation
Reflection off of earths
surface
Over-the-horizon
diffraction
Atmospheric refraction
Radar beams can be attenuated, reflected andbent by the environment
-
7/30/2019 Nagarjuna Radar Final
51/131
-
7/30/2019 Nagarjuna Radar Final
52/131
-
7/30/2019 Nagarjuna Radar Final
53/131
-
7/30/2019 Nagarjuna Radar Final
54/131
A target whose range is: R Ramb = c / (2 PRF) = cTp / 2
0 10 20 30
PRF
Ramb
returntime
-
7/30/2019 Nagarjuna Radar Final
55/131
A target whose range is : R Ramb = c / (2 PRF) = cTp / 2
0 10 20 30
PRF
Ramb
return time
-
7/30/2019 Nagarjuna Radar Final
56/131
Which target is which?
0 10 20 30
PRF
Ramb
?
-
7/30/2019 Nagarjuna Radar Final
57/131
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
-
7/30/2019 Nagarjuna Radar Final
58/131
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.
-
7/30/2019 Nagarjuna Radar Final
59/131
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.
-
7/30/2019 Nagarjuna Radar Final
60/131
-
7/30/2019 Nagarjuna Radar Final
61/131
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).
-
7/30/2019 Nagarjuna Radar Final
62/131
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.
-
7/30/2019 Nagarjuna Radar Final
63/131
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
-
7/30/2019 Nagarjuna Radar Final
64/131
-
7/30/2019 Nagarjuna Radar Final
65/131
-
7/30/2019 Nagarjuna Radar Final
66/131
-
7/30/2019 Nagarjuna Radar Final
67/131
-
7/30/2019 Nagarjuna Radar Final
68/131
-
7/30/2019 Nagarjuna Radar Final
69/131
-
7/30/2019 Nagarjuna Radar Final
70/131
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
-
7/30/2019 Nagarjuna Radar Final
71/131
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)
-
7/30/2019 Nagarjuna Radar Final
72/131
-
7/30/2019 Nagarjuna Radar Final
73/131
Video 1
-
7/30/2019 Nagarjuna Radar Final
74/131
-
7/30/2019 Nagarjuna Radar Final
75/131
Final image with
lots of artifactsand features.
Step by step
analysis of theimage.
-
7/30/2019 Nagarjuna Radar Final
76/131
-
7/30/2019 Nagarjuna Radar Final
77/131
Employs continualRADAR transmission
Separate transmitand receiveantennas
Relies on theDOPPLER SHIFT
-
7/30/2019 Nagarjuna Radar Final
78/131
Motion Away:
Echo Frequency Decreases
Motion Towards:
Echo Frequency Increases
-
7/30/2019 Nagarjuna Radar Final
79/131
Discriminator AMP Mixer
CW RFOscillator
Indicator
OUT
IN
Transmitter Antenna
Antenna
-
7/30/2019 Nagarjuna Radar Final
80/131
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
-
7/30/2019 Nagarjuna Radar Final
81/131
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
-
7/30/2019 Nagarjuna Radar Final
82/131
-
7/30/2019 Nagarjuna Radar Final
83/131
Azimuth Angular Measurement
Relative Bearing = Angle from ships heading.
True Bearing = Ships Heading + Relative Bearing
NShips Heading
Angle
Target Angle
-
7/30/2019 Nagarjuna Radar Final
84/131
Determining Altitude
SlantR
ange
Altitude
Angle of Elevation
Altitude = slant range x sin0 elevation
-
7/30/2019 Nagarjuna Radar Final
85/131
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
-
7/30/2019 Nagarjuna Radar Final
86/131
Signal Reception Signal-to-Noise Ratio
Receiver Bandwidth
Receiver Sensitivity
-
7/30/2019 Nagarjuna Radar Final
87/131
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 .
-
7/30/2019 Nagarjuna Radar Final
88/131
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.
-
7/30/2019 Nagarjuna Radar Final
89/131
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)
-
7/30/2019 Nagarjuna Radar Final
90/131
Smallest return signal that is discernibleagainst the noise background. Milliwatts range.
An important factor in determining the units
maximum range.
-
7/30/2019 Nagarjuna Radar Final
91/131
-
7/30/2019 Nagarjuna Radar Final
92/131
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 -
7/30/2019 Nagarjuna Radar Final
93/131
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
-
7/30/2019 Nagarjuna Radar Final
94/131
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 -
7/30/2019 Nagarjuna Radar Final
95/131
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 -
7/30/2019 Nagarjuna Radar Final
96/131
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 -
7/30/2019 Nagarjuna Radar Final
97/131
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 -
7/30/2019 Nagarjuna Radar Final
98/131
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 -
7/30/2019 Nagarjuna Radar Final
99/131
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 -
7/30/2019 Nagarjuna Radar Final
100/131
To prevent maritime accidents in congested waters and
-
7/30/2019 Nagarjuna Radar Final
101/131
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.
-
7/30/2019 Nagarjuna Radar Final
102/131
MonitoringStation
Kawasaki Radar
Station
Yokosuka RadarStation
Tokyo University ofMarine Science and
Technology
-
7/30/2019 Nagarjuna Radar Final
103/131
Radar antenna at Yokosuka
radar stationRadar antenna and AIS receiver at
Kawasaki radar station
-
7/30/2019 Nagarjuna Radar Final
104/131
Composite radar image from Yokosuka and Kawasaki
radar stations displayed on the monitoring screen
-
7/30/2019 Nagarjuna Radar Final
105/131
Composite radar image and ships positions and
speed vectors obtained from AIS on web site
-
7/30/2019 Nagarjuna Radar Final
106/131
AIS information display on web site
-
7/30/2019 Nagarjuna Radar Final
107/131
-
7/30/2019 Nagarjuna Radar Final
108/131
Named WSR-88D S-band radar
radiationwavelength is =
10.7 cm Power is 750,000
kW
Tallahassee (right)
-
7/30/2019 Nagarjuna Radar Final
109/131
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)
-
7/30/2019 Nagarjuna Radar Final
110/131
-
7/30/2019 Nagarjuna Radar Final
111/131
-
7/30/2019 Nagarjuna Radar Final
112/131
-
7/30/2019 Nagarjuna Radar Final
113/131
Ima e courtes
-
7/30/2019 Nagarjuna Radar Final
114/131
Ima e courtes
=Size( +)=Shape( +)=Variety
Dual-Polarization Radartells us about the size,
shape, & variety of objects.
-
7/30/2019 Nagarjuna Radar Final
115/131
-
7/30/2019 Nagarjuna Radar Final
116/131
NEXRAD Doppler Radar Network
-
7/30/2019 Nagarjuna Radar Final
117/131
NEXRAD Facts and Figures
-
7/30/2019 Nagarjuna Radar Final
118/131
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
-
7/30/2019 Nagarjuna Radar Final
119/131
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
-
7/30/2019 Nagarjuna Radar Final
120/131
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)
-
7/30/2019 Nagarjuna Radar Final
121/131
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)
-
7/30/2019 Nagarjuna Radar Final
122/131
-
7/30/2019 Nagarjuna Radar Final
123/131
-
7/30/2019 Nagarjuna Radar Final
124/131
dBZ levelshigher than30 (dark
green) arerainfallreachingthe ground.Thoseabove 65(purple) arelikely hail.
dBZ values
-
7/30/2019 Nagarjuna Radar Final
125/131
dBZ valuesbelow 30
becomeimportantnow.
If rain and