All info about DWR and its full features

Doppler Weather
Radar
VISAKHAPATNAM
www.imd.gov.in
G.SRINIVASARAO
METEOROLOGIST

IMD MANDATE
 National Meteorological service of
 the country
 Principal Government Agency to
Meteorology and allied subjects
 Take Meteorological observations
and issue WX Forecast to WX
sensitive agencies.
 Severe WX Warnings
 Conduct and promote Research in
Meteorology and allied subjects

RADAR
RADAR
 RADAR IS A CONTRACTION OF THE WORDS RADIO
 DETECTION AND RANGING.
 A DEVICE TO DETECT THE PRESENCE OF A TARGET AND
 TO MEASURE ITS RANGE.
 SENDS ELECTROMAGNETIC WAVES INTO SPACE AND
 DETECTS THE ECHO SIGNAL REFLECTED FROM AN
 OBJECT.
 RADARS OPERATE AT THE MICROWAVE FREQUENCIES
DEPENDING UPON THE REQUIREMENT.

 CONVENTIONAL WEATHER RADARS
 DOPPLER WEATHER RADARS
 POLARIMETRIC DOPPLER WEATHER
RADARS

RADAR FREQUENCY BANDS
RADAR FREQUENCY BANDS
BAND NAME FREQUENCY RANGE IN GHz
S 2.0 – 4.0
C 4.0 – 8.0
X 8.0 – 12.0

DOPPLER WEATHER RADAR OF
VISAKHAPATNAM
MAKE: M/S GEMATRONIK GmbH, GERMANY
MODEL: METEOR 1500SLP10
YEAR OF INSTALLATION: 2006
PURPOSE: DETECTION & TRACKING OF CYCLONES
OUT IN THE SEA, NOWCASTING
RANGE: UP TO 500 KM FOR REFLECTIVITY
UPTO 250 KM FOR VELOCITY

Whenever there is a relative motion between
a source and observer, the frequency observed
by observer is different from the frequency
produced by source. If source is moving towards
the observer, the frequency increases and if
source is moving away from the observer,
frequency observed by the observer decreases.
The shift in the frequency is proportional to the
relative velocity of source
Doppler Effect

SPECIFICATIONS : GENERAL
 FREQUENCY : 2870 MHz (S Band)
 TRANSMITTER PEAK RF POWER OUTPUT : 750 KW
 TRANSMITTER OUTPUT STAGE : KLYSTRON (6 CAVITY)
 DESIGN : MODULAR
 RECEIVER : ANALOG AT FRONT END
 DIGITAL AFTER FIRST IF
 RECEIVER MDDS : -114 dBm AT LNA INPUT
 RECEIVER DYNAMIC RANGE : 95 dB
 ANTENNA : 8.5 MTR DIA PARABOLIC SOLID DISH. LIN HOR POLARISED,
1 Deg Beam Width, 45 dB Gain, 0.5 TO 6 RPM
 RADOME : 11.6 MTR DIA SANDWITCHED FIBRE GLASS, WHITE COLOR,
QUASI RANDOOM PANELS, 0.1 dB ONE WAY ATTN
 DISPLAY: WINDOWS BASED PC REAL TIME DISPLAY USIG “RAVIS” SOFTWARE
 PRODUCT GENERATION : SUN SOLARIS WORKSTATION USING “RAINBOW”
SOFTWARE
 FEATURES: DIGITAL SIGNAL PROCESSING, DIGITAL RADAR CONTROL, REMOTE
MAINTENANCE AND CONTROL USING TCP/IP, BUILT IN TEST EXQUIPMENT, LAN
CONNECTIVITY, CLUTTER SUPPRESSION, RANGE NORMALIZATION ETC

TRANSMITTER ROOM
TRANSMITTER ROOM

MAIN POWER SUPPLY
 THE MODULATOR IS SUPPLIED WITH
CONSTANT DC BY THE MPS
POWER(OUT PUT 1000VDC) WHICH
CHARGES THE PULSE CAPACITORS OF
THE SWITCH BOARDS.

ACTIVE SWITCH MODULATOR
 IT CONSISTS OF 6 SWITCH BOARDS
AND 1 SWICH ARRAY CONTROL
BOARD. THE BANK OF PULSE
CAPACITORS IN SWITCH BOARDS ARE
USED AS ENERGY STORAGE DEVICE,
WHICH IS DISCHARGED BY AN
INSULATED GATE BIPOLAR
TRANSISSTOR(IGBT) INTO PULSE
TRANSFORMER. THE PULSE WIDTH IS
CONTROLLED BY THE TIME BETWEEN
THE IGBT IS SWITCHED ON AND OFF.

SWITH BOARD
 IT CONSISTS
OF PULSE
CAPACITORS
AND 4 IGBT
SWITCHES
CONNECTED IN
PARALLEL.THE
SWITCHES ARE
TRIGGERED BY
THE RADAR
SIGNAL
PROCESSOR
VIA THE
SWITCH ARRAY
CONTROL
BOARD.

SWITCH ARRAY CONTROL BOARD
 SWITCH ARRAY
CONTROL BOARD
PROVIDES THE
TRIGGER PULSE
FOR THE S.Bs
AND MONITOR
THE CRITICIAL
PARAMETERS OF
THE S.Bs.

FILMENT POWER SUPPLY
 IT PROVIDES THE HEATING POWER
FOR THE FILAMENT OF THE
KLYSTRON.

BIAS POWER SUPPLY
 IT PROVIDES
THE HIGH
CURRENT
 REQUIRED FOR
THE PRE-
MAGNETISATIO
N OF THE
PULSE
TRANSFORMER.

SOLENOID POWER SUPPLY
 Solenoid power
supply is used
to give the
input supply
voltage to
Solenoid
(Electro
Magnet for
Klystron)

BOOSTER AMPLIFIER
 IT PROVIDES
THE POWER
LEVEL WHICH
IS REQUIRED
TO DRIVE THE
KLYSTRON.

KLYSTRON
 The Klystron
(41Kgs) is a high
power linear
beam microwave
tube amplifier
which provides
the microwave
pulse power
required for the
Radar system

SOLENOID
 The Solenoid
(160 Kgs) is a
high power
electromagnet
which focuses
the electron
beam in the
drift section of
the klystron

KLYSTRON TANK
1. PULSE
TRANSFORMER
2. FILMENT ISOATION
TRANSFORMER
3. BIOS CHOKE
4. THE PEAK
CURRENT
MONITOR BOARD
5. FOR ISOLATION
PURPOSE IT IS
FILLED WITH
TRANSFORMER
OIL

BASE FOR FILMENT
TRANSFORMER OIL

RECEIVER PARTS
 1. DOWN CONVERTER: USED TO
DOWNCONVERTING THE RECEIVED SIGNAL TO FIRST
IF 460 MHZ AND AGAIN DOWNCONVERTING TO
SECOND I.F 10MHZ.
 2. STALO UNIT: HIGH STABILITY AND LOWEST
PHASE NOISE. PRODUCE FREQUENCY OF 2400 MHZ.
 3. 2ND
L.O UNIT: PRODUCE FREQUENCY OF 460MHZ.
 4. TX CHANNEL: VIA THE TX CHANNEL THE
TRANSMITTERD PULSE ENTERS THE RECEIVER.
 5. POWER AMPLIFIER: TO AMPLIFY THE LOW LEVEL
SIGNAL FROM UP CONVERTER TO A HIGH LEVEL
WHICH IS NECESSARY TO DRIVE THE KLYSTRON.

DIGITAL RECEIVER
 ALL THE ANALOGUE AND DIGITAL
INTERFACES BETWEEN THE RADAR
AND EXTERNAL RCP IS PROVIDED
BY THE DIGITAL RECEIVER(DRX).

RADAR SIGNAL PROCESSOR
 TIMING OF ALL EVENTS IS A VERY
IMPORTANT FUNCTION IN A RADAR
SYSTEM. THEREFORE THE PROCESSES
IN THE ANTENNA, THE TX, THE RX
NEED TO BE SYNCHRONISED, WHICH
IS CONTROLLED BY THE RSP. THE RSP
SENDS TIMED SIGNALS OR TRIGGERS
TO THE VARIOUS COMPONENTS

LOCAL CONTROL UNIT
 Radar system can be
controlled by the user
through 3 types of control
devices
 1. LCU, highest control
level.
 2. Radar Visualization
Software (Ravis): This is a
Java-based software
package for general radar
control.
 3. Rainbow: The Unix-based
software . It also process
the radar raw data and
provides meteorological
data products.

LOW NOISE FRONT END
 1.SIGNAL
DETECTION IS
DONE.
 2. AMPLIFICATION
OF BACK
SCATTERED
SIGNALS
 3. CONVERT RF
SIGNALS TO FIRST
IF OF 460 MHZ

CIRCULATOR
 TRANSMISSION
PHASE:THE RECEIVER IS
BLOCKED BY T/R LIMITER WHICH
PREVENTS LEAKAGE FROM
CIRCULATOR.
 RECEIVING
PHASE:TRANSMIT PULSE IS
TERMINATED, T/R LIMITER OPEN
AND THUS CONNECTS THE
RECEIVED VIA THE CIRCULATOR
TO THE ANTENA

ANTENNA
UNIT
 IT CONSISTS
OF THE
PEDESTAL
AND THE S-
BAND
ANTENNA.
 Wg.7500Kgs

RADAR ANTENNA – PARABOLIC REFLECTOR

ANTENNA
 ANTENNA IS A
PRIME FOCUS
FEED
REFLECTOR
SYSTEM.
 PARABOLIC
REFLECTOR
DISH
CONTAINING 18
IDENTICAL PIE-
SHAPED PANELS.

PEDESTAL UNIT
 PEDESTAL IS A TWO AXIS ELEVATION-
 OVER-AZIMUTH DESIGN. IT IS CAPABLE
 OF CONTINUOUS ROTATION IN AZIMUTH
 AND ELEVATION SCANNING FOR 24 HRS.

APPLICATIONS OF RADAR
• MILITARY
 Major use of radar
 Air and sea surveillance; aircraft
control; weapons guidance and
control; navigation; Electronic
counter measures; Target
classification and identification

APPLICATIONS OF RADAR (Cont’d)
•SPACE
•Detection and tracking of satellites; Docking and Landing of space
crafts etc.
•SHIP AND AIRCRAFT NAVIGATION
•Weather avoidance; Collision warning; terrain avoidance; terrain
following; altimeter; ground mapping

APPLICATIONS OF RADAR (Cont’d)
•GROUND TRAFFIC
•Automotive radar; cruise control; collision warning; obstacle
detection; telemetry
METEOROLOGY
Storm warning;
precipitation measurement;
wind profiling;

TROPICAL CYCLONES
TROPICAL CYCLONES

STAGES OF DEVELOPMENT OF A CYCLONIC STORM
STAGES OF DEVELOPMENT OF A CYCLONIC STORM
SYSTEM Pressure
deficit in
hpa
Associated Wind
Speed in knots
(kmph)
Low pressure area 1.0 < 17 (<32)
Depression 1.0 – 3.0 17-27 (32–50)
Deep Depression 3.0 – 4.5 28-33 (51–59)
CyclonicStorm
T2.0/T2.5
4.5-8.5 34-47 (60-90)
Severe Cyclonic
Storm (SCS)
T3.0/T3.5
8.5-15.5 48-63 (90-119)
Very Severe Cyclonic
Storm (VSCS)
T4.0/T6.0
15.5-65.6 64-119 (119-220)
Super Cyclonic
Storm
>T6.0
>65.6 >119 (>220)

A CYCLONIC STORM AS SEEN FROM A HIGH
LEVEL (GEO STATIONERY) SATELLITE

1990 MAY CYCLONIC STORM AS SEEN ON
MACHILIPATNAM RADAR SCREEN

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