OPERATION OF RADAR“RADIO DETECTION AND

RANGING”

BASIC DESIGN OF A RADAR SYSTEM

PULSE DOPPLER RADAR

DOPPLER EFFECT

BASIC DESIGN OF A RADAR SYSTEM

FIGURES TRANSMITTER

DUPLEXER

RECEIVER RADAR ANTENNA

INDICATOR

TRANSMITTER PRODUCES THE SHORT DURATION HIGH POWER RF PULSES OF ENERGY THAT ARE INTO SPACE BY THE ANTENNA.

DUPLEXER ALTERNATELY SWITCHES THE ANTENNA BET. THE TRANSMITTER AND RECEIVER SO THAT ONLY ONE ANTENNA IS TO BE USED.

IT PRESENT TO THE OBSERVER A CONTINUOUS , EASILY UNDERSTAND, GRAPHIC PICTURE OF THE RELATIVE POSITION OF RADAR TARGETS.

IT AMPLIFY AND DEMODULATE THE RECEIVED RF-SIGNALS.

IT TRANSFERS THE ENERGY TO SIGNALS IN SPACE WITH THE REQUIRED DISTRIBUTION AND EFFICIENCY.

PULSE DOPPLER RADAR

-PULSE DOPPLER IS BASED ON DOPPLER PHENOMENON.

WHAT IS A PULSE DOPPLER?

“DOPPLER EFFECT”-DOPPLER EFFECT IS THE CHANGE IN

FREQUENCY OF A WAVE CAUSED BY RELATIVE MOTION BETWEEN THE SOURCE OF THE WAVE AND THE OBSERVER.

DOPPLER RADAR MAKES USE OF DOPPLER EFFECT TO PRODUCE VELOCITY DATA ABOUT THE OBJECT AT A DISTANT.

IT DOES THIS BY BEAMING A MICROWAVE SYSTEM SIGNAL TOWARDS A DESIRED TARGET AND LISTENING ITS REFLECTION AND THEN ANALYZING HOW THE FREQUENCY OF THE RETURNED SIGNAL HAS BEEN ALTERED BY THE OBJECTS MOTION.

“OPERATION OF A DOPPLER RADAR”PULSE DOPPLER SIGNAL PROCESSINGFIRST. ENVIRONMENTFirstly the antenna transmit the dozens of pulses. Energy from each transmit pulse propagates in space until some of them bounce back by the reflector.

THREE TYPES OF TRANSMITTERS USED COMMONLY IN WEATHER RADARS:

APPLICATIONS OF A DOPPLER EFFECT

CONTINUOUS WAVE RADAR

• A T Y P E O F   R A D A R S Y S T E M W H E R E A K N O W N S TA B L E F R E Q U E N C Y   C O N T I N O U S W AV E R A D I O E N E R G Y I S T R A N S M I T T E D A N D T H E N R E C E I V E D F R O M A N Y R E F L E C T I N G O B J E C T S .

•   C O N T I N U O U S - W A V E ( C W ) R A D A R U S E S D O P P L E R , W H I C H R E N D E R S T H E R A D A R I M M U N E T O I N T E R F E R E N C E F R O M L A R G E S TAT I O N A R Y O B J E C T S A N D S L O W M O V I N G   C L U T T E R .

DOPPLER FREQUENCY SHIFTS

CONTINUOUS WAVE RADAR COMPONENTS

Discriminator AMP Mixer

CW RFOscillator

Indicator

OUT

IN

Transmitter Antenna

Antenna

BLOCK

DIAGRAM

RADAR WAVE MODULATIONAM P L I T UDE M O DUL AT I O N

–Vary the amplitude of the carrier sine waveF RE Q UE NCY M O DU L AT IO N

–Vary the frequency of the carrier sine waveP UL SE - AM P L I T UD E M O DUL AT I O N

–Vary the amplitude of the pulsesP UL SE - F RE Q UE NCY M O DU L AT I O N

–Vary the Frequency at which the pulses occur