HOW RADAR WORKS

2. RADAR
AN APPLICATION OF
ELECTOMAGNETIC WAVES

3. GROUP MEMBERS
TASHFEEN SHARF SHABBIR BEE-F16-001
SHERYAR BASHIR BEE-F16-065
TOUQIR KHAN BEE-F16-059
29/12/2018 3UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

4. OUTLINE
29/12/2018 4
1. Introduction To Radar
2. History
3. Basic Radar Principles
4. Components Of Radar System
5. Factors Effects On Radar
6. Stealth Technology
7. Advantages & Dis-Advantages
8. Application
9. Conclusion
UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

5. INTRODUCTIO
N
• RADIO
DETECTION
AND RANGING
“R A D A R”
29/12/2018 5
UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

6. WORKING PROCESS OF
RADAR
• BATS USE A BASIC FORM OF
RADAR.
• THEY SEND SOUND WAVES
THAT REFLECT OF AN OBJECT
JUST AS ELECTRIC RADAR
SYSTEMS DO. 29/12/2018 6UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

7. HISTOR
Y
• THE HISTORY OF RADAR STARTS WITH EXPERIMENTS
BY HEINRICH HERTZ IN THE LATE 19TH CENTURY.
• THE FIRST FORM OF RADAR CREATED BY HUMANS
WAS THE TELEMOBILESCOPE.
TELEMOBILESCOPE ( THE FIRST FORM OF RADAR )
• IT WAS MAINLY USED TO DETECT SHIPS TO AVOID
COLLISIONS
29/12/2018 7UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

8. RADAR FREQUENCY BANDS
29/12/2018 8UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

9. PRINCIPLE OF
OPERATION
• REFLECTION OF
ELECTROMAGNETIC
WAVES
• MEASUREMENT OF
RUNNING TIME OF
TRANSMITTED
PULSES 29/12/2018 9UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

10. DETERMINING RANGE WITH PULSE
RADAR
• DETERMINING RANGE WITH PULSE RADAR
• RANGE = C*T/2
• C = 3 X 108 M/SEC
• T IS TIME TO RECEIVE RETURN
• DIVIDE BY 2 BECAUSE PULSE TRAVELED TO OBJECT AND
BACK
29/12/2018 10UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

11. DOPPLER EFFECT
• THE DOPPLER EFFECT IS THE CHANGE IN FREQUENCY.
• OCCURS WHEN A SOURCE AND A TARGET ARE IN
RELATIVE MOTION.
• THE DOPPLER AFFECT CAN BE USED IN A CW RADAR IN
ORDER TO DETERMINE VELOCITY.
29/12/2018 11UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

12. DOPPLER EFFECT THEORY
• FD = 2 𝑉𝑟 /Λ
• FD = DOPPLER SHIFT
• 𝑉𝑟 = RELATIVE VELOCITY OF TARGET WITH RESPECT TO
RADAR
29/12/2018 12UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

13. A BASIC RADAR SYSTEM
29/12/2018 13
UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

14. Radars create an
electromagnetic (EM) pulse
that is focused by an
antenna, and then
transmitted through the
atmosphere
(Figure A).
Objects in the path of the
transmitted EM pulse, called
"targets" or "echoes," scatter
most of the energy, but some
will be reflected back toward
the radar (Figure B).The receiving antenna
(normally also the
transmitting antenna)
gathers back-scattered
radiation and feeds it to a
"receiver."
29/12/2018 14UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

15. target is scattered in
all
directions. The larger
the
target, the stronger
the
scattered signal
(Figure C).
Also, the more targets, the
stronger the return signal,
that is, the targets combine
to produce a stronger
signal
(Figure D).
Reflectivity magnitude
is
related to the number
and
size of the targets
encountered.
The radar measures
the
returned signal,
generally
called the
"reflectivity."
29/12/2018 15UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

16. DUPLEXER
• THE DUPLEXER IS A
WAVEGUIDE SWITCH
• IT PASSES THE TRANSMITTED
HIGH-POWER PULSES TO THE
ANTENNA AND THE RECEIVED
ECHOES FROM THE ANTENNA
TO THE RECEIVER
• DUPLEXER SWITCHES
AUTOMATICALLY BASED ON
THE TIMING ,CONTROL
SIGNAL
29/12/2018 16UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

17. ANTENNA SYSTEM
• RADIATION FROM A
DIRECTIONAL SOURCE
• THE ENERGY IS FOCUSED IN A
GIVEN DIRECTIONS
• THIS ALLOWS THE ENERGY TO
TRAVEL
• FURTHER, HENCE A GAIN, G,
COMPARED TO THE ISOTROPIC
SOURCE
29/12/2018 17UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

18. ANTENNA SYSTEM
• COASTAL SURVEILLANCE AND VESSEL TRAFFIC SYSTEM RADARS ARE
• USUALLY FAN OR INVERSE-COSECANT-SQUARED BEAMS
29/12/2018 18UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

19. 29/12/2018 19
RADAR
PULSE
CONTINOUS WAVE
UNMODULAT
E
DOPPLER
MTI
MODULATE
SECONDARY
PRIMARY
TYPES
OF
RADAR
UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

20. FACTORS THAT AFFECT RADAR
PERFORMANCE
• SIGNAL RECEPTION
• RECEIVER BANDWIDTH
• PULSE SHAPE
• POWER RELATION
• BEAM WIDTH
• PULSE REPETITION FREQUENCY
• ANTENNA GAIN
• RADAR CROSS SECTION OF TARGET
• SIGNAL-TO-NOISE RATIO
• RECEIVER SENSITIVITY
• PULSE COMPRESSION
• SCAN RATE
• MECHANICAL
• ELECTRONIC
• CARRIER FREQUENCY
• ANTENNA APERTURE
29/12/2018 20UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

21. STEALTH TECHNOLOGY
• MATERIAL.
• SHAPE, DIRECTIVITY AND ORIENTATION.
• ACTIVE CANCELLATION.
• RADAR ABSORBENT PAINT.
29/12/2018 21UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

22. MATERIAL
• MATERIALS SUCH AS METAL ARE STRONGLY RADAR REFLECTIVE AND
TEND TO PRODUCE STRONG SIGNALS. WOOD AND CLOTH (SUCH AS
PORTIONS OF PLANES AND BALLOONS USED TO BE COMMONLY MADE)
OR PLASTIC AND FIBREGLASS ARE LESS REFLECTIVE OR INDEED
TRANSPARENT TO RADAR MAKING THEM SUITABLE . EVEN A VERY THIN
LAYER OF METAL CAN MAKE AN OBJECT STRONGLY RADAR REFLECTIVE.
• SUBMARINES HAVE EXTENSIVE USAGE OF RUBBER MOUNTINGS TO
ISOLATE AND AVOID MECHANICAL NOISES THAT COULD REVEAL
LOCATIONS TO UNDERWATER PASSIVE SONAR ARRAYS. 29/12/2018 22UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

23. SHAPE, DIRECTIVITY AND ORIENTATION
• THE SURFACES OF THE F-117A ARE DESIGNED TO BE FLAT AND VERY ANGLED. THIS
HAS THE EFFECT THAT RADAR WILL BE INCIDENT AT A LARGE ANGLE (TO THE
NORMAL RAY) THATWILL THEN BOUNCE OFF AT A SIMILARLY HIGH REFLECTED
ANGLE; IT IS FORWARD-SCATTERED.
• THE EDGES ARE SHARP TO PREVENT THERE BEING ROUNDED SURFACES.
ROUNDEDSURFACES WILL OFTEN HAVE SOME PORTION OF THE SURFACE NORMAL TO
THE RADARSOURCE. AS ANY RAY INCIDENT ALONG THE NORMAL WILL REFLECT
BACK ALONG THE
• NORMAL THIS WILL MAKE FOR A STRONG REFLECTED SIGNAL.WITH PURPOSE
SHAPING, THE SHAPE OF THE TARGET’S REFLECTING SURFACES IS DESIGNEDSUCH
THAT THEY REFLECT ENERGY AWAY FROM THE SOURCE. 29/12/2018 23UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

24. ACTIVE CANCELLATION
• WITH ACTIVE CANCELLATION, THE TARGET GENERATES A
RADAR SIGNAL EQUAL IN INTENSITY BUT OPPOSITE IN
PHASE TO THE PREDICTED REFLECTION OF AN INCIDENT
RADAR SIGNAL .
• THIS CREATES DESTRUCTIVE INTERFERENCE BETWEEN
THE REFLECTED AND GENERATED SIGNALS ,RESULTING IN
REDUCED RCS. 29/12/2018 24UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

25. RADAR ABSORBENT PAINT
• THE SR-71 BLACKBIRD AND OTHER PLANES WERE PAINTED WITH A SPECIAL
"IRON BALL PAINT“. THIS CONSISTED OF SMALL METALLIC-COATED BALLS.
RADAR ENERGY IS CONVERTED TO HEAT RATHER THAN BEING REFLECTED.
• ONE OF THE MOST COMMONLY KNOWN TYPES OF RAM IS IRON BALL PAINT. IT
CONTAINS TINY SPHERES COATED WITH CARBONYL IRON OR FERRITE. RADAR
WAVES INDUCE MOLECULAR OSCILLATIONS FROM THE ALTERNATING MAGNETIC
FIELD IN THIS PAINT, WHICH LEADS TO CONVERSION OF THE RADAR ENERGY
INTO HEAT. THE HEAT IS THEN TRANSFERRED TO THE AIRCRAFT AND
DISSIPATED.
29/12/2018 25UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

26. 29/12/2018 26UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

27. 29/12/2018 27UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

28. ADVANTAGES OF MILITARY RADARS
• ALL-WEATHER DAY AND NIGHT CAPABILITY.
• MULTIPLE TARGET HANDLING AND ENGAGEMENT CAPABILITY.
• SHORT AND FAST REACTION TIME BETWEEN TARGET DETECTION AND READY TO
FIRE MOMENT.
• EASY TO OPERATE AND HENCE LOW MANNING REQUIREMENTS AND STRESS
REDUCTION UNDER SEVERE
CONDITIONS
• HIGHLY MOBILE SYSTEM, TO BE USED IN ALL KIND OF TERRAIN
• FLEXIBLE WEAPON INTEGRATION, AND UNLIMITED NUMBER OF
• SINGLE AIR DEFENCE WEAPONS CAN BE PROVIDED WITH TARGET DATA.
29/12/2018 28UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

29. DISADVANTAGES
• TIME - RADAR CAN TAKE UP TO 2 SECONDS TO LOCK ON
• RADAR HAS WIDE BEAM SPREAD (50 FT DIAMETER OVER 200
FT RANGE).
• CANNOT TRACK IF DECELERATION IS GREATER THAN ONE
MPH/SECOND.
• LARGE TARGETS CLOSE TO RADAR CAN SATURATE RECEIVER.
• HAND-HELD MODULATION CAN FALSIFY READINGS.
29/12/2018 29UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

30. FIELDS OF APPLICATION
• MILITARY
• REMOTE SENSING
• AIR TRAFFIC CONTROL
• LAW ENFORCEMENT AND HIGHWAY
• SECURITY
• AIRCRAFT SAFETY AND NAVIGATION
• SHIP SAFETY
• SPACE
• MISCELLANEOUS APPLICATIONS
29/12/2018 30UNIVERSITY OF LAHORE ISLAMABAD CAMPUS

31. CONCLUSION
• RADAR IS USED TO FIND VELOCITY,
RANGE ANDPOSITION OF THE OBJECT.
• LIDER IS ADVANCED TYPE OF RADAR
WHICH USES VISIBLE LIGHT FROM
LASER
• TECHNOLOGY WILL CONTINUE TO
GROW, AND RADAR WILL ADVANCE
WITH IT.
• GROWTH OF RADAR TECHNOLOGIES
WILL BE ACCOMPANIED BY A WIDER
VARIETY OF APPLICATIONS.
• RADAR IN THE FUTURE WILL MOST
LIKELY BE AS COMMON AS CELL
29/12/2018 31UNIVERSITY OF LAHORE ISLAMABAD CAMPUS