Principle and basic design of radar system.

1. raghu engineering college
(AUTONOMOUS)
Department of Electronics and Communication Engineering
SIGNALS AND SYSTEM CASE
STUDY
TOPIC: RADAR SYSTEM
BY
P. SAI TEJA

2. Contents
► Introduction
► History
► Radar principle
► Basic design
► Radar range measurement
► Radar range equation
► Applications
► Advantages
► Disadvantages
► Conclusion

3. ABSTRACT
In this presentation we know about the introduction and
history about radars. We can know the principle and basic
design of radar system. We know about the applications,
advantages and disadvantages. It is used to detection and
ranging of objects.

4. INTRODUCTION
► Radar – radio detection and ranging.
► RADAR is a way to detect and study far off targets by
transmitting a radio pulse in the direction of the target
and observing the reflection of the wave.
► Radar is an object-detection system that uses radio
waves to determine the range, angle, or velocity of
objects.

5. History
► It was developed in the early 1900s.
► Robert Watson-Watt developed radar to detect
approaching storms with the help of radio waves.
► During world war Watson and his assistant Arnold
Wilkins realized they could use the technology they
were developing to detect approaching enemy
aircraft.

6. Radar principle
► The electronic principle on which radar operates is very
similar to the principle of sound-wave reflection.
► The radio-frequency (rf) energy is transmitted to and reflected
from the reflecting object.
► A small portion of the reflected energy returns to the radar set.
► This returned energy is called an ECHO, just as it is in sound
terminology.
► Radar sets use the echo to determine the direction
and distance of the reflecting object.

8. Basic design of a radar system
► The radar antenna illuminates the target with a
microwave signal, which is then reflected and picked
up by a receiving device.
► The electrical signal picked up by the receiving
antenna is called echo or return.
► The radar signal is generated by a powerful
transmitter and received by a highly sensitive
receiver.
► Radar signals can be displayed on the radar display
system.

10. ► Transmitter
The radar transmitter produces the short duration
high-power rf pulses of energy that are into space by
the antenna.
► Duplexer
The duplexer alternately switches the antenna
between the transmitter and receiver so that only one
antenna need be used. This switching is necessary
because the high-power pulses of the transmitter
would destroy the receiver if energy were allowed to
enter the receiver.
► Receiver
The receivers amplify and demodulate the received
RF-signals. The receiver provides video signals on
the output.

11. ► Radar Antenna
The Antenna transfers the transmitter energy to
signals in space with the required distribution and
efficiency.
► Indicator
The indicator should present to the observer a
continuous, easily understandable, graphic picture of
the relative position of radar targets.
The radar screen displays the produced from the echo
signals bright blibs.

12. Radar Range
Measurement
Target
c τ
• Target range =
2
where c = speed of light
τ = round trip ti me

13. Radar range equation
The equation is used to find out the Radar Signal range
Power density
G= Gain of
antenna
A= Area of
antenna
σ= Area of target
R= Range

14. Example fence radar: BMEWS
14
BMEWS: Ballistic Missile Early Warning System

15. Applications
► Military Applications:
► The RADAR has 3 major applications in Military:
1. In air defense it is used for target detection, target recognition and weapon
control (directing the weapon to the tracked targets).
2. In missile system to guide the weapon.
3. Identifying enemy locations in map.
► Air Traffic Control:
► Three RADAR has 3 major applications in Air Traffic control:
1. To control air traffic near airports. The Air Surveillance RADAR is used to
detect and display the aircraft’s position in the airport terminals.
2. To guide the aircraft to land in bad weather using Precision Approach
RADAR.
3. To scan the airport surface for aircraft and ground vehicle positions

16. ► Remote Sensing: RADAR can be used for observing weather or observing
planetary positions and monitoring sea ice to ensure smooth route for ships.
► Ground Traffic Control: RADAR can also be used by traffic police to determine
speed of the vehicle, controlling the movement of vehicles by giving warnings
about presence of other vehicles or any other obstacles behind them.
► Space:
► RADAR has 3 major applications:
1. To guide the space vehicle for safe landing on moon
2. To observe the planetary systems
3. To detect and track satellites
4. To monitor the meteors

17. Advantages
► The radar can see through the medium consisting of fog, snow,
rain, darkness, clouds etc.
➨Radar signal can penetrate and see through insulators.
➨It can help find out following parameters of object or target
• Range
• Angular Position
• Location of Target
• Velocity of Target
➨It can distinguish fixed as well as moving target types.

18. Disadvantages
► It can not distinguish and resolve multiple targets
which are very close like our eye.
► It can not recognize color of the targets.
► It can not see targets which are placed behind some
conducting sheets.

19. Conclusion
LIDAR is the advanced type of radar which uses visible
light from laser. The radar machine give the exact
location of the object. By the radar data meteorologist
forecast about the flood, cyclone. Heavy rainfall, and
hail they give warning to the people to be careful.