ROHINI RADAR

1. INDUSTRIAL TRAINING REPORT
(Submitted in partial fulfillment of the award of Degree of Bachelor of
Technology)
Done by
SHIV KUMAR KAPIL (1473720036)
At
ROHINI RADAR
GHAZIABAD UP
Submitted to
DEPARTMENT OF ELECTRICAL ENGINEERING
RAJKIYA ENGINEERING COLLEGE
AMBEDKAR NAGAR (U.P)-224122
(i)

2. CERTIFICATE
This is to certify that this Industrial Training Report is a work of SHIV KUMAR KAPIL
(1473720036) who carried out the work at BHARAT ELECTRONICS LIMITED
,GHAZIABAD U.P.
Date:
ProjectIn-charge;
MR. NITISH KUMAR YADAV
Assistant
Professor
REC, Ambedkar
Nagar
Approved by:
MR. MAYANK KUMAR GAUTAM
HOD, EE Department
REC, Ambedkar Nagar
(ii)

3. ACKNOWLEDGEMENT
It is always a pleasure to remind the fine people in the engineering program for their sincere
guidance. I received to uphold my practical as well as theoretical skills in engineering.
Firstly I would like to thank Dr. K.S. Verma (Director, Rajkiya Engineering
College) for meticulously planning academic curriculum in such a way that students are not
only academically sound but also industry ready by including such industrial training
patterns.
I would like to thanks Mr. Nitesh Kumar Yadav (Project in-charge) for the positive
attitude she showed for my work, always allowing me to question him and giving prompt
replies for my uncertainties in all the fields including educational social and managerial work.
I would like to acknowledge and my heartfelt gratitude to Mr. Mayank kumar
Gautam (HOD, ELECTRICAL ENGINEERING) and all faculty members who continuously
encouragement till this date.
Finally I would like to thanks staff members of bharat electronics limited ,ghaziabad u.p.
for the valuable information provided by them in their respective fields, and spending his
valuable time with me and guiding during the course of the training.
(iii)

4. CONTENTS
S.NO. NAME OF THE TOPIC PAGE NO.
CERTIFICATE………………………………... (ii)
ACKNOWLEDGEMENT……………………. (iii)
01 INTRODUCTION……………………………… 5
02 LITERATURE SURVEY ……………………….6
03 PRINCIPLE OF WORKING…………………….7
04 RADAR TRANSMITTER……………………….9
05 RADAR EQUATIONS………………………….10
06 TYPES OF RADAR……………………………..12
07 CONTINUOUS WAVE ………………………..13
08 PULSE RADAR………………………………...14
09 CLASSIFICATION ON THE BASIS…………..15
10 A-SCOPE……………………………………… 17
11 B-SCOPE……………………………………….17
12 PPI……………………………………………...18
14 PULSE DOPPLER RADAR…………………..19
15 NEW GATED CW RADAR…………………...20
16 FUTURE SCOPE………………………………22
17 ADVANTADGES & DISADVANTADGES….22
18 CONCLUSION………………………………..23
19 REFERENCES………………………………...24
(iv)

5. INTRODUCTION
RADAR is acronym for Radio Detection and Ranging. Today, the technology is so common
that the word has become standard English noun. The development of RADAR accelerated
and spread in middle and late 1930s with first successful demonstration in 1936. It uses
electromagnetic waves in microwave region to detect location, height, intensity and
movements of targets. It operates by radiating energy into space and detecting the echo
signals reflected from an object, or target. The reflected energy that is reflected to radar not
only indicates the presence of target, but by comparing the received echo signals with the
signals that were transmitted its location can be determined along with the other target related
information.
Radar is an active device. It utilizes its own radio energy to detect and track the target. It does
not depend on energy radiated by the target itself. The ability to detect a target at great
distances and to locate its position with high accuracy are two of the chief attributes of radar.
Earlier radar development was driven by military necessities. But, radar now it enjoys wide
range of application. One of the most common is the police traffic radar used for enforcing
speed limits. Another is color weather radar, other most famous application is air traffic
control system.
The Doppler Shift: This being the second principle of the radar. This property on applied to
radar used to determine the speed of the object. The frequency of the reflected wave can be
the same, greater or lower than the transmitted radio wave, if the reflected wave frequency is
less then this means that the target is moving away from the transmitter and if higher then
moving close to the transmitter and if constant then the target is not moving like a helicopter
hovering at a point. This can be used to predict the speeds of the target too.
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6. LITERATURE SURVEY
The history of radar starts with experiments by Heinrich Hertz in the late 19th century that
showed that radio waves were reflected by metallic objects. This possibility was suggested in
James Clerk Maxwell's seminal work on electromagnetism. However, it was not until the
early 20th century that systems able to use these principles were becoming widely available,
and it was German inventor Christian Hulsmeyer who first used them to build a simple ship
detection device intended to help avoid collisions in fog. Numerous similar systems were
developed over the next two decades.
The term RADAR was coined in 1940 by the United States Navy as an acronym for radio
detection and ranging, this was a cover for the highly secret technology. Thus, a true radar
system must both detect and provide range (distance) information for a target. Before 1934,
no single system gave this performance; some systems were omnidirectional and provided
ranging information, while others provided rough directional information but not range. A
key development was the use of pulses that were timed to provide ranging, which were sent
from large antennas that provided accurate directional information. Combining the two
allowed for accurate plotting of targets.
Applications of radar are very vast. Today, through its many and diverse applications, radar is
a key tool for remotely sensing and monitoring the environment and for the tracking and
surveillance of both civil and military objects.
1.1 FUTURE RESEARCH:
The focus is in the use of radar for surveillance and environmental monitoring. It brings
together research groups from the School of Electrical and Electronic Engineering and the
Discipline of Physics in the School of Science together with various external organizations
such as the Australian Defense Science and Technology Organisation, the Bureau of
Meteorology, the Australian Antarctic Division and commercial companies such as Raytheon
Australia.
Key research themes in the Centre are in the area of radar systems and technology, RF
propagation and radar signal processing.
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7. PRINCIPLE OF WORKING OF BASIC RADAR
Radar involves the transmission of pulses of electromagnetic waves by means of a directional
antenna. A radar system has a transmitter that emits radio waves called radar signals in
predetermined directions. Some of the pulses are reflected by objects that intercept them.
When these come into contact with an object they are usually reflected or scattered in many
directions.
Fig 1.1 Basic radar working
The working of basic radar is shown in fig 3.1. Radar signals are reflected especially well by
materials of considerable electrical conductivity. The reflections are picked up by a receiver,
processed electronically, and converted into visible form by means of a cathode-ray tube. The
range of the object is determined by measuring the time it takes for the radar signal to reach
the object and return. The object's location with respect to the radar unit is determined from
the direction in which the pulse was received. If the object is moving either toward or away
from the transmitter, there is a slight equivalent change in the frequency of the radio waves,
caused by the Doppler effect. The velocity of the object is measured by applying the Doppler
principle, if the object is approaching the radar unit, the frequency of the returned signal is
greater than the frequency of the transmitted signal,
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8. if the object is receding from the radar unit, the returned frequency is less and if the object
is not moving relative to the radar unit, the return signal will have the same frequency as the
transmitted signal. Radar receivers are usually, but not always, in the same location as the
transmitter. Although the reflected radar signals captured by the receiving antenna are usually
very weak, they can be strengthened by electronic amplifiers. More sophisticated methods of
signal processing are also used in order to recover useful radar signals.
The general requirement for any radar system is summarized as below:
1. The radar transmitter should remain silent during the echo period.
2. The transmitted pulse should be quite powerful to counter the attenuation during forward
and return journeys.
3. The received echo pulse being weak, the receiver should be extremely sensitive and at the
same time immune to noise signals. It should have necessary amplification, signal processing
circuitry.
4. The radar antenna should be highly directive and have a large gain so it can radiate a
strong signal and receive a weak pulse.
5. Pulse repetition frequency (prf) of radar should be high.
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9. RADAR TRANSMITTER:
The radar transmitter produces the short duration high-power RF pulses of energy that are
radiated into space by the antenna. The radar transmitter is required to have the following
technical and operating characteristics:
Fig 1.2 Transmitter signal
1) The transmitter must have the ability to generate the required mean RF power and the
required peak power.
2) The transmitter must have a suitable RF bandwidth.
3) The transmitter must have a high RF stability to meet signal processing requirements.
4) The transmitter must be easily modulated to meet waveform design requirements.
5) The transmitter must be efficient, reliable and easy to maintain and the life expectance.
RADAR RECEIVER:
The function of radar receiver is to detect the desired echo signals in the presence of noise,
interference and clutter, clutter is defined as any unwanted radar echo. These clutter make
difficult the detection of wanted signals. The design of radar receiver will depend not only on
the type of waveform to be detected but also on the nature of noise interference and clutter
echoes.
The radar receiver is required to:
1) Amplify the received signals without adding noise or introducing any form of distortions.
2) Reject interfering signals so that the required can be optimally detected.
3) Receiver should be designed to have sufficient gain, amplification, stability.
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10. FREE SPACE RADAR EQUATIONS:
The radar range equation relates the range of a radar to the characteristics of the transmitter,
receiver, antenna, target and the medium. Free space actually means that there are no
obstacles between radar antenna and the target. Also the free space medium is transparent and
homogenous with respect to the refractive index at radar frequency.
If the power of a radar transmitter is denoted by Pt and if an isotropic antenna (one which
radiates uniformly in all the directions) then the power density at a distance R from the radar
is equal to the transmitted power divided by the surface area of sphere of radius R i.e. power
density at a distance R from the isotropic source,
= Pt / 4ПR2 watts/m2 …(4.1)
Radar usually employ directive antennas to direct the transmitted power Pt into one
particular direction. The gain G of an antenna is a measure of the increased power radiated in
the direction of the target as compared with the power that would have been radiated from an
isotropic antenna.
Power density at a distance R from directive antenna of power gain
= Pt G / 4ПR2 watts/m2 …(4.2)
The target intercepts the portion of transmitted power and radiates it in various directions. A
measure of the incident power intercepted by the target and reradiated back in the direction of
radar is denoted as the radar cross-section of the target (б).
The total power intercepted by a target having an area ‘б’ is,
= (Pt G / 4П R2).б watts …(4.3)
Where б is also defined as the area of the target as seen by the radar. It has units of area in
m2.
б is a characteristic of a particular target and is a measure of its size and shape. The power
density of echo signal at the radar station is
= (PtGб / 4ПR2) . (1/4ПR2) = PtGб/ (4ПR2)2 watts …(4.4)
The radar antenna captures the portion of the echo power.
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11. Pr = PtGбAe / (4ПR2)2 watts …(4.5)
Maximum radar range is the distance beyond which the target cannot be detected. It occurs
when the received echo signal power Pr, just equals the minimum detectable signal (Smin).
i.e. when Pr = Smin, R = Rmax and when substituted in Eq. 11.5 we get,
Smin = PtGбAe / (4П)2 R4max
Rmax = [PtGбAe /(4П)2Smin]1/4 …(4.6)
From the antenna theory, we know that
G = 4ПAe / λ2
Where, λ= wavelength of the radiated energy,
Ae = effective area of receiving antenna,
G = transmitter gain
Since radar generally use the same antenna for both transmitter and receiver, the above
expression for G can be substituted in Rmax relation. Then,
Rmax = [Pt б Ae / (4П)2Smin]1/4
Rmax = [PtAe2б / 4Пλ2Smin]1/4 …(4.7)
Also, Ae = Gλ2 / 4П,
Rmax = [Pt(Gλ2/4П)2б / 4Пλ2Smin]1/4
Rmax = [Pt Gλ2б / (4П)2 Smin]1/4 …(4.8)
Equations (4.7) and (4.8) is the two alternate form of maximum radar range equation.
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12. TYPES OF RADAR
Depending on the desired information, radar sets must have different qualities and
technologies. One such different qualities and techniques radar sets are classified in fig. 5.1.
Fig. 1.3 types of radar
PRIMARY RADAR:
A Primary Radar transmits high-frequency signals toward the targets. The transmitted pulses
are reflected by the target and then received by the same radar. The reflected energy or the
echoes are further processed to extract target information. This means, unlike secondary radar
a primary radar unit receive its own emitted signals as an echo again.
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13. CONTINUOUS WAVE RADAR:
Continuous wave radars continuously transmit a high-frequency signal and the reflected
energy is also received and processed continuously. These radars have to ensure that the
transmitted energy doesn’t leak into the receiver (feedback connection). CW radars measures
radial velocity of the target using Doppler Effect. If there is relative motion between the radar
and the target, the shift in carrier frequency of the reflected wave becomes a measure of
targets relative velocity. The block diagram of continuous wave radar is shown in fig
Fig. 1.4 block diagram of continuous wave radar
The transmitter generates a continuous oscillations of frequency fo which is radiated by radar
antenna. A portion of this radiated energy is intercepted by target and reradiated energy is
collected by the receiver antenna. If the target is moving with the velocity vr relative to the
radar, the received signal will be shifted in frequency from the transmitted frequency fo by
the amount fd. The plus sign for an approaching target and minus sign for a receding target.
The received echo signal (fo±fd) enters the radar via the antenna and is mixed in a detector
mixer with a portion of a transmitter signal fo to produce the Doppler frequency fd. The
purpose of using a beat frequency amplifier is to eliminate echo from stationary targets and to
amplify the Doppler echo signal to a level where it can operate an indicating device such as
frequency meter.
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14. CW RADARS TYPES
Unmodulated:
An example of unmodulated CW radar is speed gauges used by the police. The transmitted
signal of these equipments is constant in amplitude and frequency. CW radar transmitting
unmodulated power can measure the speed only by using the Doppler-effect. It cannot
measure a range and it cannot differ between two reflecting objects.
Modulated:
Unmodulated CW radars have the disadvantage that they cannot measure range, because run
time measurements is not possible (and necessary) in unmodulated CW-radars. This is
achieved in modulated CW radars using the frequency shifting method. In this method, a
signal that constantly changes in frequency around a fixed reference is used to detect
stationary objects. Frequency is swept repeatedly between f1 and f2. On examining the
received reflected frequencies (and with the knowledge of the transmitted frequency), range
calculation can be done.
SECONDARY RADAR:
Secondary radar units work with active answer signals. In addition to primary radar, this type
of radar uses a transponder on the airborne target The ground unit, called interrogator,
transmits coded pulses (after modulation) towards the target. The transponder on the airborne
object receives the pulse, decodes it, induces the coder to prepare the suitable answer, and
then transmits the interrogated information back to the ground unit. The interrogator/ground
unit demodulates the answer. The information is displayed on the display of the primary
radar. The secondary radar unit transmits and also receives high-frequency impulses.
PULSE RADAR:
A pulse radar is a radar device that emits short and powerful pulses and in the silent period
receives the echo signals. In contrast to the continuous wave radar the transmitter is turned
off before the measurement is finished.
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15. CLASSIFICATION ON THE BASIS OF USE
Fig 1.5 Classification on the basis of use
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16. RADAR ANTENNA
An antenna either receives energy from an electromagnetic field or radiates electromagnetic
waves produced by a high frequency generator.
Fig 1.6 Parabolic antenna Fig 1.7Cassegrain antenna
Fig 1.8 Slot antenna
RADAR DISPLAY:
 A-SCOPE
 B-SCOPE
 PLAN-POSITION INDICATOR(PPI)
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17. A-SCOPE:
Presents only the range to the target and the relative strength of the echo.
Fig 1.9 A-Scope
B-SCOPE:
It provides a 2-D representation in which horizontal axis represents measurement of azimuth
(bearing) and vertical axis represents the measurement of the range.
Fig 1.10 B-Scope
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18. PLAN-POSITION INDICATOR (PPI):
It is an intensity-modulation type display system which indicates both range and bearing
angle of the target simultaneously in polar co-ordinate.The distance of the bright spot
radiating outward from the centre gives the range or the distance of the target from the radar
transmitter while the direction in which the spot deflects at certain instant corresponds to the
direction of radar antenna (i.e. target direction) at that instant.
Fig 2.1 plan-position indicator
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19. MOVING TARGET INDICATOR RADAR
This radar uses Doppler effect .
• MTI radar distinguishes between moving targets and stationary targets.
• The MTI Radar uses low pulse repetition frequency (PRF) to avoid range ambiguities.
• MTI Radars can have Doppler ambiguities.
MTI APPLICATION IN UAVS
area of cross-cueing applications Moving Target Indicator (MTI).
f UAVS used by US Air force.
PULSE DOPPLER RADAR
• Pulse Doppler Radar uses high PRF to avoid Doppler ambiguities, but it can have numerous
range ambiguities.
• In MTI radar the prf is chosen so that there are no range ambiguities, but there are usually
many Doppler ambiguities, or blind speeds.
• A radar that increases its prf high enough to avoid the problem of blind speeds is called a
pulse Doppler radar.
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20. A NEW GATED CW RADAR
Gated-CW radars have offered a high level of performance versus cost value trade-off to the
RCS measurement community for a number of years. These radars operate on the principle of
using a pulsed transmit signal and gated receive path, in conjunction with an IF section of the
receiver that is restricted in bandwidth such that it does not pass the entire received pulse
spectrum of frequency components, but rather only the central component. The gated-CW
radar experiences additional losses termed duty cycle losses, as these losses are proportional
to the duty cycle of the transmitted waveform. The gated-CW radars are very efficient for
indoor use as the duty cycle losses may be easily compensated. Moreover, the gated-CW
radar generally provides better accuracy and effective I/Q circularity, and is lower cost than
an equivalent pulsed-IF radar. Gated-CW radars have generally been implemented using
vector network analyzers (VNAs) as the IF receivers. This unit has been a reliable, high
performance unit for a number of years. However, Agilent Technologies has recently
introduced a new series of instruments, the Performance Network Analyzer (PNA) series,
which are ideal for use in gated-CW radars. These units are Windows based instruments
whose features provide several key enhancements to the implementation of gated CW radars:
1)An order of magnitude or better increase in data acquisition speed for multi-frequency
measurements 2) Improved sensitivity as well as flexibility in the selection of appropriate IF
bandwidth 3) The ability to easily remote the control of the instrument from the unit front
panel, thus allowing the instrument to be located near the front end RF instrumentation,
resulting in additional performance improvements.
GATED-CW RADAR CONFIGURATION:
The gated-CW radar typically comprises the following key elements:
1) Pulse Modulator Assembly
2) Pulse Modulator Timing Unit
3) RF Synthesizer
4) Remote Mixer System (if required)
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21. 5) Data Acquisition System
6) Positioning System
7) Antenna System
In the case of a microwave band (e.g., 2-18 GHz) radar, a remote mixer system was often
utilized to allow the point of RF to IF conversion to be placed in the anechoic chamber near
the antennas, along with the pulse modulation functional hardware. In this manner, the VNA
front panel could be located in the control room to allow for manual operation of the radar.
The new gated-CW radar system utilizing the PNA now retains the full functionality of
manual operation of the radar while allowing the unit to be located in the anechoic chamber
next to the pulse modulator and antennas. Manual operation is achieved by locating a remote
keyboard, mouse, and monitor in the control room. Thus, the remote mixers for the primary
microwave band can be eliminated as RF cable lengths can be kept short. The resulting radar
configuration is a simpler, higher performance, yet less costly alternative to gated-CW radar
implementation.
SYSTEM PERFORMANCE:
The system performance is characterized by high sensitivity, high speed acquisition, and
flexibility in setting up various measurement scenarios. The sensitivity is derived from the
use of a power amplifier inside the pulse modulator module, in conjunction with the excellent
sensitivity of the PNA preceded by a low noise amplifier on the receive side. Limiting in the
receive side chain as well as high isolation antennas such as the FR 6400 series of diagonal
horns, used in conjunction with the pulse modulation capability of the radar, provides a
highly clutter-free environment that effectively takes advantage of the available system
sensitivity. Data acquisition speed is greatly increased in the radar over that previously
available by taking advantage of the order of magnitude improvement in frequency switching
speed offered by the PNA synthesizer over the previous generation 8360 series synthesizer,
as well as the improvement in sampling speed. With the wide range of IF bandwidth choices
available in the PNA, the speed/sensitivity trade off can easily be optimized as the
measurement scenario requires.
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22. ADVANTAGES:
1) It uses low transmitting power, low power consumption.
2) It has simple circuitry and it is small in size.
3) Unlike pulse radar CW radar is able to detect an aircraft inspite of fixed objects.
DISADVANTAGES:
1) Practical application of CW radar is limited by the fact that several targets at a given
bearing tend to cause confusion.
2) Range discrimination can be achieved only by introducing very costly complex circuitry.
3) It is not capable of indicating the range of target an can show only its velocity.
FUTURE SCOPE OF STEALTH TECHNOLOGY
Stealth technology is clearly the future of air combat. In the future, as air defence systems
grow more accurate and deadly, stealth technology can be a factor for a decisive by a country
over the other. In the future, stealth technology will not only be incorporated in fighters and
bombers but also in ships, helicopters, tanks and transport planes. These are evident from the
RAH66 "Comanche" and the Sea Shadow ship. Ever since the Wright brothers flew the first
powered flight, the advancements in this particular field of technology have seen staggering
heights. Stealth technology is just one of the advancements that we have seen. In due course
of time we can see many improvements in the field of military aviation which would one-day
even make stealth technology obsolete.
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23. CONCLUSION:
RADAR is used to find velocity, range and position of the object.
superior penetration capability through any type
of weather condition.
.
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24. REFERENCES
[1] M. Kulkarni, “Microwave and Radar Engineering”, 3rd edition, Umesh Publication, 2003,
pp. 493 –
[2] Merri.I.skolnik, “Intoduction to Radar System”, 3rd edition, Tata McGraw Hill,
[3]“Types of Radar”, Engineers Garage,2012[online]. Available:
http://www.engineersgarage. com/articles/type-of-
[4] “Types of Radar”, Cristian Wolff, June 10, 2012[online].
Available:http://www.radartutorial. eu/02.basics/rp05.en.html [accessed: September
[5] “Radar Basics”, Infoplease, September 22, 2012 [online]. Available:
[6] John F.Autin, John Caserta, Mark A.Bates, “A New Gated CW Radar Implementation”
Horsham, 2010.
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