radar bullet

Radar bullet seminar 2011

RADAR BULLET

Dept of ECE VJEC,chemperi


ABSTRACT

Radar bullet is a special type of bullet the main use of radar bullet is to find

landmines without setting foot into the ground .This consists of firing a special

bullet into ground from a helicopter which could pinpoint buried landmines.

Anti -personal mines claims seventy new victims every day. This weapon is

particularly cruel on children whose bodies being smaller and closer to the blast

are more likely to sustain serious injury. The severe disabilities and

psychological trauma that follow the blast mean these children will have to be

looked after for many years.

Dept of ECE VJEC,chemperi1


CONTENTS

INTRODUCTION

ABOUT RADAR BULLET

PRINCIPLES

EXPERIMENTAL SET UP

MAGNETIC FLUX COMPRESSION

FIELD TEST

ADVANTAGE

DISADVANTAGE

APPLICATION

FUTURE PROSPECTS

CONCLUSION



INTRODUCTION

Radar bullet is a relatively new discovery that was invented in mid 99 in

the US. It is used for detecting land mines. And this discovery finds a very

important prospect as about 139 countries singed a treaty in favor of banning

anti-personal mines. This treaty was signed during the second week of March

1999 in Ottawa Canada.

Anti -personal mines claims seventy new victims every day. This weapon

is particularly cruel on children whose bodies being smaller and closer to the

blast. Are more likely to sustain serious injury. The severe disabilities and

psychological trauma that follow the blast mean these children will have to be

looked after for many year.

A child injured at the age of ten will need about 25 artificial limbs during

their life time. The cost is @3000, a huge sum to pay in countries where people

earn as little as $10 a month between 1979 and 19960, the red cross fitted over

70,000 amputees with artificial limbs. And the landmines problem is still

growing. Therefore considering these factors the discovery of radar bullet is

really a big boost to our world as we launches into the 21't century.



Technologies are used for landmine detection are:

Metal detectors--- capable of finding even low-metal content mines in

mineralized soils.

Nuclear magnetic resonance, fast neutron activation and thermal

neutron activation.

Thermal imaging and electro-optical sensors--- detect evidence of

buried objects.

Biological sensors such as dogs, pigs, bees and birds.

Chemical sensors such as thermal fluorescence--- detect airborne and

waterborne presence of explosive vapors.

In this discussion, we will concentrate on Radar This ultra wide band radar

provides centimeter resolution to locate even small targets. There are two

distinct types of Radar, time-domain and frequency domain. Time domain

or impulse Radar transmits discrete pulses of nanosecond duration and

digitizes the returns at GHz sample rates. Frequency domain radar systems

transmit single frequencies either uniquely, as a series of frequency steps, or

as a chirp. The amplitude and phase of the return signal is measured. The

resulting data is converted to the time domain. Radar operates by detecting

the dielectric contrasts in the soils, which allows it to locate even non

metallic mines.



ABOUT RADAR BULLET

Radar bullet is a special type of bullet the main use of radar bullet is to find

landmines without setting foot into the ground .This consists of firing a

special bullet into ground from a helicopter which could pinpoint buried

landmines

The bullet emits a radar pulse as it grinds to halt .This pulse strikes the mine

and its image gets available on the computer in the helicopter, offering a

safe and efficient way of finding land mines In this discussion we deal with

buried anti-tank (AT) and anti-personnel (AP) landmines which require

close approach or contact to activate. AT mines range from about 15 to 35

cm in size. They are typically buried up to 40cm deep, but they can also be

deployed on the surface of a road to block a column of machinery. AP

mines range from about 5 to 15cm in size. AT mines which are designed to

impede the progress of destroy vehicles and AP mines which are designed

to kill and maim people.

In this discussion, we will concentrate on Radar This ultra wide band radar

provides centimeter resolution to locate even small targets. There are two

distinct types of radar bullet time-domain and frequency domain. Time

domain or impulse radar bullet transmits discrete pulses of nanosecond

duration and digitizes the returns at GHz sample rates. Frequency domain



radar systems transmit single frequencies either uniquely, as a series of

frequency steps, or as a chirp. The amplitude and phase of the return signal

is measured. The resulting data is converted to the time domain. Radar

operates by detecting the dielectric contrasts in the soils, which allows it to

locate even non metallic mines.

In this discussion we deal with buried anti-tank (AT) and anti-

personnel (AP) landmines which require close approach or contact to

activate. AT mines range from about 15 to 35 cm in size. They are typically

buried up to 40cm deep, but they can also be deployed on the surface of a

road to block a column of machinery. AP mines range from about 5 to 15cm

in size. AT mines which are designed to impede the progress of destroy

vehicles and AP mines which are designed to kill and maim people.

In this discussion, we will concentrate on Radar bullet This ultra wide

band radar provides centimeter resolution to locate even small targets.

There are two distinct types of Radar bullet time-domain and frequency

domain. Time domain or impulse Radar bullet transmits discrete pulses of

nanosecond duration and digitizes the returns at GHz sample rates.

Frequency domain



Radar bullet systems transmit single frequencies either uniquely, as a series

of frequency steps, or as a chirp. The amplitude and phase of the return

signal is measured. The resulting data is converted to the time domain

In this discussion we deal with buried anti-tank (AT) and anti-personnel

(AP) landmines which require close approach or contact to activate. AT

mines range from about 15 to 35 cm in size. They are typically buried up to

40cm deep, but they can also be deployed on the surface of a road to block a

column of machinery. AP mines range from about 5 to 15cm in size. AT

mines which are designed to impede the progress of destroy vehicles and

AP mines which are designed to kill and maim people.



PRINCIPLES

Radar is radio detection and ranging. Radar makes use of radio waves to

detect and locate objects. Radar is a sensor, its purpose is to provide estimates

of certain characteristic if its surroundings, most commonly the presence and

motion of aircrafts, ships or vehicles.

Radar operates by transmitting electromagnetic energy into the

surroundings and detecting energy reflected by objects. If a narrow beam of

this energy is transmitted by the directive antenna, the direction from which

reflections come and hence the bearing of the object may be estimated. The

distance to the reflecting object is estimated by measuring the period between

the transmission of the radar pulse and reception of the echo. In radar bullet

principle, the change of medium by the waves must be taken into

consideration.

Radar is basically a means of gathering information about distant

objects, or targets, by sending electromagnetic waves at them and analyzing

the echoes. It was evolved during the years just before World War II,

independently and more or less simultaneously in Great Britain, the United



States, Germany and France. At first, it was used as an all-weather method of

detecting approaching aircraft, and later for many other purpose. The word

itself is an acronym, coined in 1942 by the U.S. Navy, from the words radio

detection and ranging.

BASIC PRINCIPLES

In essence, a radar consists of a transmitter and a receiver, each

connected to a directional antenna. The transmitter is capable of sending out a

large UHF or microwave power through the antenna. The receiver collects as

much energy as possible from the echoes reflected in its direction by the target

and then treats and displays this information in a suitable way. The receiving

antenna is very often the same as the transmitting antenna. This is

accomplished through a kind of time-division multiplexing arrangement, since

the radio energy is very often sent out in the form of pulses



FUNDAMENTALS

Basic radar system: The block diagram of an elementary pulsed radar set

is shown in Fig. For each transmitted pulse, the cycle of events is as follows.

Figure 1 Block diagram of an elementary pulse radar set

Figure 1 Block diagram of an elementary pulse radar set

In response to an internally generated trigger signal, the transmitter

generates a short, rectangular pulse. As soon as a small fraction of the pulse

power is fed to the duplexer, this device disconnects the receiver from the

antenna and connects the transmitter to it. In most radars, though by no

Dept of ECE VJEC,chemperi

Transmitter

Receiver

Duplexer

10


means in all, the antenna moves in a predetermined pattern, i.e., it scans.

Either way, it is normally directional and sends out the generated pulse

in the direction in which it is pointing at the time. The scanning speed may be

mechanically high, but it is small compared with the time taken by pulses to

return from a normal range of targets. Thus, when such echoes are received,

the antenna still points in the right direction to collect them.

As soon as the transmitted pulse terminates, the duplexer disconnects

the transmitter from the antenna. The duplexer also reconnects the receiver to

the antenna, allowing the returning echoes to be correctly processed. The

received pulses are amplified and demodulated by the receiver (which is

almost invariably super heterodyne, as had been discussed in detail in Chap.

6). The pulses from the returning echoes (and noise, of course) are then fed to

the device on which they are to be displayed, as will be described. The cycle is

complete, and the set is once again ready for the transmission of the next pulse

and the succeeding ones, while the antenna scans along its predetermined path.

The radar set is able to show the position of the target, because information

about the azimuth (horizontal direction) and the elevation (vertical direction)

of the antenna is available. In addition, the distance to the target may

transmitter output tubes, and the first stage of the receiver is often a diode

mixer. The antenna generally uses a parabolic reflector of some form, as will be

mentioned in Sec.



Development of radar From its inception, radar has used a system of

sending short, powerful pulses of radio energy and then analyzing the returned

echoes to determine the position, distance and possibly velocity of the target.

However, the methods of doing so have evolved and become far more refined

and sophisticated as time has gone by. The primary incentive as in so many

other things was the imminence of war. Radar was made possible by a

technology, which, at the time war broke out, was just beginning to show

promise. This technology itself took great strides forward to meet the new

challenges imposed by war.

The first radars worked at much lower frequencies than present systems

(as loq as 60MHz for the original British coastal air-warning radar because of a

lack of sufficiently powerful transmitting tubes at higher frequencies. This was

changed in 1940 with the appearance of the cavity magnetron, and the stage was

then set for the development of modern radar. As can be appreciated, one of the

prime requirements of a radar system is that it should have a fair degree of

accuracy in its indication of target direction. This is possible only if the

antennas used are narrow beam ones, i.e., have dimensions of several

wavelengths. That requirement cannot be fulfilled satisfactorily unless the

wavelengths themselves are fairly short, corresponding to the upper UHF or

microwave frequencies.



HARDWARE DESCRIPTION

The impulse radar bullet system developed in the International Research

Centre for Telecommunications-transmission and Radar (IRCTR). Impulse

radar bullet system comprises Impulse generator, Transmitter, Receiver,

Pulse extender, A/D converter, Processor and Visual display.

Block diagram

IMPULSE GENERATOR

The pulse generator delivered by SATIS Co. produces 0.8 ns

monocycle pulses. The unique feature of this generator is its small trailing

oscillations, which are below 2.4% of maximum amplitude during the first 2

ns and below 0.5% afterwards. The advantage of a monocycle in

comparison with a mono pulse is that the frequency spectrum of the first

one decreases to zero at low frequencies, which cannot be efficiently



transmitted via the antenna system, while the frequency spectrum of the

second one has a global maximum there. As a result, the magnitude of the

field radiated by an antenna system fed by a monocycle is considerably

larger than the magnitude of the field radiated by the antenna system fed by

a monopoles with the same magnitude.

output signal from the 0.8ns generator

The generator spectrum covers a wide frequency band from

500MHz till 2GHz on 3dB level. At frequencies below 1GHz, attenuation

losses in the ground are small and considerable penetration depth can be

achieved. However, landmines detection requires down-range resolution of

the order of several centimeters, which can be achieved using frequencies

above 1GHz. It was found experimentally that the 0.8ns monocycle satisfies

penetration and resolution requirements. This output signal from 0.8ns

generator is shown in figure. The spectrum of this pulse has a maximum at



frequencies where the attenuation losses in the ground start to increase. So

the spectral content of the monocycle below this maximum penetrates deep

into the ground and the spectral content above this maximum provides

sufficient down-range resolution.

ANTENNA SYSTEM

The antenna system is one of the most critical parts of radar bullet

system, because its performance depends strongly on the antenna system.

The antenna system should satisfy a number of demands. The antenna

system contains transmitter and receiver. The transmit antenna should:

Radiate short ultra-wide band (UWB) pulse with small ringing.

Radiate electro magnetic energy within a narrow cone in order to filter

out undesirable back scattering from surrounding objects.

Produce an optimal footprint on the ground surface and below it.

The waveform of the radiated field on the surface and in the ground

should be the same.

The waveform of the radiated field in the ground should not depend on

type of the ground.

The receiver antenna should:

Allow time windowing to isolate the direct air wave from the ground

reflection.

Provide sufficient sensitivity in order to receive very weak fields.



Receive the field in a local point; effective aperture should not be

larger than 1cm2.

Be elevated at least 10cm above the ground surface.

Additionally a possibility to measure simultaneously backscattered

field in two orthogonal polarizations is desirable.

PULSE EXTENDER

Pulse extender will amplify the ground reflection signal up to the

maximum level acquired by A/D converter.

A/D CONVERTER

The transmitter sends out a series of electromagnetic pulses then

listens with the receiver connected to high speed sampler which in turn

feeds A/D Converter. A dielectric anomaly in the soil may cause the signal

to be reflected back to a separate receiver antenna. This information is

converted from nanoseconds to milliseconds so that it may be digitized by a

conventional A/D converter for processing and display. The center

frequency and band width of the transmitted pulse can be varied by

changing the antenna and are chosen with respect to the required depth of

penetration, soil type and size of the object to be detected. In this

experiment, we used antennas with a center frequency 1.4GHz and 80%

band width. The precision of sampling converter is sufficiently high to do

accurate measurements of scattered transient field. This A/D converter 12



bit accuracy. This provides 66 dB linear dynamic ranges. A/D converter

converts the signal into digital signal which passes to the processor.

PROCESSOR

A/D converter converts the signal into digital signal which passes to

the processor. Processor filters the signal. This signal shows presence or

absence of surrogate mine in the soil. Processor allows passing the presence

of mine detecting signal. Processor selects the mine detecting signal and

passes to the visual display.

VISUAL DISPLAY

Visual display helps to see the range of targets. It displays the exact

position of landmine. The advent of the magnetron also made possible the next

steps in the evolution of radar, namely, airborne radar for the detection of

surface vessels and then airborne aircraft interception radar. In each of these,

particularly the former, tight beams are necessary to prevent the receiver from

begin swamped by ground reflections, which would happen if insufficient

discrimination between adjacent targets existed.

Microwave radar for antiaircraft fire control was quickly developed, of

which the most successful ground - based version was the U.S. Army's SCR-58.

It was capable of measuring the position of enemy aircraft to within 0.1 °, and

the distance, or range to within 25m. such radars were eventually capable of

tracking targets by locking onto them, with the aid of servomechanisms

controlling the orientation of the antennas. Anti-surface vessel (ASV) radars

became very common and quite accurate toward the end of the war. So aid



airborne radar for navigation, bombing or bomber protection electronic

navigation systems were also developed. Radar countermeasures were

instituted, consisting mainly of jamming (transmission of confusing signals at

enemy radar) or the some what more effective dropping of aluminum foil, in

strips of about a half - wavelength, to cover approaching aircraft by producing

false echoes. This "chaff"(American) or "window"(British) proved very

effective, but its use in the war was considerably delayed. Each side thought

that the other did not know about it and so it was kept secret; however, it

eventually came to be used on a very larges scale. One of the indications of the

enormous growth in the importance of radar in World War 11 is the increase in

the staff of the U.S Army’s Radiation Laboratory. It started with about 40

people in 1941, and number multiplied tenfold by 1945.

The advent of the magnetron also made possible the next steps in the evolution

of radar, namely, airborne radar for the detection of surface vessels and then

airborne aircraft interception radar. In each of these, particularly the former,

tight beams are necessary to prevent the receiver from begin swamped by

ground reflections, which would happen if insufficient discrimination between

adjacent targets existed. Microwave radar for antiaircraft fire control was

quickly developed, of which the most successful ground - based version was the

U.S. Army's SCR-58. It was capable of measuring the position of enemy aircraft

to within 0.1°, and the distance, or range to within 25m. Such radars were

eventually capable of tracking targets by locking onto them, with the aid of



servomechanisms controlling the orientation of the antennas. Anti-surface

vessel (ASV) radars became very common and quite accurate toward the end of

the war. So aid airborne radar for navigation, bombing or bomber protection

electronic navigation systems were also developed. Radar countermeasures

were instituted, consisting mainly of jamming (transmission of confusing

signals at enemy radar) or the some what more effective dropping of aluminum

foil, in strips of about a half - wavelength, to cover approaching aircraft by

producing false echoes. This "chaff"(American) or "window"(British) proved

very effective, but its use in the war was considerably delayed. Each side

thought that the other did not know about it and so it was kept secret; however,

it eventually came to be used on a very larges scale. One of the indications

of the enormous growth in the importance of radar in World War 11 is the

increase in the staff of the U.S. Army's Radiation Laboratory. It started with

about 40 people in 1941, and number multiplied tenfold by 1945.

The radar receiver is an ordinary radio receiver having the lowest

possible noise figure, high sensitivity, and a bandwidth appropriate for handling

the pulses involved. The receiver video output is usually displayed on a

cathode-ray tube indicator in such a manner as to show the time difference

between the outgoing pulses and the returning echoes. To achieve this result, the

sweep voltage of the cathode-ray-tube display is synchronized with the

transmitted pulses.



EXPERIMENTAL SET UP

Radar pulse spreads to a radius of 15 m.

First of all, a special bullet is fired downward into the ground from a gun

mounted on a helicopter flying about 100m above the ground. The bullet is

designed in such a way that it gives out powerful bust of radio waves from

under the ground. The bullet will produce a pulse of radio waves as it pierces

the ground, and the signal reflected from any landmines within about a 15m

radius will be detected by an antenna on the helicopter.



Once the mines are located, they can be destroyed at once or their exact

position noted so they can be destroyed at once or their exact position noted so

they can be dealt with later. And if the bullet hits it, it would explodeThe radar

pulse is generated from the bullets hit by a process known as magnetic flux

compression.



MAGNETIC FLUX COMPRESSION

Inside the bullet is a solid metal cylinder, surrounded by a tightly wound

coil of wire. As the bullet leaves the gun, there is a battery generating a

magnetic field in the cylinder. When the bullet smashes into the ground, the

sudden deceleration forces the cylinder out from inside the coil. The sudden

movement of the metal cylinder through the magnetic field induces a large pulse



of current in the coil. The coil then acts like an antenna, converting the pulse

into a short burst of high frequency radiation.

FIELD TEST

After the laboratory tests, testes were conducted at the Arizona desert

using the same experimental setup , the radar bullet was able to detect 35 anti-

tank mines and Val Mara 69 antipersonnel mines, which are a particular

problem in northern Iraq, where the mines have been laid by saddaam husseins

force in their confrontation with the KURBS.



ADVANTAGES

The light weight system can be fitted to any helicopter. i.e. the gun antenna

computer controllers etc.

Extremely small bullets can be used for detection. A 30 mm bullet gives out

a 4 KW radar pulse - almost 10 times more power than a standard ground

penetrating radar- from 20 centimeters down.

Also since the bullet is beneath the surface of the ground, it transmits more

radio wave into the ground. For ordinary ground, penetrating radar little

radiation penetrates the soil, most is reflected by the ground because of the

sudden change in density between the air and the soil.

It has accurate measurements.

It locates even small targets.

It has been well founded by the defense.

It operates by detecting the dielectric soils which allows it to locate even no

metallic mines.

Biological sensors can only operate for limited periods, but in GPR has no

such limits.

It has been tested in different environmental conditions.



DISADVANTAGES

Plastic landmines cannot be detected.

It is highly expensive.

It is more power hungry.

It can suffer falls alarm rates as high as metal detectors.



APPLICATIONS

1. It can be used for detecting landmines

2. It could help geologists surveying for oil, minerals and other buried natural

resources.

3. It can be used for detecting buried pipes. For e.g. recently an illegal pipeline

carrying drugs between Afghanistan and Turkmenistan have been

discovered. Such type of illegal pipeline can be found out using radar

bullets.



FUTURE PROSPECTS

1. As the UN has already implemented a world wide ban on antipersonnel

mines, the invention of radar bullet helps to speed up the destruction of the

mines.

2. Ten thousands of antipersonnel mines lied buried in the hilly regions of

Cambodia, n. Korea, Afghanistan etc. and according to UN it would take

more than 100 years to detect and destroy these if worked out manually.

Mines clearance or defining is normally broken into these stages. Detection

removal and disposal. Current detection methods range from high-tech

electronic (ground penetrating radar), infrared, magnetic resonance imaging)

to biological detection schemes(Dog Sniff or) and insects or bacteria to

simple brute force detonation methods (Flails, Rollers and plows) and the

use of the hand held mechanical prodders. Most of these methods are very

slow and or expensive and suffer from a hi8gh false alarm rate .So with

helicopters and radar bullets, the mines can be cleared easily.

3. Mass graveyards which results from internal civil wars as in

Cambodia, Kosovo and in some African nations can be detected using radar

bullets.



MINE EFFECTED COUNTRIES

The countries known to have severe landmine problems are;

Afghanistan, Bosnia, Eritrea, Croatia, china. Unfortunately India Pakistan, Sri

Lanka, Myanmar are also in the list of less-mine affected countries b-sides other

100 countries.



CONCLUSION

The research on radar bullet were headed by the electrical engineers.

Themes Engel of William Nunnally at the university of Missouri at

Columbia, with $5million in funding from the US army. This can be used

not only for detecting antipersonnel mines, but also for detecting anti- tank

mines as well as for the mines used in sea for targeting the ship and

submarines. . Since it can also be used for exploring oil, minerals and other

buried natural resources, the discovery of radar bullet is a big boost for the

modern world as we are in 21St century. Currently, very little technology is

used in real-world defining activities. Active programs by the U.S Army in

both land mine detection sensor development and systems integration are

evaluating new technologies, incrementally improving existing

technologies, increasing the probability of detection, reducing the false

alarm rate, and planning out useable deployment scenarios. Through

iterative design, build test cycles, and blind and scored testing at Army mine

lanes, steady progress is being made.



REFERENCE

1. Radar and radio detection- Fredrick Emmons Terman 2. Landmines and radio

detecting- Andrew Deerorow 3. Armed forces - nic.in


http://nic.in/

radar bullet

Documents

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abstract radar bullet

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