Radar Bullet Seminar Report 3w2d3k
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 1
INTRODUCTION Radar bullet is a relatively new discovery that was invented in the US. It was developed by International Research Centre for Telecommunications-Transmission and RADAR (IRCTR). It is used for detecting land mines. And this discovery finds a very important prospect as about 139 countries signed a treaty in favor of banning antipersonal 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 at 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. The countries known to have severe landmine problems are Afghanistan, Bosnia, Cambodia, Ethiopia, Vietnam, Iraq, Kuwait, Laos, Egypt, Eritrea, Chevalier, China. Unfortunately India, Pakistan, Srilanka, Myanmar are in the list of less mine affected countries besides other 100 countries.
Dept of ECE, VIT
Page 1
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 2
LAND MINE The purpose of a landmine is to disable, immobilize or kill. It is an explosive device activated either by a person or vehicle or by command detonated by electric wire or radio signals. Most land mines are laid on just below the surface of ground and are activated by pressure or trip-wire. Usually most of the landmines will contain many metallic parts, which can be made use of in their detection. Anti-personal mines claims 70 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 traumas that follow the blast- means these children will have to be looked after for many years.
Fig 2.1: Anti-Personnel Landmine
Fig 2.2:Anti-Tank Landmine Dept of ECE, VIT
Page 2
Landmine Detection using RADAR BULLET 2014-2015 Landmines In this discussion we deal with buried anti-tank (AT) and antipersonnel (AP) landmines which require close approach or 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 A child injured at the age of 10 will need about 25 critical limbs during there life time. This cost in 3000 Dollars a huge sum to pay in countries where people earn as little as 10 dollar a month. . Between 1979 of 1996 the red crores fitted over 70,000 Amputees with critical limbs and the land mine problem in still growing. There for considering these factors the discovery of radar bullet is really a big boost to our world as we launches to 21st century.
Dept of ECE, VIT
Page 3
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 3
PRINCIPLES USED TO DETECT LANDMINES 1. Metal detection 2. Explosive detection
3.1. Metal Detection Essentially the two most common components of landmines are metals and explosives. Manufactured mines have casting made from a variety of materials including wood, metals, Plastic metal or other synthetic materials. From the detection standpoint, metal is the easier component to detect.
Fig 3.1: Metal Detection Metal detectors (commonly referred to as mine detectors) are now capable of signaling the presence of minute piece of metal. However some mines are metal free on certain virtually non-metal. These non-metals challenge the capacity of current metal detectors.
4.2. Explosive Detection The explosives are one common ingredient that is found in all mines. Detecting explosives however is a complicated process. Modem airports have explosive detecters, which can detect small traces of explosives in suitcases and other containers. Locating traces or the order of explosives is an open field demands technology that can operate in Dept of ECE, VIT
Page 4
Landmine Detection using RADAR BULLET 2014-2015 an unlimited variety of environmental conditions that are subjected to wind, water and soil changes and variations. Explosive detection under field conditions has recently become the preview of mine detection dogs. A dog’s nose has proven to be a very sophisticated and reliable sensor, however handling maid detection dog teams and ensuring consistent behaviour in varied hazard scenarios is a complicated and demanding tasks.
Fig 3.2: Explosive Detection In all the above said methods mine detection in conducted in close proximity. That is detection is conducted after going very near to the mine. This method can prove to be dangerous in many occations. So it is not considered to be the safest method. A preferred method is to use detection devices that locate land mines at a safe distance from the deminer. Using detection devices that pinpoint land mines exploded from a distance either overhead on at ground level in the best possible way to determine the actual location of individual land mines. Ones the threat is located, that is mines are pin pointed, we can deactivate it safely. This is where the importance of mine detection using radar bullet comes.
Dept of ECE, VIT
Page 5
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 4
RADAR BULLET The radar bullet is a special type of bullet. The main use of radar bullet is to find landmines without setting foot on the ground. This consists of firing a special bullet in to the ground from a helicopter, which could pin point buried land mines. The bullet units a radar pulse as it grounds to a 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. Landmines In this discussion we deal with buried anti-tank (AT) and anti-personnel (AP) landmines which require close approach or 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. Inside the bullet is a metal cylinder, surrounded by a tightly wounded coin of wire. As the bullet leaves the gun, there is a battery generating a magnetic field in the cylinder. Battery
bullet casing
Metallic cylinder
Fig 4: Radar Bullet
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 5
RADAR PRINCIPLE Radar is Radio detection and ranging. Radar is a sensor. Radar makes use of radio waves to detect and locate objects. The purpose is to provide estimates of certain characteristics of its surroundings most commonly the presence, position and motion of aircrafts, ships and other vehicles. Radar operates by transmitting electro magnetic energy into the surroundings and detecting energy reflected by object. If a narrow beam of this energy is transmitted by the directive antenna, the direction from which reflections come and hence the bearing of object may be estimated. .The distance to the reflecting object in estimated by measuring the period between the transmission of radar pulse and reception of echo. In radar bullet principle the change of medium by the waves must be taken into consideration.
Fig 5: Principle of RADAR Radars have generally from principal parts, the transmitter antenna receiver, and display. The transmitter will transmit an electro magnetic signal through the antenna, Dept of ECE, VIT
Page 7
Landmine Detection using RADAR BULLET 2014-2015 which will hit the target and reflects back. The same antenna and the time difference between the signal transmission and reception is calculated, which will help up to measure the distance of the target from the radar.
5.1Fundamentals
Transmitter
Duplexer
Receiver
Fig 5.1: Block diagram of an elementary pulse radar set
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 se 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 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 Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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. 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.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
5.2 CALCULATIONS
R OBJECT RADAR
Fig 5.2: calculations of Parameters T
=time b/w signal transmission and reception.
2R
= Total distance traveled.
c
= Velocity of electromagnetic signals = 3*108 m/sec.
Velocity = distance / time i.e.; C
= 2R / T Or
R
=CT /2
So in the screen an obstacle will be shown at a distance R from the radar.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 6
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.
Fig 6: 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 Dept of ECE, VIT
Page 11
Landmine Detection using RADAR BULLET 2014-2015 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.
Fig 6.1: 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: Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
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 Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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 es to the processor.
PROCESSOR A/D converter converts the signal into digital signal which es to the processor. Processor filters the signal. This signal shows presence or absence of surrogate mine in the soil. Processor allows ing the presence of mine detecting signal. Processor selects the mine detecting signal and es 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. Antisurface 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 somewhat 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 large scale.
One
of the indications of the enormous growth in the importance of radar in World War 11 is Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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. Antisurface 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 somewhat 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 large 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.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 7
EXPERIMENTAL SETUP First of all a special bullet in fired downward into the ground , from a gun mounted on a helicopter flying about 100 m above the ground. The bullet in designed in such a way that it gives out powerful blast of radio waves from under the ground. The bullet will produce a pulse of radio waves as it pierces the ground and signal is reflected from any landmines within about a 15 meter radius will be detected by an antenna on the helicopter. Once the mines are located they can be destroyed at once or there exact position are noted so they can be destroyed at once on their exact positions are noted so that can be diploid later. And if the bullet hits it, it would explode. The Radar pulse is generated from the bullets kinetic energy by a process known as, “Magnetic flux compression.”
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
Fig 7: Experimental Setup
CHAPTER 8
MAGNETIC FLUX COMPRESSION Inside the bullet is a metal cylinder, surrounded by a tightly wounded coin 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 thus acts like an antenna converting the pulse into a short burst of high frequency radiation.
Fig 8: Magnetic Flux Compression Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 9
FIELD TESTS After the laboratory tests, tests where conducted at the Arizona desert. Using the same experiment set up, the radar bullet as able to detect 35 cm anti tank mines and Val Mara 69 anti personal mines, which are a particular problem in northern Iraq, where the mines have been laid by Saddam Hussein’s forces in their confrontation with the Kurds
9.1. ADVANTAGES
The light weight system can be fitted to any helicopter ie; gun, computer controls etc.
Extremely small bullets can be used for detection A 30 mm bullet gives out a 4 kW radar pulse. Almost 10 times move power than a standard ground penetrating radar from 20cm down.
Also since the bullet is beneath the surface of the ground, it transmits more radio wave into the ground. For ordinary 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. Here the radiation has to change the medium twice. First from air to ground, and then after reflection, from ground into air. Therefore weak signals are obtained. But in radar bullet principle the radiation has to change the medium only once i.e.; from the ground into the air and hence stronger signals are obtained.
9.2. DISADVANTAGES
It cannot detect plastic land mines, but researches are working hard to overcome this.
Since the equipment is to be mounted on a helicopter, the cost of operation is higher. But considering its future prospects and the static’s released by red –Cross, cost can never be considered as a disadvantage.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
9.3. APPLICATIONS
It can be used for detecting land mines.
It can be used for detecting buried pipelines .For example: - Recently an illegal pipeline carrying drugs between Afghanistan and Turkmistan has been discovered. Such type of illegal pipelines can be detected out by using radar bullet.
This can be applied in future space travels when we go to a different planet. In that case, we can shoot this bullet in to the ground and detect mineral and other deposits.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
FUTURE PROSPECTS As the UN has already implemented a worldwide ban on anti-personal mines. The invention of radar bullet helps to speed up the destruction of mines. Ten thousands of anti - personal mines lied buried in the hilly regions of Cambodia / north - Korea / Afghanistan etc. And according to UN it would more than 100 years to detect and destroy these, if worked
take
out manually. Mine
clearance or demining is normally broken into three 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 snuffers and insect or bacteria ) to simple brute forces detection methods (Rails, Rollers and plows) and use of hand-held mechanical plodders .Most of these methods are very slow and/or expensive and suffer from a high false alarm rate. So with helicopter and radar bullet, the mines can be cleared easily. Mass graveyards which result from internal civil wars as in Combodia, Kosoro and in same African nations can be detected using radar bullets. This can be applied is future space travels, when we go to a different planet, in that case we can shoot this bullet in to the ground and detect mineral deposits and other deposits.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CONCLUSION Mines are major cause of concern in many countries. Detection and removal of mines is very important as it is hazardous to both man and animals alike. The conventional methods that are being used right now for mine detection involves working in close proximity for the mines. So overall mine detection using radar bullets is a cutting edge technology that is safe and effective. With all its advantages it may be hoped that mine detection using radar bullets will be more used in detection of mine there by making the world safer place to live in.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
REFERENCES 1. S.VITEBSKIY AND L.CARIN “ Late –time resonant frequencies buried bodies of revolution” 2. L.CARIN, R KAPOOR, C.E BAVAM. “Polarimatic SAR imaging of buried land mines” 3. MERILL .1. SKOLNIK. Tata MC Grawhill
Dept of ECE, VIT
Page 22
CHAPTER 1
INTRODUCTION Radar bullet is a relatively new discovery that was invented in the US. It was developed by International Research Centre for Telecommunications-Transmission and RADAR (IRCTR). It is used for detecting land mines. And this discovery finds a very important prospect as about 139 countries signed a treaty in favor of banning antipersonal 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 at 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. The countries known to have severe landmine problems are Afghanistan, Bosnia, Cambodia, Ethiopia, Vietnam, Iraq, Kuwait, Laos, Egypt, Eritrea, Chevalier, China. Unfortunately India, Pakistan, Srilanka, Myanmar are in the list of less mine affected countries besides other 100 countries.
Dept of ECE, VIT
Page 1
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 2
LAND MINE The purpose of a landmine is to disable, immobilize or kill. It is an explosive device activated either by a person or vehicle or by command detonated by electric wire or radio signals. Most land mines are laid on just below the surface of ground and are activated by pressure or trip-wire. Usually most of the landmines will contain many metallic parts, which can be made use of in their detection. Anti-personal mines claims 70 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 traumas that follow the blast- means these children will have to be looked after for many years.
Fig 2.1: Anti-Personnel Landmine
Fig 2.2:Anti-Tank Landmine Dept of ECE, VIT
Page 2
Landmine Detection using RADAR BULLET 2014-2015 Landmines In this discussion we deal with buried anti-tank (AT) and antipersonnel (AP) landmines which require close approach or 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 A child injured at the age of 10 will need about 25 critical limbs during there life time. This cost in 3000 Dollars a huge sum to pay in countries where people earn as little as 10 dollar a month. . Between 1979 of 1996 the red crores fitted over 70,000 Amputees with critical limbs and the land mine problem in still growing. There for considering these factors the discovery of radar bullet is really a big boost to our world as we launches to 21st century.
Dept of ECE, VIT
Page 3
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 3
PRINCIPLES USED TO DETECT LANDMINES 1. Metal detection 2. Explosive detection
3.1. Metal Detection Essentially the two most common components of landmines are metals and explosives. Manufactured mines have casting made from a variety of materials including wood, metals, Plastic metal or other synthetic materials. From the detection standpoint, metal is the easier component to detect.
Fig 3.1: Metal Detection Metal detectors (commonly referred to as mine detectors) are now capable of signaling the presence of minute piece of metal. However some mines are metal free on certain virtually non-metal. These non-metals challenge the capacity of current metal detectors.
4.2. Explosive Detection The explosives are one common ingredient that is found in all mines. Detecting explosives however is a complicated process. Modem airports have explosive detecters, which can detect small traces of explosives in suitcases and other containers. Locating traces or the order of explosives is an open field demands technology that can operate in Dept of ECE, VIT
Page 4
Landmine Detection using RADAR BULLET 2014-2015 an unlimited variety of environmental conditions that are subjected to wind, water and soil changes and variations. Explosive detection under field conditions has recently become the preview of mine detection dogs. A dog’s nose has proven to be a very sophisticated and reliable sensor, however handling maid detection dog teams and ensuring consistent behaviour in varied hazard scenarios is a complicated and demanding tasks.
Fig 3.2: Explosive Detection In all the above said methods mine detection in conducted in close proximity. That is detection is conducted after going very near to the mine. This method can prove to be dangerous in many occations. So it is not considered to be the safest method. A preferred method is to use detection devices that locate land mines at a safe distance from the deminer. Using detection devices that pinpoint land mines exploded from a distance either overhead on at ground level in the best possible way to determine the actual location of individual land mines. Ones the threat is located, that is mines are pin pointed, we can deactivate it safely. This is where the importance of mine detection using radar bullet comes.
Dept of ECE, VIT
Page 5
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 4
RADAR BULLET The radar bullet is a special type of bullet. The main use of radar bullet is to find landmines without setting foot on the ground. This consists of firing a special bullet in to the ground from a helicopter, which could pin point buried land mines. The bullet units a radar pulse as it grounds to a 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. Landmines In this discussion we deal with buried anti-tank (AT) and anti-personnel (AP) landmines which require close approach or 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. Inside the bullet is a metal cylinder, surrounded by a tightly wounded coin of wire. As the bullet leaves the gun, there is a battery generating a magnetic field in the cylinder. Battery
bullet casing
Metallic cylinder
Fig 4: Radar Bullet
Dept of ECE, VIT
Page 6
Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 5
RADAR PRINCIPLE Radar is Radio detection and ranging. Radar is a sensor. Radar makes use of radio waves to detect and locate objects. The purpose is to provide estimates of certain characteristics of its surroundings most commonly the presence, position and motion of aircrafts, ships and other vehicles. Radar operates by transmitting electro magnetic energy into the surroundings and detecting energy reflected by object. If a narrow beam of this energy is transmitted by the directive antenna, the direction from which reflections come and hence the bearing of object may be estimated. .The distance to the reflecting object in estimated by measuring the period between the transmission of radar pulse and reception of echo. In radar bullet principle the change of medium by the waves must be taken into consideration.
Fig 5: Principle of RADAR Radars have generally from principal parts, the transmitter antenna receiver, and display. The transmitter will transmit an electro magnetic signal through the antenna, Dept of ECE, VIT
Page 7
Landmine Detection using RADAR BULLET 2014-2015 which will hit the target and reflects back. The same antenna and the time difference between the signal transmission and reception is calculated, which will help up to measure the distance of the target from the radar.
5.1Fundamentals
Transmitter
Duplexer
Receiver
Fig 5.1: Block diagram of an elementary pulse radar set
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 se 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 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 Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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. 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.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
5.2 CALCULATIONS
R OBJECT RADAR
Fig 5.2: calculations of Parameters T
=time b/w signal transmission and reception.
2R
= Total distance traveled.
c
= Velocity of electromagnetic signals = 3*108 m/sec.
Velocity = distance / time i.e.; C
= 2R / T Or
R
=CT /2
So in the screen an obstacle will be shown at a distance R from the radar.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 6
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.
Fig 6: 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 Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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.
Fig 6.1: 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: Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
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 Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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 es to the processor.
PROCESSOR A/D converter converts the signal into digital signal which es to the processor. Processor filters the signal. This signal shows presence or absence of surrogate mine in the soil. Processor allows ing the presence of mine detecting signal. Processor selects the mine detecting signal and es 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. Antisurface 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 somewhat 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 large scale.
One
of the indications of the enormous growth in the importance of radar in World War 11 is Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015 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. Antisurface 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 somewhat 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 large 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.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 7
EXPERIMENTAL SETUP First of all a special bullet in fired downward into the ground , from a gun mounted on a helicopter flying about 100 m above the ground. The bullet in designed in such a way that it gives out powerful blast of radio waves from under the ground. The bullet will produce a pulse of radio waves as it pierces the ground and signal is reflected from any landmines within about a 15 meter radius will be detected by an antenna on the helicopter. Once the mines are located they can be destroyed at once or there exact position are noted so they can be destroyed at once on their exact positions are noted so that can be diploid later. And if the bullet hits it, it would explode. The Radar pulse is generated from the bullets kinetic energy by a process known as, “Magnetic flux compression.”
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
Fig 7: Experimental Setup
CHAPTER 8
MAGNETIC FLUX COMPRESSION Inside the bullet is a metal cylinder, surrounded by a tightly wounded coin 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 thus acts like an antenna converting the pulse into a short burst of high frequency radiation.
Fig 8: Magnetic Flux Compression Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CHAPTER 9
FIELD TESTS After the laboratory tests, tests where conducted at the Arizona desert. Using the same experiment set up, the radar bullet as able to detect 35 cm anti tank mines and Val Mara 69 anti personal mines, which are a particular problem in northern Iraq, where the mines have been laid by Saddam Hussein’s forces in their confrontation with the Kurds
9.1. ADVANTAGES
The light weight system can be fitted to any helicopter ie; gun, computer controls etc.
Extremely small bullets can be used for detection A 30 mm bullet gives out a 4 kW radar pulse. Almost 10 times move power than a standard ground penetrating radar from 20cm down.
Also since the bullet is beneath the surface of the ground, it transmits more radio wave into the ground. For ordinary 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. Here the radiation has to change the medium twice. First from air to ground, and then after reflection, from ground into air. Therefore weak signals are obtained. But in radar bullet principle the radiation has to change the medium only once i.e.; from the ground into the air and hence stronger signals are obtained.
9.2. DISADVANTAGES
It cannot detect plastic land mines, but researches are working hard to overcome this.
Since the equipment is to be mounted on a helicopter, the cost of operation is higher. But considering its future prospects and the static’s released by red –Cross, cost can never be considered as a disadvantage.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
9.3. APPLICATIONS
It can be used for detecting land mines.
It can be used for detecting buried pipelines .For example: - Recently an illegal pipeline carrying drugs between Afghanistan and Turkmistan has been discovered. Such type of illegal pipelines can be detected out by using radar bullet.
This can be applied in future space travels when we go to a different planet. In that case, we can shoot this bullet in to the ground and detect mineral and other deposits.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
FUTURE PROSPECTS As the UN has already implemented a worldwide ban on anti-personal mines. The invention of radar bullet helps to speed up the destruction of mines. Ten thousands of anti - personal mines lied buried in the hilly regions of Cambodia / north - Korea / Afghanistan etc. And according to UN it would more than 100 years to detect and destroy these, if worked
take
out manually. Mine
clearance or demining is normally broken into three 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 snuffers and insect or bacteria ) to simple brute forces detection methods (Rails, Rollers and plows) and use of hand-held mechanical plodders .Most of these methods are very slow and/or expensive and suffer from a high false alarm rate. So with helicopter and radar bullet, the mines can be cleared easily. Mass graveyards which result from internal civil wars as in Combodia, Kosoro and in same African nations can be detected using radar bullets. This can be applied is future space travels, when we go to a different planet, in that case we can shoot this bullet in to the ground and detect mineral deposits and other deposits.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
CONCLUSION Mines are major cause of concern in many countries. Detection and removal of mines is very important as it is hazardous to both man and animals alike. The conventional methods that are being used right now for mine detection involves working in close proximity for the mines. So overall mine detection using radar bullets is a cutting edge technology that is safe and effective. With all its advantages it may be hoped that mine detection using radar bullets will be more used in detection of mine there by making the world safer place to live in.
Dept of ECE, VIT
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Landmine Detection using RADAR BULLET 2014-2015
REFERENCES 1. S.VITEBSKIY AND L.CARIN “ Late –time resonant frequencies buried bodies of revolution” 2. L.CARIN, R KAPOOR, C.E BAVAM. “Polarimatic SAR imaging of buried land mines” 3. MERILL .1. SKOLNIK. Tata MC Grawhill
Dept of ECE, VIT
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