Radar Bullet

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<p>Radar bullet</p> <p>seminar 2011</p> <p>RADAR BULLET</p> <p>Dept of ECE</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>ABSTRACT</p> <p>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</p> <p>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.</p> <p>Dept of ECE</p> <p>2</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>CONTENTS</p> <p> INTRODUCTION ABOUT RADAR BULLET PRINCIPLES EXPERIMENTAL SET UP MAGNETIC FLUX COMPRESSION FIELD TEST ADVANTAGE DISADVANTAGE APPLICATION FUTURE PROSPECTS CONCLUSION</p> <p>Dept of ECE</p> <p>3</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>INTRODUCTION</p> <p>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.</p> <p>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</p> <p>psychological trauma that follow the blast mean these children will have to be looked after for many year.</p> <p>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.</p> <p>Dept of ECE</p> <p>4</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>Technologies are used for landmine detection are:</p> <p>Metal detectors--- capable of finding even low-metal content mines in</p> <p>mineralized soils.</p> <p>Nuclear magnetic resonance, fast neutron activation and thermal</p> <p>neutron activation.</p> <p>Thermal imaging and electro-optical sensors--- detect evidence of</p> <p>buried objects.</p> <p>Biological sensors such as dogs, pigs, bees and birds. Chemical sensors such as thermal fluorescence--- detect airborne and</p> <p>waterborne presence of explosive vapors.</p> <p>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.</p> <p>Dept of ECE</p> <p>5</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>ABOUT RADAR BULLETRadar 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</p> <p>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</p> <p>Dept of ECE</p> <p>6</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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.</p> <p>In this discussion we deal with buried anti-tank (AT) and antipersonnel (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.</p> <p>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</p> <p>Dept of ECE</p> <p>7</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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</p> <p>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.</p> <p>Dept of ECE</p> <p>8</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>PRINCIPLES</p> <p>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.</p> <p>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.</p> <p>Dept of ECE</p> <p>9</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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.</p> <p>BASIC PRINCIPLESIn 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</p> <p>Dept of ECE</p> <p>10</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>FUNDAMENTALSBasic 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</p> <p>Transmitter</p> <p>Duplexer</p> <p>Receiver</p> <p>Figure 1 Block diagram of an elementary pulse radar set</p> <p>Dept of ECE</p> <p>11</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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</p> <p>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.</p> <p>The radar set is able to show the position of the target, because information about the azimuth (horizontal direction) and the elevation (vertical direction)</p> <p>Dept of ECE</p> <p>12</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>of the antenna is available.</p> <p>In addition, the distance to the target may</p> <p>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.</p> <p>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</p> <p>Dept of ECE</p> <p>13</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>requirement cannot be fulfilled satisfactorily unless the wavelengths themselves are fairly short, corresponding to the upper UHF or microwave frequencies.</p> <p>HARDWARE DESCRIPTION</p> <p>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.</p> <p>Block diagram</p> <p>IMPULSE GENERATORThe pulse generator delivered by SATIS Co. produces 0.8 ns monocycle pulses. The unique feature of this generator is its small trailingDept of ECE 14 VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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.</p> <p>output signal from the 0.8ns generator</p> <p>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</p> <p>Dept of ECE</p> <p>15</p> <p>VJEC,chemperi</p> <p>Radar bullet</p> <p>seminar 2011</p> <p>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.</p> <p>ANTENNA SYSTEMThe antenna system is on...</p>