FUTURE INSTITUTE OF ENGG. AND MGMT.

NAME: AKHTER RAAZROLL: 06/ECE/74REG. No.: 148010311066ROLL No.: 14803061047

LASER GUIDED MISSILE

TAB

LE O

F CO

NTEN

T

•INTRODUCTION

•WHAT IS LASER

•LGB

•HISTORY

•DEVELOPMENT

•RAW MATERIALS

•DESIGN

•THE MANUFACTURING PROCESS

•VARIOUS TYPES OF LGB

TAB

LE O

F CO

NTEN

T

•QUALITY CONTROL

•HOW TO USE THE MISSILE

•BYPRODUCTS/WASTE

•MODERN LASER GUIDED MISSILE

•THE FUTURE

•REFERENCES

INTRODUCTION

Missiles differ from rockets by virtue of a guidance system that steers them towards a pre-selected target. Unguided, or free-flight, rockets proved to be useful yet frequently inaccurate weapons when fired from aircraft during the World War II. This inaccuracy, often resulting in the need to fire many rockets to hit a single target, led to the search for a means to guide the rocket towards its target. The concurrent explosion of radio-wave technology (such as radar and radio detection devices) provided the first solution to this problem. Several warring nations, including the United States, Germany and Great Britain, mated existing rocket technology with new radio- or radar-based guidance systems to create the world's first guided missiles. Although these missiles were not deployed in large enough

numbers to radically divert the course of the World War II,

INTRODUCTION

Dr. Theodore Maiman built the first laser (Light Amplification by Stimulated Emission of Radiation) at Hughes Research Laboratories in 1960. The military realized the potential applications for lasers almost as soon as their first beams cut through the air. Laser guided projectiles underwent their baptism of fire in the extended series of air raids that highlighted the American effort in the Vietnam War. The accuracy of these weapons earned them the well-known sobriquet of "smart weapons." But even this new generation of advanced weaponry could not bring victory to U.S. forces in this bitter and costly war. However, the combination of experience gained in Vietnam, refinements in laser technology, and similar advances in electronics and computers, led to more sophisticated and deadly laser guided missiles. They finally received widespread use in Operation Desert Storm, where their accuracy and reliability played a crucial role in the decisive defeat of Iraq's military forces. Thus, the laser guided missile has established itself as a key component in today's high-tech military technology.

WHAT IS LASER

A laser is a device that emits light (electromagnetic radiation) through a process called stimulated emission. The term laser is an acronym for light amplification by stimulated emission of radiation.[1][2] Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses. Typically, lasers are thought of as emitting light with a narrow wavelength spectrum ("monochromatic" light). This is not true of all lasers, however: some emit light with a broad spectrum, while others emit light at multiple distinct wavelengths simultaneously. The coherence of typical laser emission is distinctive. Most other light sources emit incoherent light, which has a phase that varies randomly with time and position.

LGB(Laser Guided Missile)

Laser-guided missiles work by following the reflected light of a laser beam, which can either be shone on the target by the aircraft itself, by another airplane, or by ground troops with a handheld laser designator. Therefore, once the missile has been launched its own instrumentation is able to remain on target, rather than older laser-guided missiles that required the pilot to continually sight the target with the laser. Laser-guided missiles are used for those targets that need pinpoint accuracy. A disadvantage of laser-guided missiles is that their guidance systems do not work well in all weather conditions. If it is cloudy, the water droplets in the air cause the laser to diffract. Because the laser only operates within a certain bandwidth, the laser can be completely diffracted if it is too cloudy and the missile will not be able to locate its target. Rain has a similar effect on the laser because each raindrop serves to diffract the laser beam, once again deterring the missile from its target.

HISTORY Laser-guided missiles were first

developed during the Vietnam War. The Army began to research laser guidance systems in 1962. The first laser-guided bomb, the BOLT-117, was developed by the Air Force in 1967; however, it was not used in combat until 1968. The BOLT-117 worked using two planes. One plane was used to keep a laser illuminating the intended target, while the other’s job was to drop the missile by following the reflected laser bean and directing the missile by sending signals to its control fins. For high efficiency, there was a very narrow region within which the pilot could release the missile. Laser-guided missiles of this time were generally made of standard iron and were simply dumb bombs with a laser guidance and control system attached. They commonly had a range of three to four kilometers

DEVELOPMENT

A lthough the bomb may appear simple in design today -- bolt a guidance seeker on the front and control fins on the rear of  a standard bomb casing -- in the fall of 1965 it was anything but easy. Word and his fellow engineers . identified the problems they would have to conquer in a short time.  First, the team had to develop and build a seeker which would sense the laser light, and then figure a way to move that information to the Shrike control unit bolted on the end of the bomb.  Finally, they had to make it fly -- the bomb had to be aerodynamic Most of the work was adapting and improving missile technology, but Tom Weaver remembered one of the most significant challenges the TI team faced was electronically moving the guidance data from the seeker to the control unit in an era of  transistors and circuit breadboards.

DEVELOPMENT The team finally locked in 10 pulses per

second as the golden number for a bomb to guide to the target.     Working out of TI's labs in Dallas, Texas, and trudging down to the steamy, jungle like ranges of Eglin Air Force Base, Florida, the team set about to make laser guided bombs a reality in September 1965.  With only six months to design, test and prove laser guidance, the pressure of the ticking clock brought on a fast paced, sometimes unorthodox development cycle for the guided bomb. The TI engineers didn't know how to use a laser, having never seen a working model. Salonimer loaned them a laser, one of only two in the world, and they used the water tower in Plano, Texas as a fixed object to measure laser light return.

RAW MATERIALS

A laser guided missile consists of four important components, each of which contains different raw materials. These four components are the missile body, the guidance system(also called the laser and electronics suite), the propellant, and the warhead. The missile body is made from steel alloys or high-strength aluminum alloys that are often coated with chromium along the cavity of the body in order to protect against the excessive pressures and heat that accompany a missile launch. The guidance system contains various types of materials—some basic, others high-tech—that are designed to give maximum guidance capabilities. These materials include a photo detecting sensor and optical filters, with which the missile can interpret laser wavelengths sent from a parent aircraft. The photo detecting sensor's most important part is its sensing dome, which can be made of glass, quartz, and/or silicon. A missile's electronics suite can contain gallium-arsenide semiconductors, but some suites still rely exclusively on copper or silver wiring. Guided missiles use nitrogen-based solid propellants as their fuel source. Certain additives (such as graphite or nitroglycerine) can be included to alter the performance of the propellant. The missile's warhead can contain highly explosive nitrogen-based mixtures, fuel-air explosives (FAE), or phosphorous compounds. The warhead is typically encased in steel, but aluminum alloys are sometimes used as a substitute.

DESIGN

Two basic types of laser guided missiles exist on the modern battlefield. The first type "reads" the laser light emitted from the launching aircraft/helicopter. The missile's electronic suite issues commands to the fins (called control surfaces) on its body in an effort to keep it on course with the laser beam. This type of missile is called a beam rider as it tends to ride the laser beam towards its target. The second type of missile uses on-board sensors to pick up laser light reflected from the target. The aircraft/helicopter pilot selects a target, hits the target with a laser beam shot from a target designator, and then launches the missile. The missile's sensor measures the error between its flight path and the path of the reflected light. Correction messages are then passed on to the missile's control surfaces via the electronics suite, steering the missile onto its target.

DESIGN Regardless of type, the missile designer must run computer

simulations as the first step of the design process. These simulations assist the designer in choosing the proper laser type, body length, nozzle configurations, cavity size, warhead type, propellant mass, and control surfaces. The designer then puts together a package containing all relevant engineering calculations, including those generated by computer simulations. The electronics suite is then designed around the capabilities of the laser and control surfaces. Drawings and schematics of all components can now be completed; CAD/CAM .(Computer-Aided Design/Manufacture) technology has proven helpful with this task. Electronics systems are then designed around the capabilities of the aircraft's laser and the missile's control surfaces. The following step consists of generating the necessary schematic drawings for the chosen electronics system. Another computer-assisted study of the total guided missile system constitutes the final step of the design process

THE MANUFACTURING PROCESS

THIS PROCESS IS DONE BY 4 PARTS. THOSE ARE FOLLOWING……….

Constructing the body and attaching the fins

Casting the propellant

Assembling the guidance system

Final assembly

Constructing the body and attaching the fins

1 The steel or aluminum body is die cast in halves. Die casting involves pouring molten metal into a steel die of the desired shape and letting the metal harden. As it cools, the metal assumes the same shape as the die. At this time, an optional chromium coating can be applied to the interior surfaces of the halves that correspond to a completed missile's cavity. The halves are then welded together, and nozzles are added at the tail end of the body after it has been welded.

2 Moveable fins are now added at predetermined points along the missile body. The fins can be attached to mechanical joints that are then welded to the outside of the body, or they can be inserted into recesses purposely milled into the body.

Casting the propellant The propellant must be carefully applied to the

missile cavity in order to ensure a uniform coating, as any irregularities will result in an unreliable burning rate, which in turn detracts from the performance of the missile. The best means of achieving a uniform coating is to apply the propellant by using centrifugal force. This application, called casting, is done in an industrial centrifuge that is well-shielded and situated in an isolated location as a precaution against fire or

explosion.

Assembling the guidance system

The principal laser components—the photo detecting sensor and optical filters—are assembled in a series of operations that are separate from the rest of the missile's construction. Circuits that support the laser system are then soldered onto pre-printed boards; extra attention is given to optical materials at this time to protect them from excessive heat, as this can alter the wavelength of light that the missile will be able to detect. The assembled laser subsystem is now set aside pending final assembly. The circuit boards for the electronics suite are also assembled independently from the rest of the missile. If called for by the design, microchips are added to the boards at this time.

The guidance system (laser components plus the electronics suite) can now be integrated by linking the requisite circuit boards and inserting the entire assembly into the missile body through an access panel. The missile's control surfaces are then linked with the guidance system by a series of relay wires, also entered into the missile body via access panels. The photo detecting sensor and its housing, however, are added at this point only for beam riding missiles, in which case the housing is carefully bolted to the exterior diameter of the missile near its rear, facing backward to interpret the laser signals from the parent aircraft

Final assembly Insertion of the warhead constitutes the final assembly

phase of guided missile construction. Great care must be exercised during this process, as mistakes can lead to catastrophic accidents. Simple fastening techniques such as bolting or riveting serve to attach the warhead without risking safety hazards. For guidance systems that home-in on reflected laser light, the photo detecting sensor (in its housing) is bolted into place at the tip of the warhead. On completion of this final phase of assembly, the manufacturer has successfully constructed on of the most complicated, sophisticated, and potentially dangerous pieces of hardware in use today.

VARIOUS TYPES OF LGB The LGB flight path is divided into three

phases: ballistic, transition, and terminal guidance. During the ballistic phase, the weapon continues on the unguided trajectory established by the flight path of the delivery aircraft at the moment of release. In the ballistic phase, the delivery attitude takes on additional importance, since maneuverability of the UGB is related to the weapon velocity during terminal guidance. Therefore, airspeed lost during the ballistic phase equates to a proportional loss of maneuverability. The transition phase begins at acquisition. During the transition phase, the weapon attempts to align its velocity vector with the line-of-sight vector to the target. During terminal guidance, the UGB attempts to keep its velocity vector aligned with the instantaneous line-of- sight. At the instant alignment occurs, the reflected laser energy centers on the detector and commands the canards to a trail position, which causes the weapon to fly ballistically with gravity biasing towards the target.

VARIOUS TYPES OF LGB

Designation Guidance System Munition

GBU-2 KMU-421/B SUU-54/b 2000-lb cluster bomb

PAVEWAY I

GBU-10 A/B KMU-351 A/B Mk 84 2000-lb bomb

GBU-12 A/B KMU-388 A/B Mk 82 500-lb SNAKEYE

GBU-12 A/B KMU-420 /B Mk 20 Mod 2 ROCKEYE 500-lb bomb

GBU-12 A/B KMU-342 /B M117 750-lb bomb

PAVEWAY II

GBU-10 D/B KMU-351 E/B Mk 84 2000-lb bomb

GBU-12 C/B KMU-388 C/B Mk 82 SNAKEYE 500-lb bomb

GBU-16 C/B KMU-455 /B Mk 83 1000-lb bomb

QUALITY CONTROL Each important component is subjected to rigorous quality

control tests prior to assembly. First, the propellant must pass a test in which examiners ignite a sample of the propellant under conditions simulating the flight of a missile. The next test is a wind tunnel exercise involving a model of the missile body. This test evaluates the air flow around the missile during its flight. Additionally, a few missiles set aside for test purposes are fired to test flight characteristics. Further work involves putting the electronics suite through a series of tests to determine the speed and accuracy with which commands get passed along to the missile's control surfaces. Then the laser components are tested for reliability, and a test beam is fired to allow examiners to record the photo detecting sensor's ability to "read" the proper wavelength. Finally, a set number of completed guided missiles are test fired from aircraft or helicopters on ranges studded with practice targets.

USAGES

THE PROCESS OF USE THIS MISSILE IS DIFFERENT FOR AIR BASE AND LAND BASE MISSILE.

LAND BASE MISSILE

AIR BASE MISSILE

USAGES(LAND BASE MISSILE)

Spawn the base object. I used a barrel, but anything can do. Be sure to freeze it, as the rocket tends to take off if you wire things up in the wrong order. Nothing worse than a Wile E. Coyote impression.

Attach a GPS and a laser receiver. attach a Wired Numpad, we will use 1 to turn the thrusters on and off. (you really can use any

number but zero, because the vector thrusters multiplies the input number by what you set as the force multiplier)

attach three arithmetic chips set to 'subtract'. try to place them in such a way so as to make it easy to keep track of which chip is the x variable, which is the y, and which is the z. This can get confusing, and can go very wrong very fast, such as sending the missile flying into the ground, or you.

Set each arithmetic chip with B to the respective laser reciever coord (x,y,orz) and A to the respective GPS coord. Be sure that you have the B to the reciever and the A to the GPS and not vice-versa or you will have a laser repelled missile Another useful tip is to go from the chip to the module, or you will not be able to attach to the coord variables. This frustrated the author until he figured this out.

Set the numpad to be off. It will display a number on its popup if it is on. You want it off for now. Attach a vector thrusters with the coordiate system set to xyz world. Setting the system to local

will result in a rocket worthy of Wile E. Coyote himself. Also set the Force multiplier to your desired thrust, which is what it will be if you use "1" for the numpad. Check "toggle"

Wire the thrusters in this order: › Mul wired to the numpad output "1" › X to the arithmetic chip for x-coords › Y to the chip for y › Z to the chip for z

Using the laser pointer from the scripted weapons, register it to the laser pointer reciever using the secondary fire mode.

unfreeze the base object and flip on the numpad toggle (1 if you followed my plans). If you wired everything right the missile should follow wherever you point the laser pointer.

AIR BASE MISSILE The basic operational concept for laser guidance and targeting from

a combat aircraft was simple.   The Weapons System Operator would use a laser marking device mounted on the back-seat canopy of one F-4 to illuminate that target.  Another F-4 loaded with the laser guided bombs would make the attack dive bomb run.  Depending on fuel loads, the Phantom could carry two 2,000 pound guided bombs.   The number was fewer because the fixed guidance fins on the bomb only allowed one bomb per station on the fighter.  In later versions of the Paveway bomb, folding rear fins allowed for two bombs to be loaded on aircraft bomb station hardpoints

Diagram of an aircraft approaching a target to be destroyed by a laser-guided missile

BYPRODUCTS/WASTE Propellants and explosives used in warheads are toxic if

introduced into water supplies. Residual amounts of these materials must be collected and taken to a designated disposal site for burning. Each state maintains its own policy pertaining to the disposal of explosives, and Federal regulations require that disposal sites be inspected periodically. Effluents (liquid byproducts) from the chromium coating process can also be hazardous. This problem is best dealt with by storing the effluents in leak-proof containers. As an additional safety precaution, all personnel involved in handling any hazardous wastes should be given protective clothing that includes breathing devices, gloves, boots and overalls.

MODERN LASER GUIDED MISSILE

Modern laser-guided missiles can be self-detonated, thus requiring only a single aircraft, and their range has increased significantly. The laser-guided missiles use a laser of a specific frequency bandwidth to locate the target. The pilot must line up the crosshairs and lock successfully onto target. This laser creates a heat signature on the target. The weapon must be released during a certain window of opportunity. After it is launched, the missile uses its onboard instrumentation to find the heat signature. The target is acquired when the missile locates the heat signature. The missile is able to secure the target even if the target is moving.

THE FUTURE Future laser guided missile systems will carry their own

miniaturized laser on board, doing away with the need for target designator lasers on aircraft. These missiles, currently under development in several countries, are called "fire-and-forget" because a pilot can fire one of these missiles and forget about it, relying on the missile's internal laser and detecting sensor to guide it towards its target. A further development of this trend will result in missiles that can select and attack targets on their own. Once their potential has been realized, the battlefields of the world will feel the deadly venom of these "brilliant missiles" for years to come. An even more advanced concept envisions a battle rifle for infantry that also fires small, laser guided missiles. Operation Desert Storm clearly showed the need for laser guided accuracy, and, as a result, military establishments dedicated to their missions will undoubtedly invent and deploy ever more lethal versions of laser guided missiles.

REFERENCESWebsite www.sgspires.com www.wiki.garrysmod.com www.en.wikipedia.org www.nd.edu

Books JP 3-09.1, Joint Laser Designation Procedures, 1 June 1991, [PDF Size = 835K but

well worth the wait] Joint Laser Designation Procedures Training and Doctrine Command Procedures

Pamphlet 34-3 Safety information Laser Fire Control Systems Mil-Handbook-828, 1993 Fundamentals of Lasers LASER RANGE SAFETY Range Commanders Council, White Sands Missile Range,

OCTOBER 1998   Laser Guided Munitions CHAPTER 7 TACTICS, TECHNIQUES, AND PROCEDURES FOR

THE STRIKE / RECON PLATOON (STRIKER) Techno-Tips on Laser Guided Bombs