A Report on Ballistic Missiles Deborah Joseph *1, Jayashree
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JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 A Report on Ballistic Missiles Deborah Joseph *1, Jayashree. S *2 #Department of Aeronautical Engineering, Anna University [email protected] [email protected] Abstract — This journal presents an analytical study on the various types of ballistic missiles and the basic missile systems. It compares the different characteristics of each type with numerous examples and some factors such as ballistic coefficient that aids in obtaining an accurate evaluation. It also includes a few basic MATLAB codes for simple mathematical computations which aid in evaluating the apt trajectories of the ballistic missiles. I. INTRODUCTION The word missile comes from the Latin verb mittere , meaning “to send”. Missiles are greatly used in the military both to defend and to attack. In the words of laymen, a missile is a body capable of being thrown or journaled to strike a distant object. In scientific terms though, a missile is a self-propelled precision-guided munition system, as opposed to an unguided self -propelled munition, referred to as a rocket. These are categorized as ballistic missiles and cruise missiles. A cruise missile is a guided missile used against terrestrial targets that remains in the atmosphere and flies the major portion of its flight path at approximately constant speed. Cruise missiles are designed to deliver a large warhead over long distances with high precision. Modern cruise missiles are capable of travelling at supersonic or high subsonic speeds, are self-navigating, and are able to fly on a non-ballistic, extremely low-altitude trajectory. In this journal, we are mainly concentrating on ballistic missiles. A ballistic is a missile that follows a ballistic trajectory with the objective of one or more warheads to a predetermined target. A ballistic missile is only guided during relatively brief periods of flight and most of its trajectory is unpowered and governed by gravity and air resistance if in the atmosphere. This contrasts to a cruise missile, which is aerodynamically guided in powered flight. Long range intercontinental ballistic missiles (ICBM) are launched on a sub-orbital flight trajectory and spend most of their flight out of the atmosphere. The shorter- range ballistic missiles stay within the earth’s atmosphere. MATLAB plays a major role in trajectory shaping for various ballistic missiles and provides a ballistic target flight trajectory simulation which aids in evaluating its precision and helps in making the required amendments in the missile systems. Numerous algorithms are used in MATLAB in order to compute various values and obtain the perfect trajectory for a ballistic missile, which is highly reliable. II. Chapter-1- MISSILE SYSTEMS A. Introduction The invention of missiles was inspired by rockets which were used since A.D 1232 by the Chinese. Rockets could be in other words called the “unguided missiles”. The early usage of rockets was as weapons in wars and later on was developed to be used for communication or signals. The idea of creating guided missiles was greatly influenced by aircrafts. The history of guided missiles dates back to the beginning of World War I when the idea was born and implemented in World War II by the Germans (V1 and V2 series of guided missiles). In the simplest of terms, Missile is an unmanned guided weapon. It is a precision-guided munition that hits the specified target precisely with no collateral damage and maximum destruction of the target (enemy’s assets). Basically missiles are categorized into Guided and Unguided missiles; but in this chapter we will be discussing only about the guided missiles, its classifications, systems and properties. Guided missiles are also known as homing missiles. Volume V, Issue XII, December/2018 Page No:2248 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 Homing guidance is generally of active, semi-active, or passive type. Once the active missiles are launched to the target they are capable of guiding themselves independently. These are also called launch- and-leave missiles and are heavier than semi-active and passive missiles. The active guided missile have a radiation source, this radiation from the interceptor missile radiates and strikes the target and is reflected back. The missile then guides itself on this reflected radiation. In case of passive missiles, the radiation originated by the target or some other source that is not a part of the overall weapon system is used. While a semi-active missile uses a combination of both active and passive missiles, the source of radiation in these types of missiles is at the launch point which radiates energy to the target. This energy is reflected back to the missile and sensing the reflected radiation the missile homes on it. B. Technology Missiles basically have five major system components; 1. Targeting system 2. Guidance system 3. Flight System 4. Propulsion System/Engine 5. Warhead Targeting systems One of the most essential parts of Missiles is its targeting system. There are numerous ways in which missiles can be targeted, the most common being the use of some type of radiation such as infrared, radio or lasers to guide the missile onto its target. If the location of the target is known, then guidance system such as Inertial Navigation System, Terrain Contour Matching or Satellite Guidance is used which calculates the course between the missile and target when the location of both these components is known . This work also can be done by a human operator who can visualize the target and the missile and guide it using either cable or radio-based remote control or by an automatic system that can simultaneously track the target and the missile. Volume V, Issue XII, December/2018 Page No:2249 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 Guidance Systems The three major parts of the guidance system of the missiles are navigation, guidance and control. Navigation tracks the existing location of the missile; guidance directs the missile in the accurate direction of the target by taking navigation data and the target information as input. On the grounds of the profile of the target, guidance system is classified into Go-onto-target (GOT) and Go- Onto- Location-in- space (GOLIS). GOT is highly efficient on both stationary and moving targets while GOLIS is mostly successful in cases with stationary or almost stationary targets. Line of sights system, pure pursuit and proportional navigation are the most used Guidance Systems. Flight Systems The Flight system uses the data from the targeting or guidance system to maneuver the missile in flight, allowing it to convert inaccuracies in the missile or to follow a moving target. There are two main systems: 1. Vectored thrust- enables the missile to manipulate the direction of thrust in order to gain control over the attitude or the angular velocity of the missile. 2. Aerodynamic maneuvering- since missiles do not posses conventional control surfaces, they employ aerodynamic control surfaces in order to maneuver the missile in the desired direction. Engine Missiles are obviously powered by rockets engines. Rockets are generally of the solid propellant type for ease of maintenance and fast deployment, although some larger ballistic missiles use liquid-propellant rockets. Long-range missile may have multiple engine stages, particularly in those launched from the surface. These stages may all be of similar types or may include a mix of engine types. For example, Surface- launched cruise missiles often have a rocket booster for launching and a jet engine for sustained flight. Some missiles may have additional propulsion from another source at launch; for example, the MGM-51 S Shillelagh was fired out of a tank gun. Warhead Missiles generally have one or more explosive warheads, which provide primary destructive power to the missile and also sometimes provide extensive secondary destructive power due to the high kinetic energy of the weapon and unburnt fuel that may be on board. Warheads are most commonly of the high explosive type, often employing shaped charges to exploit the accuracy of a guided weapon to destroy hardened targets. There are some types of warhead used in missiles are sub munitions, incendiaries, nuclear weapons, chemical, biological or radiological weapons or kinetic energy penetrators. Without warhead missile cannot be constructed, the warheadless missiles are often used for testing and training purposes. C. Types of Missiles Missiles are generally categorized by their launch platform and intended target. In broadest terms there will either be surface i.e ground or water, and then sub-categorized by range and the target type. Missiles require some modification in order to be launched from the air or surface, such as adding boosters to the surface-launched version. 1. Surface-to-surface missile 2. Air-to-surface missile 3. Surface –to-air missile Volume V, Issue XII, December/2018 Page No:2250 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 4. Air-to-air missile 5. Anti- satellite weapons Figure 2.1The various types of missiles Surface-to-surface missiles Figure 2.2 Surface-to-Surface Missile- Prithvi II-Range of 205- 350 km A surface -to-surface missile (SSM) or ground -to-ground missile (GGM) is a missile designed to be launched from the ground or the sea and strike targets on land or at sea. They may be fired from hand- held or vehicle mounted devices. They are often powered