Guided Missile Final.ppt 6m1c5x

MISSILE GUIDANCE SYSTEMS BY

KRUNAL SATHAVARA DEPT: ELECT & COMM YIT-JAIPUR •1

AIM To discuss about different types of missile guidance system

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SEQUENCE • Missile • Guided Missile • Missile components • Working of guidance system • Types of guidance system • Q &A

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MISSILE • Latin word „Mittere‟ means “To send” • A self propelled projectile used as a weapon • Typically propelled by rocket or jet engines

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GUIDED MISSILES  Self-propelled aerial projectiles containing explosives  Guided either by remote control or internal mechanisms  5 categories – surface to surface, surface to air, air to surface, air to ground & air to air  Based on area of operation – tactical, & strategic  Based on flight characteristics – aerodynamic & ballistic •5

MISSILE COMPONENTS  Guidance, control, armament & propulsion sections  Guidance – brain of the missile, directs its maneuvers  Control – executes the maneuvers  Armament – carries the explosive charge and the fusing & firing sections  Propulsion – propels the missile  Guidance orders are initiated by electronic sensing

systems

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WORKING OF A GUIDANCE SYSTEM  Consists of 2 separate systems – altitude control & flight path control  Altitude control – maintains the missile in the desired altitude by controlling it in pitch, roll & yaw  Flight path control – guides the missile to its

designated target; done by determining flight path errors & generating orders for error correction  Orders then sent to missile control sub-system which exercises control to maintain flight path

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Categories of guidance systems  Guidance systems are divided into different categories according to what type of target they are designed for - either fixed targets or moving targets.  The weapons can be divided into two broad categories,

1.Go-Onto-Target(GOT) 2. Go-Onto-Location-in-Space (GOLIS)

GOT/GOLIS • A GOT missile can target either a moving or fixed target. • A GOLIS weapon is limited to a stationary or near-

stationary target. • The trajectory that a missile takes while attacking a moving target is dependent upon the movement of the target. Also, a moving target can be an immediate threat to the sender of the missile. • The target needs to be eliminated in a timely fashion in order to preserve the integrity of the sender. In GOLIS systems the problem is simpler because the target is not moving.

GOT systems  In every GOT system there are three subsystems:

•Target tracker • Missile tracker • Guidance computer  The way these three subsystems are distributed between

the missile and the launcher result in two different categories: • Remote Control Guidance: The guidance computer is on the launcher. The target tracker is also placed on the launching platform. • Homing Guidance: The guidance computers are in the missile and in the target tracker.

TYPES OF GUIDANCE SYSTEMS       

Inertial guidance Command guidance Beam-rider guidance Homing guidance – active, semi-active, ive LASER GUIDANCE WIRE GUIDED MISSILE INFRARED GUIDED MISSILE

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INERTIAL GUIDANCE  Missiles controlled by self-contained accelerometers  Accelerometers measure vertical, lateral & longitudinal 

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accelerations During flight outside forces cause changes in speed commands which are transmitted to missile by-radio uplink transmitter or by varying characteristics of missile guidance beam This data is taken by onboard computers & converted to precise position of missile Lately inertial systems have been combined with GPS – used in ICBMs Suffer from drift – chances of missing target are higher •13

COMMAND GUIDANCE  Tracking and guidance are ground based  Uses two radars, one to track the target and the other to track

the missile  The bearing and elevation of the radar trackers is monitored by a computer which directs the control system to alter the missile trajectory until it reaches the target  This system uses a human operator to observe the trajectory of the missile, and direct its control system by remote control radio link  This system is broadly similar to radio command, but is less susceptible to electronic counter measures. The command signals are ed along a wire (or wires) dispensed from the missile after launch •14

COMMAND GUIDANCE  Three accelerometers, mounted on a platform space-

stabilized by gyros, measure accelerations along three mutually perpendicular axes; these accelerations are then integrated twice, the first integration giving velocity and the second giving position. The system then directs the control system to preserve the pre-programmed trajectory

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COMMAND GUIDANCE

Missile

Target Command Transmitter

Missile Tracker #2

Computer

Target Tracker #1

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BEAM-RIDER GUIDANCE  Missile seeks out centre of controlled directional energy      

beam – radar beam Beam provides information regarding position of missile to guidance system System interprets this information & generates its own correction signals to keep missile at centre of beam Fire control radar points beam at target and the missile "rides" the beam to the target As beam spreads out – more difficult for missile to remain at centre of beam As range increases, accuracy of beam-rider decreases Effective only against short & medium range targets

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Beam Rider Guidance

Narrow Guidance Beam

Tracking Beam

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HOMING GUIDANCE  Controls path of missile by means of a device in missile that detects and reacts to some signal from target  Signal may be light, radio, sound, heat waves or magnetic field  System tracks energy reflected off target  Missile derives guidance error signals based on its position relative to target  Most accurate type of guidance  3 types – active , semi-active & ive •19

ACTIVE HOMING  Target illuminated by component within

missile – radar transmitter  Radar signals transmitted by missile,

reflected off the target & received back by receiver  This gives information – target’s distance

& speed  Missile sends electronic commands to

control section  Control section Controls angle of attack •20

SEMI-ACTIVE HOMING  Target illuminated by external

source – transmitter carried in launching aircraft  Receiver in missile receives

reflected signals , computes information & sends electronic commands to control section  Hawk anti-aircraft systems

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IVE HOMING  Directing intelligence is

received from target itself

 This may be a source of

infrared rays (such as the hot exhaust of jet aircraft) or radar signals (such as those transmitted by ground radar installations)

 Missile receiver receives

signals generated by the target and then the missile control section functions in the same manner •22

LASER GUIDANCE Laser guidance is a technique of guiding a missile or other projectile or vehicle to a target by means of a laser beam.

WIRE-GUIDED MISSILE A wire-guided missile is a missile guided by signals sent to it via thin wires reeled out during flight.

INFRARED HOMING

Infra-red homing refers to a guidance system which uses the infra-red light emissions of a target to track it. Missiles which use infra-red seeking are often referred to as "heat-seekers". Infra-red is just below the visible spectrum of light and is radiated mostly by hot bodies.

MAJOR GUIDANCE TECHNIQUE  Long Range Navigation (LORAN)  Global Positioning System (GPS)  Laser designation  Optical guidance

Long Range Navigation (LORAN) This was the predecessor of GPS and was (and to an extent still is) used primarily in commercial sea transportation. The system works by triangulating the ship's position based on directional reference to known transmitters.

Global Positioning System (GPS) This system of satellites provides extremely accurate position information. The receiver's position is triangulated using satellites in known orbits. Commercial receivers are limited in how accurately they may provide position data, as well as the maximum velocity at which they may operate. This is to prevent their use in manufacturing weapons.

Optical guidance Guided missiles use stored images of the terrain they are to fly over and an external sensor to track their current position. This guidance system was extremely expensive and not suitable for use in small payload operations. These were used on cruise missiles before the advent of GPS, which is both cheaper and more accurate. Devices that implement optical guidance incur high costs because of the high on-board processing requirements needed to check the current location against the course data

FIRE & FORGET Fire and forget is the military term for a type of missile which does not require further guidance after launch such as illumination of the target, and can hit its target without the launcher being in line of sight of the target.

CONCLUSION  Guidance System is a complex system which involves

several systems working in tandem  Development of missile involve huge expenditures – essential that guidance system is properly designed for accurate interception of targets

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REFERENCES  1) GPS Theory and Practice. B. Hofmann - Wellenhof, H. Lichtenegger, and J. Collins. Springer-Verlag Wien. NewYork. 1997. Pg [1-17, 76].  2) ttp://www.navcen.uscg.gov/pubs/gps/Icd200/icd200cw1234.pdf  3) E.D. Kaplan, Understanding GPS:Principles and Applications.  4)http://www.aero.org/news/current/gpsorbit. html.

 5) http://www.trimble.com/gps/  6)http://wikipedia.com

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