30-11-2012, 01:43 PM
ADAPTIVE MISSILE GUIDANCE USING GPS SEMINAR REPORT-2012
[attachment=41847]
INTRODUCTION
WHAT IS MISSILE?
The word missile comes from the Latin verb mittere, literally meaning "to send". They are basically rockets which are meant for destructive purposes only. Rocket-powered missiles are known as rockets if they lack post-launch guidance or missiles or guided missiles if they are able to continue tracking a target after launch. Cruise missiles typically use some form of jet engine for propulsion.
Missiles are often used in warfare as a means of delivering destructive force (usually in the form of an explosive warhead) upon a target. Aside from explosives, other possible types of destructive missile payloads are various forms of chemical or biological agents, nuclear warheads, or simple kinetic energy (where the missile destroys the target by the force of striking it at high speed). Sometimes missiles are used to deliver payloads designed to break infrastructure without harming people. For example, in the Persian Gulf War cruise missiles were used to deliver reels of carbon filament to electricity stations and switches, effectively disabling them by forming short circuits. Missiles which spend most of their trajectory in un-powered flight, and which don't use aerodynamics to alter their course, are known as ballistic missiles (because their motion is largely governed by the laws of ballistics). These are in contrast to cruise missiles, which spend most of their trajectory in powered flight.
. MISSILE COMPONENTS:
Guided missiles are made up of a series of subassemblies. The major sections are carefully joined and connected to each other. They form the complete missile assembly.The major components of a missile are:
• The guidance and control section
• The target detector section
• The rocket motor section.
• Armament Section
• Propulsion Section
Target detection: The target detector (TD) is a narrow-beam, active-optical, proximity fuse system. The purpose of the TD is to detect the presence of an air target within the burst range of the missile warhead and generate an electrical firing signal to the S&A device. They detect the presence of a target and determine the moment of firing. When subjected to the proper target influence, both as to magnitude and change rate, the device sends an electrical impulse to trigger the firing systems.
Rocket motoring section: The rocket motor consists of components that propel and stabilize the rocket in flight. Not all rocket motors are identical, but they do have certain common components. These components are the motor tube, propellant, inhibitors, stabilizing rod, igniter, and nozzle and fin assembly. The motor tube supports the other components of the rocket. Presently, all motor tubes are aluminum. The forward end contains the head closure and threaded portion for attachment of the warhead. The center portion of the motor tube contains the propellant. The section is the combustion chamber and contains the igniter, propellant grain, stabilizing rod, and associated hardware. The nozzle and fin assembly attaches to the aft end by a lock wire in a grove inside the tube. The aft end of the motor tube is threaded internally to accept the nozzle and fin assembly.
CONCEPT OF MISSILE GUIDANCE
Missile guidance concerns the method by which the missile receives its commands to move along a certain path to reach a target. On some missiles, these commands are generated internally by the missile computer autopilot.On others, the commands are transmitted to the missile by some external source.
TYPES OF MISSILE GUIDANCE
Many of the early guidance systems used in missiles where based on gyroscope models. Many of these models used magnets in their gyroscope to increase the sensitivity of the navigational array. In modern day warfare, the inertial measurements of the missile are still controlled by a gyroscope in one form or another, but the method by which the missile approaches the target bears a technological edge. On the battlefield of today, guided missiles are guided to or acquire their targets by using:
• Radar signal
• Wires
• Lasers (or)
• Most recentlyGPS
MISSILE GUIDANCE USING RADAR SIGNAL
Many machines used in battle, such as tanks, planes, etc. and targets, such as buildings, hangers, launch pads, etc. have a specific signature when a radar wave is reflected off of it. Guided missiles that use radar signatures to acquire their targets are programmed with the specific signature to home in on. Once the missile is launched, it then uses its onboard navigational array to home in on the preprogrammed radar signature. Most radar guided missiles are very successful in acquiring their targets; however, these missiles need a source to pump out radar signals so that they can acquire their target. Themajor problem with these missiles in today’sbattlefield is that the countermeasures used against these missiles work on the same principles that these missiles operate under. The countermeasures home in on the radar signal source and destroy the antenna array, which essential shuts down the radar source, and hence the radar guided missiles cannot acquire their targets.
MISSILE GUIDANCE USING WIRES
Wire guided missiles do not see the target. Once the missile is launched, the missile proceeds in a linear direction from the launch vehicle. Miles of small, fine wire are wound in the tail section of the missile and unwind as the missile travels to the target. Along this wire, the gunner sends navigational signals directing the missile to the target. If for some reason the wire breaks, the missile will never acquire the target. Wire guided missiles carry no instrument array that would allow them to acquire a target. One strong downside to wire guided missiles is the fact that the vehicle from which the missile is fired must stay out in the open to guide the missile to its target. This leaves the launch vehicle vulnerable to attack, which on the battlefield one wants to avoid at all costs.
MISSILE GUIDANCE USING LASERS
In modern day weaponry the buzzwords are fire and forget. Under this principle many modern day laser weapons were designed. Laser guided missiles use a laser of a certain frequency bandwidth to acquire their target. The gunner sights the target using a laser; this is called painting the target. When the missile is launched it uses its onboard instrumentation to look for the heat signature created by the laser on the target. Once the missile locates the heat signature, the target is acquired, and the missile will home in on the target even if the target is moving. Despite the much publicized success of laser guided missiles, laser guided weapons are no good in the rain or in weather conditions where there is sufficient cloud cover. To overcome the shortcomings of laser guided missiles presented in unsuitable atmospheric conditions and radar guided missiles entered GPS as a method of navigating the missile to the target. So, before going to GPS guided missile we will have an introduction to GPS.
[attachment=41847]
INTRODUCTION
WHAT IS MISSILE?
The word missile comes from the Latin verb mittere, literally meaning "to send". They are basically rockets which are meant for destructive purposes only. Rocket-powered missiles are known as rockets if they lack post-launch guidance or missiles or guided missiles if they are able to continue tracking a target after launch. Cruise missiles typically use some form of jet engine for propulsion.
Missiles are often used in warfare as a means of delivering destructive force (usually in the form of an explosive warhead) upon a target. Aside from explosives, other possible types of destructive missile payloads are various forms of chemical or biological agents, nuclear warheads, or simple kinetic energy (where the missile destroys the target by the force of striking it at high speed). Sometimes missiles are used to deliver payloads designed to break infrastructure without harming people. For example, in the Persian Gulf War cruise missiles were used to deliver reels of carbon filament to electricity stations and switches, effectively disabling them by forming short circuits. Missiles which spend most of their trajectory in un-powered flight, and which don't use aerodynamics to alter their course, are known as ballistic missiles (because their motion is largely governed by the laws of ballistics). These are in contrast to cruise missiles, which spend most of their trajectory in powered flight.
. MISSILE COMPONENTS:
Guided missiles are made up of a series of subassemblies. The major sections are carefully joined and connected to each other. They form the complete missile assembly.The major components of a missile are:
• The guidance and control section
• The target detector section
• The rocket motor section.
• Armament Section
• Propulsion Section
Target detection: The target detector (TD) is a narrow-beam, active-optical, proximity fuse system. The purpose of the TD is to detect the presence of an air target within the burst range of the missile warhead and generate an electrical firing signal to the S&A device. They detect the presence of a target and determine the moment of firing. When subjected to the proper target influence, both as to magnitude and change rate, the device sends an electrical impulse to trigger the firing systems.
Rocket motoring section: The rocket motor consists of components that propel and stabilize the rocket in flight. Not all rocket motors are identical, but they do have certain common components. These components are the motor tube, propellant, inhibitors, stabilizing rod, igniter, and nozzle and fin assembly. The motor tube supports the other components of the rocket. Presently, all motor tubes are aluminum. The forward end contains the head closure and threaded portion for attachment of the warhead. The center portion of the motor tube contains the propellant. The section is the combustion chamber and contains the igniter, propellant grain, stabilizing rod, and associated hardware. The nozzle and fin assembly attaches to the aft end by a lock wire in a grove inside the tube. The aft end of the motor tube is threaded internally to accept the nozzle and fin assembly.
CONCEPT OF MISSILE GUIDANCE
Missile guidance concerns the method by which the missile receives its commands to move along a certain path to reach a target. On some missiles, these commands are generated internally by the missile computer autopilot.On others, the commands are transmitted to the missile by some external source.
TYPES OF MISSILE GUIDANCE
Many of the early guidance systems used in missiles where based on gyroscope models. Many of these models used magnets in their gyroscope to increase the sensitivity of the navigational array. In modern day warfare, the inertial measurements of the missile are still controlled by a gyroscope in one form or another, but the method by which the missile approaches the target bears a technological edge. On the battlefield of today, guided missiles are guided to or acquire their targets by using:
• Radar signal
• Wires
• Lasers (or)
• Most recentlyGPS
MISSILE GUIDANCE USING RADAR SIGNAL
Many machines used in battle, such as tanks, planes, etc. and targets, such as buildings, hangers, launch pads, etc. have a specific signature when a radar wave is reflected off of it. Guided missiles that use radar signatures to acquire their targets are programmed with the specific signature to home in on. Once the missile is launched, it then uses its onboard navigational array to home in on the preprogrammed radar signature. Most radar guided missiles are very successful in acquiring their targets; however, these missiles need a source to pump out radar signals so that they can acquire their target. Themajor problem with these missiles in today’sbattlefield is that the countermeasures used against these missiles work on the same principles that these missiles operate under. The countermeasures home in on the radar signal source and destroy the antenna array, which essential shuts down the radar source, and hence the radar guided missiles cannot acquire their targets.
MISSILE GUIDANCE USING WIRES
Wire guided missiles do not see the target. Once the missile is launched, the missile proceeds in a linear direction from the launch vehicle. Miles of small, fine wire are wound in the tail section of the missile and unwind as the missile travels to the target. Along this wire, the gunner sends navigational signals directing the missile to the target. If for some reason the wire breaks, the missile will never acquire the target. Wire guided missiles carry no instrument array that would allow them to acquire a target. One strong downside to wire guided missiles is the fact that the vehicle from which the missile is fired must stay out in the open to guide the missile to its target. This leaves the launch vehicle vulnerable to attack, which on the battlefield one wants to avoid at all costs.
MISSILE GUIDANCE USING LASERS
In modern day weaponry the buzzwords are fire and forget. Under this principle many modern day laser weapons were designed. Laser guided missiles use a laser of a certain frequency bandwidth to acquire their target. The gunner sights the target using a laser; this is called painting the target. When the missile is launched it uses its onboard instrumentation to look for the heat signature created by the laser on the target. Once the missile locates the heat signature, the target is acquired, and the missile will home in on the target even if the target is moving. Despite the much publicized success of laser guided missiles, laser guided weapons are no good in the rain or in weather conditions where there is sufficient cloud cover. To overcome the shortcomings of laser guided missiles presented in unsuitable atmospheric conditions and radar guided missiles entered GPS as a method of navigating the missile to the target. So, before going to GPS guided missile we will have an introduction to GPS.