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amr mohamed
 
 


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PostSubject: Radar   Wed 16 Mar 2011, 7:44 am


Radar




Radar word shortcut for any Ring Radio waves radio ring

Definition Radar

Radar and scalability of the implementation of several functions to make it useful
For different purposes and wide; it depends on the radar for pilots landing their planes
Safely in crowded airports, as used by mariners in bad weather
To lead their ships near the boats and dangerous goals. And uses a lot of countries
Radar guard of sudden attacks from enemy aircraft and missiles, as
Can be employed on weather radar to track storms, air
Approaching. Scientists use radar to investigate the Earth's atmosphere above, as
Also used to study other planets and moons.
Radar electronic system is used to detect
Fixed or moving targets and determine their locations. The radar can determine the direction of
Targets far from the vision of the human eye, as well as determine its distance and height, as
It can find the goals of small insects or the enormity of the mountains. The radar works
Efficiently at night, even in dense fog, rain or snow.


The device works almost every radar waves is mediated by
Towards the target radio, the reception of waves reflected from it. Indicates time
It takes to waves reflected back over the target and how far?, This
In addition to the direction in which waves reflected back from the position of the target.


Different radars in size and shape, but
They are all essential parts of one; sender and per device for the production of signals
Radar, and an antenna for broadcast abroad, and brings the antenna itself in the most
Types of radar waves, the feedback from the target. And strengthens the future waves
Reflected by the so called resonances can be seen on the screen. Similar to the screen
Radar picture tube in your TV, but they are often circular
Instead of being rectangular. The show echoes points of light, or fiction
For the target viewer.


Date radar

In 1904 invented the German Christian
Holsmier a simple device that uses radio beams to prevent the ship from collision
Each other in the sea, and in 1922 appeared the first system for long-term effects on radio
Hands of the Italian scientist Guglielmo Marconi




Christian Hulsmeyer



Uses radar

It is known that air traffic near big airports
Be quite dense, so traffic controllers used radar trainers
All major airports in the world to guide the continuous flow of aircraft coming
And departure; The radar shows the position of the observers of each aircraft in the air at the end
Minimum of 80 km from the airport. And enable this information to prevent collisions
Choose the most appropriate paths to be followed by the pilots. Observers also depends on the
Radar to guide them to the ground when landing bad weather, and when the
Become pilots to see the lights and stands hard as they approached.


And defines a system called secondary radar, the aircraft
Observers screens in air traffic. Emit a radio signal transmitter on
The plane, sends signal cryptographic due, the plane containing the call sign. And this reference
Draw on the screen beside the point, which represents the plane.

And most modern aircraft of different types of radars
To help the pilot. For example, shows the amount of radar altimeter
Altitude aircraft in flight, pilots, and so help to maintain the high
Appropriately. There is another way, is the weather radar that detects storms nearby, and so
Pilots can change the paths to avoid bad weather as they can
Based air traffic control centers on the radar
To track and guide aircraft in flight between airports. And appears waves
Reflected from the aircraft radar illuminated points on the circular screen. Can
Determine the flight path for each aircraft movements follow-up points. In navigation
Air. Radar is an important tool in navigation. The shares used in each
Airports and aircraft to a large extent in the safety of navigation


.



In maritime navigation. The use of radar
Widely as a catalyst for the navigation in many types of boats and ships,
From a vehicle cruise small to large oil tankers. A ship radar
In bad weather conditions to locate other ships and rocks
And snowy mountains at the appropriate times to avoid accidents. Can Navigator,
When the ship is near the beach, to locate the ship-mediated Echoes
Radar reflectors private floating, or islands, or other land marks.


Officials use the port radar to control the
Ships in the busy ports. They follow the tracks of movement of all ships in the port
On the radar screen, which gives what looks like a map of the port. And mediated
Radiocommunication these officials can guide vessels entering
And out of the harbor safely in any weather conditions.

Stations can also track the effects of Coast Guard ships
During the radar observations, and the Coast Guard uses radar to search for
Ships of the Code and reported as unaccounted for.

In the armed forces. Radar uses a wide variety of
In the armed forces, including the following main applications:

1 - Air Defense
2 - Missile Defense
3 - Space Surveillance
4 - poll
5 - Measuring range
6 - Control of fire arms

Space surveillance radars include the use of high-capacity
To detect and track satellites, as well as any other targets placed in orbit
Around the Earth. For this purpose, to invest the United States and Canada called the network system
Detection and prosecution of space. The system includes three facilities of the defense system
Missile, and eight other facilities in different locations of the world. He believes this
System of approximately 20,000 daily monitoring of hundreds of tropical goals (which revolves
Around the Earth). And help data from those observations in the identification of
Reconnaissance satellites used for spying.


Radar mapping can be done from an airplane, and this
Radar map of the city of Flagstaff, Arizona, United States
America, (right), taken from 12 000 m high and the city show a cluster
Of yellow photographs. The shape of the land mass to the left of the city is Mount
Elden.


Survey - data collection.
Uses radar to gather information on the preparations
Taken by other States for the war. Can radar mapping mobile
Plane to produce detailed maps of the Earth, shows the military installations
And equipment. Can other types of radars to obtain important information on
Rocket systems for the control of another State during the missile test launch.


Measurement range. Uses
Radar is often used to examine the long view to ensuring the performance of military equipment.
For example, radars can measure the extent to accurately track the missile flight
Again. If it is not the performance of the rocket as expected, it can be to trace data that
Help the designer to identify the error.


To control traffic speed and flow.
The police use radar in some countries to apply
The laws of speed and make sure the speed of vehicles on streets and highways.
The radar can detect moving police vehicle accelerated from
After about 370 meters. And radar signals transmitted from the antenna outside the compound
Police vehicle
.


How Radar Works

How does the radar pulse

Radar sets differ in design and purpose,
But all work on the same general principles. Produces all
Radars and broadcast signals in the form of electromagnetic waves. Can
Of radar waves to be radio waves or light waves.
Most of the radar sets transmitted radio waves, but few of them called
Optical radar or laser radar transmitted wavelengths of light.


When you set the radar waves
These radio waves hit the target and reflected, and back section of the waves
Reflected to a radar on the same path, who sent it.
This is similar to reflection, to a large degree, what happens when people screaming in the valley
Mountain, heard his cry echoed from the rocks nearby. In this case reflected
Sound waves instead of radio waves or light.


The waves sent by the radar frequency
Specific. And measured the frequency of such wave unit called MHz. Equal to unity
Almijahrtz megahertz (rpm). For the waves of radio frequencies
For low frequencies of light waves, and most of the radars that airs on
Radio waves operating at frequencies between 1,000 MHz and 50,000
MHz. Optical and radar operating at frequencies much higher, and some
Generates light waves with frequencies up to one billion MHz.


And designed sets radars, in the conditions of
Several, for different purposes and operate at different frequencies. And the radar
Operating at low frequencies is more effective than those operating at frequencies
High to penetrate clouds, fog and rain, so widely used in
Aircraft and ships. On the other hand gives the radar of
High frequencies, accurate measurements and antennas smaller than those used
In the low-frequency radars. Radar can photosynthesis, the
For example, the production of a signal with very narrow beam from a laser with a diameter of
Only 1.3 cm. Optical radars and are particularly useful in survey
Harsh terrain, must be measured in terms of points away from the gaps between
Things Kackor large trees.


The groups differ also in the radar
How to send signals, and are classified on this basis the two general types are
:


A radar pulse is
The most common

Broadcast signals in the form of bursts of strong
Intermittent, or pulse, and continue to pulse radar waves, a few
Parts per million of a second. And for a pulse radar antenna and one
Alternately used to send and receive pulses repercussions.

Can find the distance to one of the goals
Measuring the time it takes for the radar wave to reach this goal
And return. The rest of radar waves travel at speeds of electromagnetic waves
Light 299.792 km / s. So Valmujp radar return after two seconds
Have made 599 584 km, ie 299 792 km to go to the target and the distance
The same in return, the transformation of the radar pulse automatically set the time required
A return trip to the space (yet) towards the target.


The broadcast antenna pulses
Wave in a narrow beam enables a highly directional radar
Determine the direction of the target. Can not reverse waves only goal, which is located in
The size of the package only. And determines the direction of the reflected waves into the goal.
Radar can pulse chase (follow) the goal, sending continuous signals
Pulse, and measure the distance and direction of the target at regular intervals. It uses this type
Of the radar also for mapping radar from an airplane. The map can be produced
Radar scans the beam over a selected area, and mapping the intensity of echoes from all
Direction. Show resonances in the form of an image on the radar screen, and recorded on film
Projector. And produce goals, such as buildings, bridges, mountains, pictures of shiny,
Because it reflects the strong echoes.



2
Continuous wave radar

Broadcasts a continuous signal
Instead of short bursts, and there are two types of continuous-wave radar,
Are:
Doppler radar is mainly used
Accurate measurements of speed, and it works on the principle of the Doppler effect, a change to the
Frequency caused by movement. Doppler radar sends a continuous wave frequency fixed,
It uses the same antenna in both transmission and reception. When the wave hits
Sent a view of approaching the radar, reflected waves at a higher frequency of
Frequency sender. And when the target away from the radar set, the wave
Feedback becomes less frequency and, as the fastest goal in any of the
Directions difference was even greater between the frequency of sending and frequency
Reflected. By measuring the difference in the frequency determines the speed of the target Doppler Radar
Observer.

And the police use Doppler radar to detect drivers
Those who speed. The soldiers used to measure the speed of targets to guide fire arms.


Radar frequency modulation broadcasts also a sign of continuing, but
That increase or decrease the frequency signal at regular intervals. As a result, the radar
Frequency modulation, in contrast to Doppler radar, can determine the distance to the goal of constant
Or mobile. At the time, which has a radar signal to the target and return, be
Frequency target the sender has changed. Measured by the difference between the echo and reverb
The sender, and converted to a distance of the target, which produces the echo. As the goal was far
Increased the difference between the frequencies.
Can be used include radar frequency, such as
Pulse radar, mapping, and in the prosecution. It can be used to
Aircraft, a measure of height.


A Doppler radar
2 radar frequency modulation
.


Group sections
Radar

Varies depending on the size of the radar
Use; The group of radar used by police to detect vehicles
Nearby accelerated, can be carried by hand, and weighs about 18 kilograms. The units
Huge radar used for the study of the planets and other targets remote,
Include large buildings. Some of these units antennas up to 300 m in diameter.

In spite of the different groups
Radar are similar in size in the subdivision, and these sections are:


1 -
Oscillator:
Device which produces an electrical signal with low power frequency
Fixed.
Set the frequency oscillator frequency radar work of a group.


2 -
Included:
In the pulse radar, electronic key, it connects the
The sender and separated quickly. Thus, the sender produces bursts of short wavelengths. In
Radar frequency modulation changes the embedded wave sent down. And not
Doppler radar is embedded.


3 -
Sender:
Serve as speakers, as it takes the signal
Electrical low capacity, and produces high-power signal. For
Example, produces pulse radar transmitter, the user in control
Air navigation, a reference to a maximum capacity of several million watts.


4 -
Key transmitters and receivers:
You can use a single antenna for both transmission
And reception. The key to driving the transmission and reception signals the sender to
Antenna, and prevents these signals from the flow into the future. References
Strong from the sender that may damage the future if it involves sensitive. After
Send to a wave antenna conducts key transmitters and receivers, to the future
Antenna.
This enables the future delivery of the next pick up echoes.


5 -
Antenna:
Large dish antenna rotor is used in the radar stations on the
Distant Early Warning Line, and wipe these reflectors that are automatically
The sky, for the detection of enemy aircraft. Antenna. Sends signals
Radar in the form of a narrow beam of electromagnetic waves, and combines
Reflected echoes. Since most radar units have a modern key
Transmitter and receiver, it uses the same antenna for transmission and reception.

It consists of the common type of horn antennas attached to the
Introduction to large reflector dish called reflecting. Called trumpet band radar,
Verzha reflector in a narrow beam. The radar antenna is going, so spread
This package on the radar scanner targets in all directions.

Used in radar sets of other types of
Antennas operating at lower frequencies or at high frequencies
Too. It uses radar, which broadcasts low frequency radio waves
Antennas are made of metal tubes, rods or similar external antennas
Of the TV. Used in optical radar, a device different
Pena sends high-frequency waves like light or ultraviolet light
The visible or infrared. This is similar to the means and the telescope (the telescope)
And has a glass lens focuses waves emerging in the package.


6 -
Future:
Takes weak resonances accrued mediated antenna
And magnified a lot. And the future is so sensitive that it can easily detect
Resonances with a capacity of less than one millionth of a watt. And nominate
The future noise and other interference originating from the antenna.


7 -
Signal processor:
With the reference of the future, in most
Radar units, through a handler for the signal before she went to the screen. And lead
Signal processor and different functions in the radar used for different purposes,
It is obscure in some types of radar echoes of the objectives of sustained and substantial,
And allows only for the echoes from small targets moving up to the screen.
So they can factor the radar signal processor, see the aircraft on the
For example, although the echoes of the plane up at one time with
Is much stronger echoes coming from Mt. The computer in many organs
Place of modern radar signal processor
.



8 -
The viewer (the screen):
Provides for workers in the radar information
Received for the goal. Some radar sets a simple viewer. Fradarat
Doppler phones used by the police, for example, a scale indicates
To the speed of a vehicle or truck, but most of the groups opposed the radar
Complex, composed of the cathode ray tube, a magnetron provider
Viewer TV-like fluorescent. See: vacuum tube. The viewer can
Cathode ray tube display radar data in many forms.

The most common viewer is a viewer position indicator
Surface, and give us more similar to a map of the area scanned Pack
Radar. And agrees center of the image into radar range. And the area around the viewer
Included such as the compass and to read the direction. It can be opposed to services
Spread from the center of the image to its surroundings to show the distance in miles or
Kilometer. The radar echoes appear in the form of bright spots. Gives
Point position for scaling the compass direction of the target. And found a space point
The amount of the center of the screen after the goal. And can determine the speed of the target observation
The time it takes the point to cut a certain distance Viewer radar.

Show symptoms of other forms of high end,
And uses this type of symptoms in radar sets designed
To help steer the plane during landing.


9 -
Timer:
Radar Group believes running efficiently and easily.
And reached this Alnbitp main parts of the Group of radar accurately and separated in
Time automatically, and the timer is doing this by sending signals
Control to various sections of the appropriate sequence


.

cherry

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