amr mohamed
Occupation: : 369 Date of Birth : 1994-09-29 Join Date : 2010-11-12 Age : 29
| Subject: 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
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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
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