Rada . Radio Detection And Ranging

Radar is an electromagnetic system that detects the location of an object. This system was invented in the Second World War, in which one can find objects located far away with the help of a special type of electromagnetic wave, the object of the enemy (especially the plane) or the object's address. It is applied in which radio waves are sent to the target and the echo reflected from it is analyzed ,

In radar systems, when radio waves are transmitted to a distant object. So sudden conductivity in the medium σ Volatile ∈ And magnetism μ Changes in the medium.

                                                            Long-range radar antenna

Due to this change in the medium, some part of the electromagnetic energy is absorbed through the medium and gets irradiated. Or the change itself helps the radio waves to hit the object and roll them back. Re-transmitted energy from the object is received by the receiver at the radar station. High power magnetron is used to find the correct location of the object.

There are mainly two types of radar systems.

Continuous wave radar-

CW radar- is a type of radar system where a known stable frequency continuous wave energy is transmitted and then received from any reflecting objects. Individual objects are detected using the Doppler effect, which causes the received signal to have a different frequency than the transmission, allowing it to be detected by filtering out the transmitted frequency.

Moment radar-

A Doppler radar is a special radar that uses the Doppler effect to produce velocity data of objects at certain distances. It does this by bouncing the microwave signal from a desired target and analyzing how the motion of the object has changed the frequency of the returned signal. This variation makes direct and highly accurate measurements of the radial component of a target's velocity relative to the radar. Doppler radars are used in aviation, sounding satellites, Major League Baseball's statecast system, meteorology, radar guns, radiology

Working principle-

The radar system consists of a modality transmitter receiver antenna and a duplexer that is transmitted through the transmitter Tx section into a low pulse powerful pulse space that is transmitted to space with the help of an antenna. Due to the various changes in the medium, these waves are reflected from distant objects and spread again in space.The receiving antenna Rx collects the received energy in the form of these reflected waves and then transmits it to the receiver.

                                                            Radar working diagram

In the radar system, the duplexer serves for both transmission and reception.

1. It isolates the transmitter and receiver
2. It protects the receiver in case of power transmission
3. This signal antenna is useful for transmitter and receiver

The antenna used in this system is a uni - directional. Often the same antenna is used for transmitting and receiving. Due to this, time division multiplexing management is used because radio energy is transmitted in the form of pulses.

With the response of an internally generated trigger, the transmitter generates a rectangular pulse. When a small portion of the pulse power is fed into the duplexer, the duplexer disconnects the receiver's connection to the antenna and connects it to the transmitter. As the antenna is a directional, it transmits the plus in the direction in which it points. When this pulse is terminated by the object, the duplexer breaks the connection with the transmitting antenna and becomes connected to the receiver. These pulsos are received and amplified and demodulated by the receiver, Terminating pulses such. Fed from the device which displays them appropriately

 The distance of the object can also be determined with the help of radar. In this method the distance unit of distance is nautical miles or nmi which is equal to 1852m

General Requirement -

1. Dulex should do automatic work
2. In the echo period the transmitter must be switched off
3. The transmitted pulse must be powerful
4. The receiver must be sensitive to the signal (pulse, echo)
5. Amplification of receiver signal is required
6. Antenna should be high directive and high gain receiver
7. Antenna must be a - directional.
8. The small portion of the pulse should feed into the dulexor
9. The medium needs to be changed so that the pulse can terminate from the object

 Uses-

• Moving targets are used to determine the speed of automobile, shell, guided missile
• It is used to determine the height of the plane from the ground
• Used in Satellite Services
• It easily detects and targets the anime target even in the dark of night
• Is used to search for submarine, land mass and voice.

Advantages-

• It measures the distance of the object
• It uses the same antenna for transmitter and receiver
• It shows the exact position even at a greater or lesser distance of the object