In this lecture we are going to learn about, Introduction of Radar, the Type of Radar, How Radar is working, the Working Principle of Radar, Components used in the Radar system, Application of Radar. So let’s discuss each topic one by one in a detailed manner. but before starting to know about the Radar let’s discuss its introduction part and then we will move to its technical part.
Introduction of Radar
- Radar is an acronym for “Radio Detection and Ranging”.
- The term Radio refers to the use of electromagnetic waves with a wavelength in the so-called radio waves of the spectrum, which covers a wide range from 104 km to 1 cm.
- A radar is a system used to detect, determine the distance and map the objects such as aircraft and rain.
- Radar uses strong radio waves for transmitting and the receiver listens for reflected echoes.
- By analyzing the reflected signal, the reflector(object) can be located and identified.
- Radar can operate in darkness, haze, fog, rain, and snow. it has the ability to measure distance with high accuracy in all weather conditions.
Working Principle of Radar
- The electronics principle on which Radar operates is very similar to the principle of sound wave reflection.
- If you shout in the direction of sound-reflecting objects, you will hear an echo. So if you know the speed of sound in the air, then estimate the distance and general direction of the object.
- Same, Radar uses electromagnetic energy pulses. The radio frequency energy is transmitted to and reflects from the reflecting object.
- A small portion of the energy is reflected and returned to the Radar system. This returned energy is called an ECHO.
- Radar systems use the echo to determine the direction and distance of the reflecting object.
Block Diagram of Radar
A practical Radar system requires the seven Basic components as illustrated in the figure:
1. Transmitter
- The transmitter makes the electromagnetic wave be sent and adjusts it from the beat train. The transmitter should likewise enhance the sign to a strong level to provide sufficient reach. The wellspring of the transporter wave might be a Klystron, traveling wave Tube (TWT), or Magnetron. Everyone has their own qualities and restrictions.
2. Receiver
- The receiver is sensitive to the range of frequencies being transmitted and provides amplification of the returned signal. so as to supply the best range, the receiver must be very sensitive without introducing excessive noise. the flexibility to discern a received signal from a background signal depends on the signal-to-noise ratio(S\N).
3. Power Supply
- The power supply provides the electric power for all the components. the most important consumer of power is the transmitter, which can require several kW of power. The actual power transmitted within the pulse could also be much greater than 1 kW.
- The power supply only must be ready to provide the typical amount of power consumed, not the high power level during the particular pulse transmission.
4. Synchronizer
- The Synchronizer syncs the timing for the range determination.
- Synchronizer sent the signal along with the transmitted signal to know the return sweep and display the signal.
5. Duplexer
- This is act like a switch between the transmitter and receiver.
- Duplexer place to minimize to use of the different antennae for transmitter and receiver.
- During the transmission of the pulse, the duplexer will align for the transmitter, and after the pulse is sent, the duplexer will align the antenna to the receiver.
- Duplexers also use to protect the receiver from high power output from the transmitter.
6. Antenna
- The antenna basically acts as a mediator between the system and the air.
- The antenna takes the Radar pulse from the transmitter and puts it into the air, and also takes the reflected wave from the air and puts it into the receiver.
- The antenna used in Radar systems is highly directional with low beam width.
7. Display
- Display units are basically used to represent the object on the screen to analyze the object easily.
- there are various types of displays available in the Radar systems like A-scope, B-scope, PPI, etc.
- A-scope is the most basic type of display which is used to display the range of the object but can’t provide the direction of the object.
- PPI is the most common display. It named as Plan Position Indicator
Read More about: Types of Display
Different Types of Radar:
Radar systems may be divided into types based on the designed use. This section represents the general characteristics of several commonly used Radar systems.
- Air-Defense Radar
- Air Traffic Control Radar
- Fire Control radar or Tracking Radar
- Speed Gauge
- Airborne Radar
- Motor Locating Radar
- Radar Satellites
- weather Radar
- Ground Penetrating Radar
Depending on the desired information, radar units must have different qualities and technologies.
The reason of these different qualities and techniques of radar units are classified is:
Primary Radar
- A primary Radar transmits high-frequency signals which are reflected at targets.
- The received echoes are evaluated.
- Primary Radars are transmitted and receive echo signals.
Secondary Radar
- Secondary Radar signals only Transmit the signal. The airplane has a transponder on board to receive an encoded signal from the secondary radar.
- An example of secondary radar is IFF (identification of Friend and Foe).
Pulsed Radar
- Pulse radar units transmit a high-frequency impulsive signal of high power. After a longer break in which the echoes can be received follows before a new transmitted signal is sent out.
- Direction, Distance, and sometimes if necessary the altitude of the target can be determined from the measured antenna and propagation time of the pulse signal.
Continuous-Wave Radar (CW Radar)
- CW Radar units transmit a high-frequency signal continuously. The echo signal permanently is received and processed.
- The receiver need not be mounted at the same place as the transmitter.
Read More: Frequency Modulated CW radar
Unmodulated CW Radar
- The transmitter signal of this equipment is constant in amplitude and frequency. These equipment are specialized n speed measuring. The distance cannot be measured.
Modulated CW-Radar
- The transmitted signal is constant in amplitude but modulated in frequency.
- It is the advantage of this equipment that an evaluation is carried out without a reception break and measurement is continuously available.
- These radar units are used everywhere
Application of Radar
- Surveillance search Radar in military
- Navigational Radar in the military as well as in civil
- Targeting Radar or tracking Radar
- Weather Radar
- Radar proximity fuses
- Radar altimeter
- Air traffic control Radar
- Traffic Radar.
- Monitoring of space vehicles.
- In the industry of oil and gas exploration.
Radar Frequencies and its Applications
| Frequency | Description | Application |
|---|---|---|
| Up to 300Hz | Extremely Low Frequency (ELF) | Special Communication |
| 300Hz – 3KHz | Voice Frequency | Ship and shore long-range communication |
| 3KHz – 30KHz | Very Low Frequency (VLF) | Shored-based communications, experimental |
| 30KHz – 300KHz | Low Frequency (LF) | Shored-based communications, navigation |
| 300KHz – 3MHz | Medium Frequency (MF) | commercial broadcast band |
| 3MHz – 30MHz | High Frequency (HF) | Ship and shore long range communication |
| 30MHz – 300MHz | Very High Frequency (VHF) | communication, navigation |
| 300MHz – 3GHz | Ultra High Frequency (UHF) | Line-of-sight communication to 400Mhz, above this frequency radar and special equipment |
| 3GHz – 30GHz | Superhigh Frequency (SHF) | radar and special equipment |
| 30GHz- 300GHz | Extremely High Frequency (EHF) | radar and special equipment |
FAQs
How does radar work?
The basics of radar is that a beam of energy, called radio waves, is emitted from an antenna. As the waves strike objects in the atmosphere, the energy is scattered in all directions, with some of the energy reflected directly back to the radar.
What is the basic concept of radar?
RADAR stands for Radio Detection and Ranging System. It is basically an electromagnetic system used to detect the location and distance of an object from the point where the RADAR is placed
Which wave is used in radar?
Radar systems transmit electromagnetic or radio waves.
What are the 5 main components of radar?
Radar systems are composed of physical elements: an antenna, duplexer, transmitter, receiver, controller, and display.
What is radar and its working principle?
RADAR is an electromagnetic-based detection system that works by radiating electromagnetic waves and then studying the echo or the reflected back waves.
