How Radars system works ?


Radars (radio detection and ranging) is a detection system that uses radio waves to determine the distance, angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. Its system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the objects. Radio waves from the transmitter reflect off the objects and return to the receiver, giving information about the objects locations and speeds.

In India, Electronics and Radar Development Establishment (LRDE) is the laboratory that comes under Defence Research & Development Organisation ( DRDO ) which is responsible for development of radars. This organisation has met success with various radar systems developed by it being inducted in Indian Armed Forces now in large numbers.

INDRA Radars

Indra radars

The Low Flying Detection Radar also called Indian Doppler Radar (INDRA) series of 2D radars were developed by Electronics and Radar Development Establishment (LRDE), of Defence Research and Development Organisation (DRDO) for the Army and the Air Force. These were then produced by Bharat Electronics which is generally the production partner of LRDE. The INDRA-I is a mobile surveillance radar for low level target detection while the INDRA-II is for ground controlled interception of targets which is a variant of INDRA radar for ground controlled interception of targets. It uses pulse compression for detection of low flying aircraft in heavy ground clutter with high range resolution and ECCM capabilities.


Rajendra radars

Rajendra is a passive electronically scanned array radar developed by the Defence Research and Development Organisation (DRDO). It is a multifunction radar, capable of surveillance, tracking and engaging low radar cross section targets. It is a ground surveillance radar and is a great source of surveillance operating at frequency around 20 GHz. It is mainly used to track enemy’s installations. It is named after India’s First president Dr. Rajendra Prasad.

The LRDE is working on the Rajendra III radar for the Indian Army which is a slewable phased array radar based on the T-72 chassis built by Ordnance Factories Board’s Ordnance Factory Medak.


Rohini radars

The Rohini is an S-Band ground based 3D medium range air surveillance radar providing detection and tracking air targets even under hostile EW operational environments. It is capable of handling multiple targets simultaneously and also precisely calculates the height at which projectiles are flying. Mounted on Tatra mobile platform, a heavy duty modified truck built by the public sector Bharat Earth Movers Limited (BEML) and supported by an auxiliary mobile power unit, it enables the Rohini to be easily transported to the battlefront.

Operating in a range of up to 170 kilometres and an altitude of 15 kilometres, the Rohini radar can track multiple targets like fighter jets and missiles travelling at supersonic speeds of over 3,000 km per hour. It employs an array of Electronic Counter CounterMeasure (ECCM) features including frequency agility and jammer analysis. A Secondary Surveillance Radar, which distinguishes friendly and hostile aircraft. About 100 pieces are expected to be built, with around 20 radars being manufactured every year.


Swathi radars

The Weapon Locating Radar (WLR) also known as Swathi is a mobile artillery-locating phased array radar developed by India. This counter-battery radar is designed to detect and track incoming artillery and rocket fire to determine the point of origin for counter-battery fire.

The WLR has been jointly developed by the Electronics and Radar Development Establishment (LRDE), a lab of the Defence Research and Development Organisation (DRDO) and Bharat Electronics Limited (BEL). The sub-systems have been fabricated by BEL based on the DRDO designs and delivered to LRDE for integration



India’s first indigenously-developed balloon-mounted radar that will greatly enhance the surveillance capabilities of the armed forces has been successfully launched.

The aerostat radar was launched from a military compound and will remain at a height of about one kilometre for the next two or three days.The helium-filled aerostat has night vision cameras and sound recorders, weighs around 300 kg, and can be reused.

The aerostat will be used for communication and surveillance. The platform integrates high-end technology, aerodynamics, balloon techniques, hydraulics and high-pressure cylinder technology, according to the scientists involved in the project.

The Indian army and the Indian air force hitherto rely on Israeli aerostats that are deployed along the country’s western borders but the Indian version would be a cheaper option. They supplement the efforts of the air force’s airborne warning and control systems (AWACS) that fly at a much greater height.

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