Radar power

Published : Feb 24, 2012 00:00 IST

THE BATTLEFIELD SURVEILLANCE Radar - Short Range, displayed inside the Electronics and Radar Development Establishment of the DRDO in Bangalore.-K. MURALI KUMAR

THE BATTLEFIELD SURVEILLANCE Radar - Short Range, displayed inside the Electronics and Radar Development Establishment of the DRDO in Bangalore.-K. MURALI KUMAR

The LRDE, a premier laboratory of the DRDO, develops a range of radar systems to meet the requirements of the defence forces.

THE scene is a bunker on the wooded campus of the Electronics and Radar Development Establishment (LRDE), one of the premier laboratories of the Defence Research and Development Organisation (DRDO), in Bangalore. A radar is positioned near the bunker's window to face the road. Its piercing eyes detect and track a man walking a few kilometres away and the image immediately looms into view on a computer monitor. When the moving target quickens its pace, the rhythm is reflected on the monitor. When a man is caught crawling a few 100 metres away, the image on the monitor captures the slow motion.

The man-portable, battery-operated Battlefield Surveillance Radar Short Range (BFSR-SR), has become a hit with the Army. Weighing just 30 kg, it can be brought into operation in a battlefield in about five minutes. It can detect, track and classify a variety of ground-surface targets within a detection range of 700 metres to eight kilometres. So far, 1,441 BFSRs have been delivered to the Army and 90 to the Border Security Force (BSF). Bharat Electronics Limited (BEL), Bangalore, manufactures this radar.

We developed the BFSR in two years to the specific requirements of the Army. The mandate was that it should be deployable in hilly, snow-bound high-altitude areas, should withstand very low temperatures, and be light in weight, said S. Varadarajan, Director, LRDE. There was a felt need during the Kargil conflict in 1999 to develop a short-range radar to alert the Army about enemy intrusions on high-altitude terrain.

Driving Rain Chamber, reads the quizzical legend on a box-like contraption in a building that houses the many-chambered Quality and Reliability Assurance Division on the campus. As the doors of the Driving Rain Chamber swing open, we find the central processing unit (CPU), the heart of a radar system, being drenched in the rain that issued forth from within the chamber. The CPU was being battered as part of the quality and reliability check to prove the radar's ruggedness. The CPU processes the data received by the radar, senses the target with the help of an antenna, and sends it for display. It can classify the enemy too.

The building contains Combined Altitude, Temperature and Humidity (CATH) chambers, thermal shock chambers, dust chambers, corrosion chambers, and so on, where the various parts of radars are tested thoroughly before the systems are deployed in the field. The thermal shock chamber has three compartments. In the cold compartment, the temperature ranges from -700 Celsius to +800 C and in the hot cell, it ranges from 00 C to 2000 C. The third compartment has ambient temperature. The airborne radar systems are tested in these temperatures because when an aircraft climbs to an altitude of 40,000 feet (12,000 metres), the transition time from the ambient temperature to freezing cold is only 10 minutes. The airborne radar systems should withstand these thermal shocks. Even the gear box of India's Light Combat Aircraft (LCA), Tejas, was tested in the CATH chambers.

The 60-foot long, 40-foot broad and 32-foot tall anechoic chamber was set up in 1987 to test the equipment on the Arjun battle tank and later that in Tejas and in India's nuclear-powered submarine, Arihant. It is now used to test the radar equipment. Any equipment should be compliant with electromagnetic interference [EMI], which cannot be eliminated, explained D.C. Pandey, Outstanding Scientist, LRDE, who is also India's foremost expert in EMI and electromagnetic compatibility (EMC). You can reduce the EMI to a particular level and that level depends on the platform [on which the equipment is integrated]. These platforms are ships, aircraft, submarines, satellites and the ground. In the anechoic chamber, the electromagnetic field is amplified and measured. We amplify the field and measure the effect, and make sure that the equipment is immune to the harsh electromagnetic environment, Pandey said.

With the radar systems undergoing such a battery of tests, it is not surprising that Varadarajan asserted: The radars, developed by the LRDE, are performance-wise on a par, if not better than, with the best in the world. The armed forces place repeat orders with BEL for a range of radars, including BFSR-SR, Rohini and Rajendra. Today, we are totally focussed on the development of radars for the three armed forces. We want the radars we develop to become globally competitive because the Army has the option to shop anywhere, he said. The LRDE has developed the primary radar for the indigenous Airborne Early Warning and Control System (AEW & CS), which helps in tactical missions against enemy aircraft or in deep penetration strikes. The AEW & CS was tested during its maiden flight on a modified Embraer aircraft in Brazil on December 6, 2011. Tejas uses the antenna developed by the LRDE.

W. Selvamurthy, Chief Controller (Life Sciences), DRDO, is proud of the galaxy of radar systems developed by the LRDE. They include the BFSR-SR; the weapons-locating radar (WLR) Swathi; the lightweight Bharani for the Army's air defence; Aslesha for the Indian Air Force (IAF); Rohini, the backbone of India's air defence; Revathi, the surveillance radar for the Navy; Rajendra, a phased-array radar, which is the core of Akash, India's surface-to-air missile system; the airborne maritime patrol radar, which has been integrated into India'a Advanced Light Helicopter; the Navy's Kamov-25 helicopter and the Coast Guard's Dornier aircraft; and the ground-penetration radar for locating buried mines, improvised explosive devices (IEDs) and unexploded ordnances (UXOs). BEL is the LRDE's production buddy for all the radars. The LRDE has now plunged into the development of a through wall looking radar, which can do remote three-dimensional (3D) imaging of terrorists hiding behind walls and detect even their heartbeats.

The DRDO, with 52 laboratories located in different parts of the country, is one of the largest enterprises of its kind catering to the Indian armed forces. Selvamurthy estimated that the production value of the products developed by the DRDO in the last eight years was around Rs.1,60,000 crore. The Army has placed orders for 124 Arjun-Mark I main battle tanks, developed by the DRDO's Combat Vehicles Research and Development Establishment (CVRDE) situated at Avadi near Chennai. Each Arjun tank cost Rs.18 crore, Selvamurthy said. The Army has placed orders for a batch of 124 Arjun-Mark II battle tanks too, which will feature a number of modifications on Mark-I. The IAF has placed orders for 40 Tejas aircraft, each costing more than Rs.150 crore.

Production orders in the past eight years for products developed by the DRDO to counter nuclear, biological and chemical warfare agents are valued at Rs.800 crore. They include gamma flash sensors, dosimeters, roentgenometers, reconnaissance vehicles, water purification filters, nerve-agent detectors and underground shelters.

In the field of radars, the DRDO's customers are well-defined: the Army, the Navy and the Air Force. The Army's requirements are demanding: the radars should be light enough to be transported and capable of being assembled or dismantled quickly.

Varadarajan said: Today, there is an inclination among the Services to use Indian radars because we match their requirements. The goal of our laboratory is to develop the key technologies required for radars, keeping in view the products required over the next decade, and to synergise a partnership between public sector and private units and quickly develop the products. This requires the right blend of engineering and electronics and an understanding of the specific environment in which the radars have to be deployed. LRDE engineers are engaged in concurrent engineering with their counterparts in the private sector. The LRDE is partnering a network of private units, which had invested in the development of specific subsystems, including microwave tube assemblies, fabrication of material needed for antennae, compact and rugged power packs, and cooling units.

Varadarajan said: These private units manufacture quality products needed for radars, benchmarking themselves against established foreign vendors. Today, these industries are able to design subsystems against stringent requirements by the armed forces. The net result is that there is a public-private sector partnership and the items produced in this country, particularly radars, remain globally competitive. We have been able to cut down the development time for many of the radars because we unearth private partners who can take part in the development, we adhere to concurrent engineering, and there is a mechanism for production. We are very much on track.

The roles of the various radars developed by the LRDE are impressive.

R. Kuloor, Outstanding Scientist, LRDE, explained that the BFSR located the position of the target with the help of electromagnetic waves and displayed the image of the target on the control and display unit. So the radar can be left unattended, he said. We can see the action in real time. As he was talking the audio Doppler picked up the sound of the siren of an ambulance that came within its range.

To detect aerial targets such as helicopters, unmanned aerial vehicles (UAVs), remotely piloted vehicles (RPVs) or fighter aircraft, the LRDE has designed a radar system called Bharani. The radar can be transported in a vehicle, as an under-slung of a helicopter, or on a mule. The Army was keen that this kind of short-range radar should be developed for deployment in mountainous terrain in Jammu and Kashmir and in the north-east region, M. Ramanjeneyulu, LRDE scientist, said.

Bharani weighs 165 kg and its petals can be assembled in 10 minutes. The Army has accepted the radar and it is under production. Bharani can be installed in any place, even in a bunker and in uneven places. It can withstand strong winds in hilly areas, Ramanjeneyulu explained.

The backbone of India's air defence is the vehicle-mounted Rohini medium-range radar, which can detect 200 targets simultaneously. It can detect fixed-wing aircraft flying at a distance of 200 km at a height of 18 km. It can be deployed and decamped in 30 minutes. If Sagar Samrat [the Oil and Natural Gas Corporation's offshore oil rig production platform] has to be protected against aerial attacks, we need this type of radars, Varadarajan said.

Revathi is a 3D medium-range radar installed on naval ships. It can detect sea-surface targets 80 km away, fighter-aircraft 150 km away, and cruise missiles at a distance of 40 km. The Tactical Control Radar (TCR), an avatar of Rohini, is built to suit the Army's requirements.

Any modern radar searches for, detects and tracks a target precisely and provides information on its speed and height. It does this by mechanical scanning or by rotating its antenna. In a phased-array radar, the requirements are even more stringent.

Rajendra boasts of an electronic scanning array. It can perform multiple functions it keeps surveillance over the sky, searches for the target, acquires it and tracks it. It can guide in real time 12 Akash missiles towards intruders until the warhead explodes. Rajendra can simultaneously do precision tracking of four targets. Its instrumented range is 80 km and height coverage is 18 km. It has an IFF system to identify a target as a friend or foe.

Rajendra is a success story. The Army and the Air Force have placed bulk orders for it, probably the biggest such orders. It has given a fillip to the Indian defence industry, said Varadarajan.

A derivative of Rajendra is Swathi, which was developed in the aftermath of the Kargil conflict. When shells are fired from an enemy artillery gun or mortar, the WLR will track their trajectory and thus identify the gun's location. It can locate, in a few seconds, large mortars positioned 20 km away and guns positioned 30 km away. This radar can see up to seven shells at the same time. The WLR, in its secondary role, can track the fall of shots from our own weapons to give corrections to our fire, said R.V. Narayana, Project Director of Swathi. Swathi went through extensive trials at the Army's test range in Pokhran in Rajasthan and its performance was found to be among the best in the world, he added. We went for concurrent engineering where the development, user and production agencies worked together from day one. Within two months of proving the prototype, the production model went for user trials, he said. Swathi has been cleared for production and is being inducted into the Army.

An ambitious programme under way is the development of the Arudhra radar system for the IAF. It has a rotating, electronic scanning array. It can detect intruding aircraft flying more than 300 km away and at altitudes ranging from 30 m to 30 km. Arudhra is vital for India's air defence and will be useful for network-centric warfare.

Under development against specific requirement is a low-level, transportable radar called Ashwini, for automatic detection and tracking of helicopters, fixed-wing aircraft, UAVs and RPVs. Ashwini will take the place of Rohini when the latter's production is completed.

The LRDE is developing a Coastal Surveillance Radar (CSR) to track shipping vessels, small boats and trawlers in rough sea and bad weather conditions. This is a challenging area, said Kuloor. The challenge is in resolution of small-sized, closely spaced targets in a sea clutter. The CSR can track even catamarans, which do not have a big radar cross section. The CSR's purpose is to track ultra-small objects, resolve and identify them, Kuloor added. The radar's coverage is 30 km.

Aslesha has been developed for deployment in high-altitude areas such as Leh and Kargil. The system was tested in -300 C in Leh. It has been designed in such a way that it can be deployed in a place where there is no human access, said Anil Kumar Singh, Scientist, LRDE, and Project Director, Aslesha. The radar can be assembled in 20 minutes without using a tool. Its various parts can be snapped together into place. It can be dismantled into small parts and transported. Aslesha has 18 antennae and its height coverage is 20,000 feet (6,000m). If it is installed on a hilltop, it can look down. If it is deployed in a valley, it can look up. What is special is that this radar is 100 per cent indigenous. All technologies [that went into its making] were developed in India, Anil Kumar Singh said. A fibre-optic cable connects the radar to the operator's computer in the bunker a kilometre away. It has an IFF system. The IAF has ordered the supply of 21 Aslesha radars.

Anil Kumar Singh, who is also Project Director for the Active Electronically Scanning Array (AESA) radar, called it an ambitious project. The project was approved in January. The main role of the radar, which will be integrated with the fighter aircraft, is to direct the fire accurately from the aircraft. It will feature advanced electronic counter, counter measures (ECCMs). The radar will direct the fire from air-to-air, air-to-ground and air-to-sea missiles.

We have taken a lot of initiatives to bring out several contemporary radars to meet the requirements of the Services, Varadarajan said.

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