Range of radars

Print edition : December 18, 2009

Revathi, a 3D, medium-range surveillance radar, mounted on a naval vessel.-PHOTOGRAPHS; DRDO

THE Electronics and Radar Development Establishment (LRDE) in Bangalore has been spearheading the development of radar systems and related technologies for the defence forces. A Ministry of Defence research laboratory under the Defence Research and Development Organisation (DRDO), the LRDEs genealogy goes back to the Inspectorate of Scientific Stores set up in 1939 at Rawalpindi.

In 1946, it was re-designated as the Technical Development Establishment (Instruments and Electronics) and relocated in Dehradun. The electronics component was relocated to Bangalore in 1962 and the LRDEs role was redefined to develop indigenous and state-of-the-art military radar and communication systems. Today the LRDE is a premier radar systems laboratory with a core competence to build advanced systems in the L to X bands.

According to S. Varadarajan, Director, LRDE, the laboratory develops a range of products from short- to long-range sensors for ground, air and sea surface surveillance, tracking, and weapons control. Besides this, the LRDE has developed advanced radar technologies, including transmit and receive (TR) modules, slotted waveguide array antenna, high-power transmitters, programmable signal and data processors, radar controllers and multi-beam antenna.

The LRDE was roundly criticised for not successfully developing, in collaboration with Hindustan Aeronautics Limited, the multi-mode radar for the Light Combat Aircraft Tejas. But the Israeli radar now being fitted on the Tejas has an antenna designed by the LRDE the slotted waveguide array antenna. The LRDE is also undertaking the design and development of the active electronically scanned array (AESA) technology. The AESA technology allows ships and aircraft to broadcast powerful radar signals while they themselves remain under stealth. The AESAs basic building block is the TR module, a self-contained, miniaturised transmitter and receiver that makes up one of the AESA antenna elements. In a bid to develop the AESA, the LRDE has developed L and S band TR modules.

According to B.V. Ramesh, project director of LRDEs LSTAR programme, an LRDE-developed X-band AESA radar could be fitted on the Tejas by 2014. Two modules of the AESA radar have already been launched. Ramesh also disclosed that the LSTAR (Long-range Solid State Active Phase Array Radar), which is a sort of a forerunner to Indias Airborne Early Warning and Control System programme, has been approved by the Centre for Military Airworthiness and Certification, integrated and tested on ground-based systems, and qualified for airborne applications. And a production agency, Astra Microwave, has been identified for it.

Among the LRDEs foremost products is Indra-1, a radar that works on the Doppler principle. It has a 50-km range and is integrated with the fire control radar. It is in deployment with the Army and the Indian Air Force (IAF) as part of their air defence network. Indira-2, an improvement over Indira-1, was designed as per the needs of the IAF, which wanted a radar that can identify dense-formation targets, such as a group of aircraft flying wing tip to wing tip, and can be used even at high altitudes.

Bharani, a portable, short-range, light-weight radar. It provides 2D surveillance, mainly in mountainous terrain, against aerial targets.-

The LRDEs portable Battle Field Surveillance Radar (BFSR) - Short Range was developed after the Kargil conflict, when the inadequacies of binoculars were felt. An all-weather, automated detection of intrusions system was needed. Over 1,400 BFSRs are now being used by the Army against moving surface targets. A BFSR radar that offers foliage penetration is under development. The LRDE has also developed a coherent, electronically scanned C-Band Doppler Weapon Locating Radar for use by the Artillery Corps. Rohini is a 3D, medium-range, vehicle-mounted surveillance radar that offers 360 degree coverage and has a range of 150 to 180 km, and is used against low-, medium- and high-flying targets. It can measure the range, azimuth and the height of the target. It is designed for the IAF and will also be part of the Akash missile system. The LRDE is also developing the Revathi, a 3D, medium-range surveillance radar that will give the Navy cover against air and sea targets.

An off-shoot of the Rohini is the Aslesha, a 3D low-level, light-weight radar designed for use in mountainous terrain and against aerial targets. The LRDE developed this radar when the Army wanted a system that could be transported by animals. It has been evaluated at 15,000 feet (4,572 metres) and cleared for induction. The Bharani is another portable, short-range, low-level, light-weight radar. It provides 2D surveillance, mainly in mountainous terrain, against aerial targets such as unmanned aerial vehicles, helicopters and fixed-wing aircraft flying at low and medium altitudes.

The Rajendra, a multi-function, phased array radar, is the primary sensor at the battery level for the Akash weapon system, which is to be used for air defence by the IAF and the Army. It can perform extensive searches, track multiple targets and missiles, and command and guide multiple missiles concurrently. Says Varadarajan: It can be mounted on a T-52 tank bed or as per the IAFs requirements on a low-bed trailer.

Having realised the importance of timelines and technology obsolescence in the development of radar systems, the LRDE has decided to knit the user with the programme at the design stage itself. Says Varadarajan: An early association of the user helps fasten the programme. As for production, we want to be involved only with critical design and system engineering, capturing the users requirements. It is for industry to realise the prototype, prove the concept and also be the lead integrator.

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