The DRDO has steadily increased its radar development. The result has been substantial progress in India's ability to design and manufacture high power radar systems with locally sourced components and systems.
This began with the development of short-range 2D systems (Indra-1) and has now extended to high power 3D systems like LRTR intended for strategic purposes. Several other projects span the gamut of radar applications, from airborne surveillance (AEW&C) to firecontrol radars (land based and airborne)
. The DRDO's productionised as well as production-ready radar systems include:
INDRA series of 2D radars meant for Army and Air Force use. This was the first high power radar developed by the DRDO, with the Indra-I radar for the Indian Army, followed by
Indra Pulse Compression (PC) version for the Indian Air Force, also known as the
Indra-II, which is a l
ow level radar to search and track low flying cruise missiles, helicopters and aircraft. These are 2D radars which provide range and azimuth information and are meant to be used as gap fillers. The Indra 2 PC has pulse compression providing improved range resolution. The series are used both by the Indian Air Force and the Indian Army[35]
Rajendra fire control radar for the Akash SAM: The Rajendra is stated to be ready. However, it can be expected that further iterative improvements will be made. The Rajendra is a high power Passive electronically scanned array radar (PESA), with the ability able to guide up to 12 Akash SAMs against aircraft flying at low to medium altitudes. The
Rajendra has a detection range of 80 km with 18 km height coverage against small fighter sized targets and is able to track 64 targets, engaging 4 simultaneously, with up to 3 missiles per target. The Rajendra features a fully digital high speed signal processing system with adaptive moving target indicator, coherent signal processing, FFTs and variable pulse repetition frequency. The entire PESA antenna array can swivel 360 degrees on a rotating platform. This allows the radar antenna to be rapidly repositioned and even conduct all round surveillance.[36]
Central Acquisition Radar, a state of the art planar array S-Band radar operating on the stacked beam principle. With a range of 180 km, it can track while scan 200 fighter sized targets. Its systems are integrated on high mobility, locally built TATRA trucks for the Army and Air Force; however it is meant to be used by all three services. Initially developed for the long-running Akash SAM system, seven were ordered by the Indian Air Force for their radar modernization program and two of another variant were ordered by the Indian Navy for their P-28 Corvettes. The CAR has been a significant success for radar development in India, with its state of the art signal processing hardware.[37][38] The ROHINI is the IAF specific variant while the REVATHI is the Indian Navy specific variant. The ROHINI has a more advanced Indian developed antenna in terms of power handling and beamforming technology while the REVATHI adds two axis stabilisation for operation in naval conditions, as well as extra naval modes.
BFSR-SR
BFSR-SR, a 2D short-range Battle Field Surveillance Radar, meant to be manportable. Designed and developed by LRDE, the project was a systematic example of concurrent engineering, with the production agency involved through the design and development stage. This enabled the design to be brought into production quickly.[39][40] The radar continues to progress further in terms of integration, with newer variants being integrated with thermal imagers for visually tracking targets detected by the radar. Up to 10 BFSR-SR can be networked together for network centric operation. It is in use with the Indian Army and the BSF as well as export customers.
Super Vision-2000, an airborne 3D naval surveillance radar, meant for helicopters and light transport aircraft. The SV-2000 is a lightweight, high performance, slotted array radar operating in the X Band. It can detect sea-surface targets such as a periscope or a vessel against heavy clutter and can also be used for navigation, weather mapping and beacon detection. The radar can detect a large vessel at over 100 nautical miles (370 km). It is currently under modification to be fitted to the Advanced Light Helicopter and the Navy's Do-228's. Variants can be fitted to the Navy's Ka-25's as well.[41] The radar has been inducted by the Indian Navy and a more advanced variant of the Super Vision, known as the XV-2004 is also operational, and features an ISAR, SAR Capability.
Swordfish Long Range Tracking Radar, a 3D AESA was developed with assistance from Elta of Israel and is similar to Elta's proven GreenPine long-range Active Array radar. The DRDO developed the signal processing and software for tracking high speed ballistic missile targets as well as introduced more ruggedization.
The radar uses mostly Indian designed and manufactured components such as its critical high power, L Band Transmit-Receive modules and other enabling technologies necessary for active phased array radars. The LRTR can track 200 targets and has a range of above 500 km. It can detect Intermediate-range ballistic missile. The LRTR would be amongst the key elements of the Indian Ballistic Missile Defense Program. DRDO would provide the technology to private and public manufacturers to make these high power systems.[42]
3D Multi Function Control Radar (MFCR) was developed as part of the Indian anti-ballistic missile program in cooperation with THALES of France. The MFCR is an active phased array radar and complements the Swordfish Long Range Tracking Radar, for intercepting ballistic missiles. The MFCR will also serve as the fire control radar for the AAD second tier missile system of the ABM program. The AAD has a supplementary role against aircraft as well and can engage missiles and aircraft up to an altitude of 30 km. The MFCR fills out the final part of the DRDO's radar development spectrum, and allows India to manufacture long-range 3D radars that can act as the nodes of an Air Defence Ground Environment system.
2D Low Level Lightweight Radar (LLLR) for the Indian Army, which requires many of these units for gapfilling in mountainous terrain. The Indian Air Force will also acquire then for key airbases. The LLLR is a 2D radar with a range of 40 km against a 2 square meter target, intended as a gapfiller to plug detection gaps versus low level aircraft in an integrated Air Defence Ground network. The LLLR makes use of Indra-2 technology, namely a similar antenna array, but has roughly half the range and is much smaller and a far more portable unit. The LLLR can track while scan 100 targets and provide details about their speed, azimuth and range to the operator. The LLLR makes use of the BFSR-SR experience and many of the subsystem providers are the same. Multiple LLLRs can be networked together. The LLLR is meant to detect low level intruders, and will alert Army Air Defence fire control units to cue their weapon systems.[43]
3D Short Range Radar for the Indian Air Force - ASLESHA: The ASLESHA radars have a range of approximately 50 km against small fighter-sized targets and will be able to determine their range, speed, azimuth and height. This radar will enable the Indian Air Force Air Defence units to accurately track low level intruders. The radar is a semi-active phased array with a 1 meter square aperture. The DRDO was in discussions with the Indian Navy to mount these systems on small ships.
Multi-mode radar, a 3D radar is a HAL project with DRDO's LRDE as a subsystem provider. This project to develop an advanced, lightweight Multimode fire control radar for the LCA Tejas fighter had faced challenges and was delayed. It has now been completed with Elta's (Israel) assistance. The multimode radar has range (for detection of a small fighter target) greater than 100 km, can track 10 targets, can engage 2 targets and uses lightweight system. It has been revealed that an all new combined signal and data processor had been developed, replacing the original separate units. The new unit is much more powerful and makes use of contemporary ADSP processors. The radar's critical hardware has also been developed and validated. The software for the air to air mode has been developed considerably (including search and track while scan in both look up and look down modes) but air to ground modes are still being worked upon. The radar development was shown to be considerably more mature than previously thought. At Aero India 2009, it was revealed that the 3D MMR project has been superseded by the new 3D AESA FCR project led by LRDE. The MMR has been completed with Elta Israel's assistance and now involved Elta EL/M-2032 technology for Air to Ground mapping and targeting. This "hybrid" MMR has been tested, validated and will be supplied for the initial LCA Tejas fighters.
DRDO has indigenised components and improved subsystems of various other license produced radars manufactured at BEL with the help of BEL scientists and other researchers. These improvements include new radar data processors for license produced signal radars as well as local radar assemblies replacing the earlier imported ones.
Apart from the above, the DRDO has also several other radar systems currently under development or in trials, these include:
BEL Weapon Locating Radar:
A model of the BEL Weapon Locating Radar A 3D radar successfully developed from the Rajendra fire control radar for the Akash system, this radar uses a passive electronically scanned array to detect multiple targets for fire correction and weapon location. The system has been developed and demonstrated to the Army and orders have been placed[44] In terms of performance, the WLR is stated to be superior to the AN/TPQ-37, several of which were imported by India as an interim system while the WLR got ready.
Active Phased Array radar: a 3D radar for fighters, a MMR follow on, the APAR project aims to field a fully fledged operational AESA fire control radar for the expected Mark-2 version of the Light Combat Aircraft. This will be the second airborne AESA program after the AEW&C project and intends to transfer the success DRDO has achieved in the ground based radar segment to airborne systems. The overall airborne APAR program aims to prevent this technology gap from developing, with a broad based program to bring DRDO up to par with international developers in airborne systems, both fire control and surveillance.
Synthetic aperture radar & Inverse synthetic aperture radar: the DRDO's LRDE is currently working on both SAR and ISAR radars for target detection and classification. These lightweight payloads are intended for both conventional fixed wing as well as UAV applications.
Airborne Warning and Control: a new radar based on Active Electronically Scanned Array technology. The aim of the project is to develop inhouse capability for high power AEW&C systems, with the system covering the development of a S Band AESA array. The aircraft will also have datalinks to link fighters plus communicate with the IAF's C3I infrastructure as well as a local SATCOM (satellite communication system), along with other onboard ESM and COMINT systems.[45]
Medium Range Battlefield Surveillance Radar: in 2009, the LRDE (DRDO) noted that it was working on a Long-range battlefield surveillance radar. It is possible that the BFSR-LR project has replaced this earlier project and the Indian Army will utilize the BEL built ELTA designed BFSR-MR's for Medium Range surveillance while using the LRDE designed systems for Long Range surveillance. The 2D radar will track ground targets and provide key intelligence to the Indian Army's artillery units, with the resultant information available on various tactical networks.
3D Medium Power Radar: a spinoff of the experience gained via the 3D MFCR project, the 3D Medium Power Radar project is intended to field a radar with a range of approximately 300 km against small fighter sized targets. Intended for the Indian Air Force, the radar is an active phased array, and will be transportable. It will play a significant role being used as part of the nodes of the Indian Air Force's enhanced Air Defence Ground Environment System.
3D Tactical Control Radar: a new program, the TCR is an approximately 150 km ranged system for use by the Indian Army and Air Force. A highly mobile unit, it will also employ open architecture to provide easy upgrades, and a variety of modes and capabilities depending on the software fit. The aim of the 3D Medium Power Radar and TCR is to offer systems which can be deployed in a variety of roles, from fire control to surveillance, and not be tied to one role alone.