Uttam (lit. 'Excellent') is a solid-state gallium arsenide (GaAs) based AESA radar under development by the Electronics and Radar Development Establishment, a laboratory of the Indian Defence Research and Development Organisation. It is an LPI (Low Probability of Intercept) liquid cooled AESA radar featuring quad-band modules that can be stacked to form a larger unit. The Uttam Mk-1 has a total of 912 TRMs.
Development The project was initiated in 2008, and the development began in 2012. Its full-scale model was displayed at the 2017 Aero India air show and aviation exhibition. People who worked for DRDO AEW&CS's main radar and Maritime Patrol Radar were part of the project team. A fully functional active electronically scanned array (AESA) radar prototype was unveiled at Aero India 2019, the prototype was mounted inside the glass nose of a HAL Tejas prototype. Hindustan Aeronautics Limited is the lead integrator and Bharat Electronics is the major supplier of subsystems. As per Project director D Seshagiri of the Electronics and Radar Development Establishment, Uttam AESA radar is 95% indigenous, with only one imported subsystem. The National Flight Testing Centre had evaluated the radar and cleared it after performance tests. The integration problem of Astra BVRAAM due to older generation of radars will also be solved by Uttam. During Aero India 2021, there was a licensing agreements for technology transfer from DRDO to Hindustan Aeronautics Limited for manufacturing and integration of the Uttam in the Mark 1A variant of the HAL Tejas. The technology transfer to HAL was finished by DRDO in July 2023, and the radar was approved for export as well. HAL placed an order for 122 Active Antenna Array Units and 121 Interface Frames for the Uttam Radar with Astra Microwave Products Limited on 31 July 2026, for ₹2,205 crore (US$230 million). According to reports, the second batch of 97 Tejas Mk1A aircraft would be equipped with the radar. Astra Microwave plans to finish the delivery by 2031.
Testing As of 2021, three units were in various phases of testing. The Uttam radar has completed 230 hours of airborne testing onboard two Tejas fighter jets (LSP2 and LSP3) and on an executive jet; presumed to be DRDO's Dornier 228 "Nabhratna" used as a flying test bed by LRDE. Once fully validated and certified, it is planned is to introduce the radar in later batches of Tejas Mark 1A aircraft. The Uttam radar will be used with DRDO's Unified Electronic Warfare suite. Indian Air Force Test Pilot School would start final demonstration trial of Uttam AESA radar from December 2021 and if successful will be sent for serial production. LRDE has completed 250 hours of performance testing on two Tejas fighters as well as Hawker 800 executive jet. The flight evaluation of the radar aboard Tejas Mark 1 is over, and the Uttam radar has successfully completed flight testing in all modes. In 2023, an updated Uttam radar was developed and placed on Limited Series Production aircraft in order to satisfy Tejas Mark 1A requirements. The Uttam radar was modified with an Active Array Antenna Unit and flight tested in Air to Air mode of operation for maximum range in July 2023. As of April 2024, the radar has completed 125 test sorties onboard Tejas Mk 1 prototypes as per ADA Director Jitendra Jadhav. The radar has cleared testing Air to Air (A2A) and Air to Ground (A2G) modes while few more tests are yet to be conducted. The performance of the radar is on par with other proven designs like EL/M-2052. In April 2025, Centre for Military Airworthiness and Certification informed HAL and DRDO internally that the Uttam radar had finished four stages of flight testing. Furthermore, the radar hardware has passed qualification tests in accordance with the specifications of the Tejas Mark 1A. CEMILAC suggested that construction of the radar subsystems be started in order to facilitate the induction of the radar, with the principal system integrator being Hyderabad based HAL's avionics division.
Features Full solid-state (electronics) radar, based on GaAs High MTBCF (redundancy) Range: >150 km Multi Target Tracking (50 Targets), Priority Tracking (4 Targets). Simultaneous operation modes. Solid-state, active phased array technology Pulse Doppler, all aspect, shoot down capabilities Simultaneous multi-target tracking and engaging Simultaneous multi-mode operation High ECM immunity Electronic counter-countermeasure Ultra-low side-lobe antenna Flexible interfaces allowing scalable design. Modular hardware and software Fast-beam agile system Quad band TRM modules pack High mission reliability (built with redundancy) IFF modes. C-band LOS, Ku band satcom link.
Operational Modes Uttam AESA radar has a total of 18 modes in Air to Air, Air to Ground and Air to Sea roles. The modes have been validated on-board a business jet and further proofing is being done on HAL Tejas to validate the same on supersonic platform.
Air-to-Air TWS/Multi-target detection and tracking Multi-target ACM High resolution raid assessment Air-to-Ground High resolution imaging (SAR Mode) High resolution tracking (SAR Mode) AGR – Air-to-Ground Ranging RBM – Real Beam Map DBS – Doppler Beam Sharpening GMTI on RBM, SAR Weather Air-to-Sea High resolution imaging (SAR Mode) High resolution tracking (SAR Mode) Sea search and multi-target tracking RS and ISAR classification modes.
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