# Uttam AESA Radar

Uttam (lit. 'Greatest') is a solid-state gallium arsenide (GaAs) based AESA radar under development by the Electronics and Radar Development Establishment (LRDE), a laboratory of the Indian Defence Research and Development Organisation (DRDO). It is a low probability of intercept radar. It is a 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 radar development began in 2012 and 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 major supplier of subsystems. As per Project director D Seshagiri of Electronics and Radar Development Establishment (LRDE), 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. Uttam AESA Radar was authorized for export from 2023.

### 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.
As of April 2024, the radar has completed 125 test sorties onboard Tejas Mk 1 prototypes as per ADA Director Dr 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.

## Features

* Full solid-state (electronics) radar, based on GaAs
* High MTBCF (redundancy)
* Range: >100 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
* 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.

## Virupaakhsha

Virupaaksha radar is an advanced version of the Uttam Mk-II radar. The radar under development will replace the current N011M Bars radar being used onboard the Sukhoi Su-30MKI after the Super Sukhoi upgrade program. Virupaakhsha weighs half as much as the N011M Bars. The LRDE was working on the project, but got approval in October 2024. LRDE plans to set up "assembly jigs" to begin ground testing soon. These will be delivered within 16 weeks of the contract’s approval. The assembly will be completed within 15 weeks while the last week will be reserved for acceptance testing.
Virupaaksha utilises Gallium Nitride (GaN) technology with improved radar operational characteristics than Gallium Arsenide (GaAs) used by earlier variants. GaN provides better power output, enhanced thermal efficiency, wider bandwidth of operation, and a longer lifespan compared to earlier variants. The radar incorporates the quad transmit-receive modules (T/R modules) similar to Uttam but has a more densely packed configuration and has around 2400 modules based on GaN based planks. The plank configuration eases maintenance operations. Reportedly, the radar succeeded to track 64 to 100 aerial targets simultaneously during trials and offers at least 1.7 times increased head-on search range over the 140 km-range N011M Bars radar. It features advanced electronic counter-countermeasures (ECCM). The Virupaksha radar operates in the S-band frequency range, and can detect and track a wide range of targets like aircraft, helicopters, drones, and even ballistic missiles. It has a reported head-on search range of over 400 km, though the value is officially classified. In air-to-air attack mode, Virupaakhsha can maneuver, control, and direct six missiles simultaneously towards the target.

## Applications

The fighter jet platforms that have been integrated with Uttam radar or are planned to be integrated are as follows:
* HAL Tejas Mk1/1A (Testing phase): Already integrated on Limited Series Production aircraft (LSP 2 and 3). They have completed 125 developmental flights. The radar will be directly integrated on Tejas Mk1A from the 41st production aircraft onwards.
* Hawker 800 (Testing phase)
* HAL Tejas Mk 2 (more capable version planned)
* Sukhoi Su-30MKI (Planned from 2025): During the Super Sukhoi upgrade, the present PESA Bars radar will be replaced by the Virupaaksha radar. In the first phase, 84 units would be upgraded by Hindustan Aeronautics Limited (HAL) in India.
* Mikoyan MiG-29UPG/Mikoyan MiG-29K (Planned from 2025)
* HAL TEDBF (Planned)
* HAL AMCA (Virupaaksha variant planned)

## Gallery

* Uttam AESA Radar integrated in LCA Tejas showcased during Aero India 2019.
* Uttam AESA radar on display at Aero India 2019
* Side profile of Uttam AESAR.
* The Active Antenna Array Unit (AAAU) of Uttam AESA radar on static display at Aero India, 2019