Indian Air Force wants GaN-based indigenous AESA radar on the Russian Su-57 stealth fighter

The Indian Air Force is reportedly exploring a conditional path toward operating the Sukhoi Su-57 stealth fighter—but with one crucial requirement: replacing key Russian avionics with an indigenous digital architecture. At the center of this demand is a next-generation Gallium Nitride (GaN) based Active Electronically Scanned Array radar, expected to be derived from India’s upcoming Virupaksha AESA Radar.

For Indian defence planners, the debate is not simply about radar performance. It is fundamentally about “software sovereignty”—the ability to control mission systems, weapons integration, and future upgrades without relying on foreign source codes. Many modern fighter jets operate under a so-called “black box” model, where the manufacturer retains control over key software layers. This limits the operator’s ability to integrate new sensors or weapons independently.

By insisting on an Indian radar, mission computer, and electronic warfare suite, the IAF aims to ensure that a potential Su-57 fleet can seamlessly operate indigenous weapons such as the Astra Mk3 and the compact supersonic cruise missile BrahMos-NG. Without access to the aircraft’s core software architecture, integrating such systems could otherwise require lengthy negotiations with the original manufacturer.

The mission computer plays a decisive role in this architecture. Often described as the “brain” of a fighter aircraft, it manages sensor fusion, weapon targeting, and communication between subsystems. If this core element remains under foreign control, the aircraft’s operational flexibility becomes restricted. That is why Indian planners are pushing for a domestically controlled digital backbone that can accommodate not only Indian systems but also sensors sourced from allied partners in the future.

AESA Radar Technology Comparison: Russian vs. Indian Systems

Why the N036 Byelka Falls Short for the IAF

The Su-57 currently uses the N036 Byelka AESA radar, which relies on Gallium Arsenide (GaAs) semiconductor technology. While advanced when first introduced, GaAs arrays are gradually being replaced worldwide by Gallium Nitride systems due to their higher efficiency and improved power output.

Key differences between the two technologies help explain why the IAF prefers a GaN solution:

• Power Efficiency: GaN modules can operate with significantly higher power density while consuming less energy, making them more suitable for modern sensor-intensive combat aircraft.
• Thermal Signature: GaAs radars typically produce more heat, requiring larger cooling systems that can affect aircraft design and infrared visibility. GaN radars generate less thermal load, a critical factor for stealth platforms.
• Electronic Warfare Resistance: GaN technology enables stronger electronic counter-countermeasure (ECCM) capabilities, allowing radars to function effectively in heavily jammed environments.
• Future Upgrades: A domestically controlled radar architecture allows India to integrate new signal-processing algorithms without relying on external vendors.

These advantages align closely with India’s long-term air combat doctrine, which emphasizes networked warfare and deep-strike capabilities across both western and eastern theatres.

Virupaksha: Scaling the Super Sukhoi Radar for Stealth

The radar being considered for the Su-57 is not an entirely new design. The Virupaksha AESA Radar is already being developed as part of the “Super Sukhoi” upgrade program for the Sukhoi Su-30MKI fleet. This approach allows India to leverage ongoing research instead of starting a completely new project.

However, adapting the radar for a stealth fighter introduces unique engineering challenges. The Su-57’s nose cone has a different internal geometry compared with the Su-30MKI. The Virupaksha array, originally designed with a circular diameter of roughly 950 millimeters, would likely need to be reshaped into an elliptical configuration—approximately 900 by 700 millimeters—to fit within the aircraft’s radar aperture.

Despite the smaller frame, GaN technology allows the radar to maintain extremely high detection performance. Defence engineers estimate that the radar could support thousands of transmit-receive modules, potentially offering detection ranges exceeding 400 kilometers against large aerial targets.

More importantly, an Indian radar would enable a universal weapon interface—allowing the stealth fighter to deploy indigenous systems like the Rudram anti-radiation missile series or future long-range air-to-air weapons without waiting for foreign integration approvals.

This philosophy reflects a broader shift in India’s defence procurement strategy. Rather than importing closed systems, the focus is increasingly on modular platforms that allow domestic technology to be inserted and upgraded over time. If implemented successfully, integrating Virupaksha into the Su-57 would represent more than just a radar replacement—it would mark a decisive move toward digital independence in one of the most complex combat aircraft ecosystems in the world.