Prithvi Air Defence (PAD) air defence system is reported to use QMF seeker for target acquisition

DRDO has initiated the development of the Quadrature Monopulse Frequency (QMF) seeker. The seeker is part of India’s drive for advanced radar-guided targeting in next-generation missiles and autonomous platforms.​

This advanced radar processing technique allows the seeker to accurately determine the angular position of a target, improving a missile's guidance, range, and resistance to countermeasures. 

Quadrature Monopulse is a refined radar signal processing method that measures the angular position of a moving or evasive target with high precision. It operates by generating sum and difference signals, permitting robust directional discrimination even in noisy or cluttered environments. This technique enhances guidance accuracy for both semi-active and fully autonomous seekers.​

A QMF seeker typically utilises dual-channel (in-phase and quadrature) detection and processing, which excels at separating direct from multipath or reflected signals. This results in improved target lock and resilience to electronic countermeasures and signal jamming. The architecture also allows Doppler processing and multi-target discrimination within complex engagement scenarios.​

Quadrature Monopulse techniques drastically boost terminal guidance reliability, especially for high-velocity and manoeuvring targets. The integration of QMF seekers supports modern missile requirements for challenging environments with advanced active countermeasures and low-observable threats.​

DRDO’s focus on QMF technology is consistent with broader efforts to indigenise sophisticated missile seeker technologies, minimising import dependencies and strengthening national security. Such seekers are applicable across air-to-air, surface-to-air, and guided munitions platforms.​

The QMF seeker is poised to become integral to next-generation Indian missiles and anti-drone systems, supporting both stand-alone and multi-mode navigation architectures. This initiative is likely to spawn wider research collaborations and technology transfers within India’s defence sector.​

IDN (With Agency Inputs)