The Indian Navy, in collaboration with the Defence Research and Development Organisation (DRDO) and private sector partners, is advancing a major initiative to deploy a network of advanced underwater sensors across the Indian Ocean Region (IOR). This strategic move is a direct response to the increasing presence and activities of Chinese submarines and research vessels in the region, which pose significant security challenges for India’s maritime interests.

The planned sensor network will focus on key maritime zones, including the Ninety East Ridge, the Andaman and Nicobar Islands, and the Bay of Bengal. These areas are strategically vital due to their proximity to crucial sea lanes and choke-points such as the Malacca and Sunda Straits.

The Ninety East Ridge, in particular, is a linear underwater feature ideal for submarine navigation and has recently attracted attention following a month-long survey by China’s research vessel Dong Fang Hong 3, raising suspicions about efforts to map the seabed for submarine operations.

The underwater sensor systems under development are expected to incorporate a range of cutting-edge technologies. These include passive and active sonar arrays, magnetic anomaly detectors (MAD), and superconducting quantum interference devices (SQUIDs).

Passive sonar will enable stealthy, non-intrusive surveillance by capturing noise emitted by submarines, while active sonar systems will provide precise detection and ranging capabilities in high-threat situations. The integration of MAD and SQUID technologies will further enhance the detection of submerged metallic objects, such as submarines, by sensing minute magnetic field disturbances.

This initiative draws inspiration from the “Fish Hook Undersea Defence Line” established by the United States and Japan in the Pacific, which employs seabed-based hydroacoustic sensors to monitor submarine movements from Japan to Southeast Asia. India aims to deploy similar systems at the northern and southern tips of the Andaman and Nicobar Islands, effectively creating an early warning barrier against Chinese submarine incursions into the IOR.

The urgency of this project is underscored by the growing numerical and technological edge of the People’s Liberation Army Navy (PLAN), which operates a fleet of over 60 submarines, including advanced nuclear-powered ballistic missile submarines. Complicating the security environment further is Pakistan’s acquisition of eight Yuan-class submarines with air-independent propulsion (AIP) systems from China, presenting India with a two-front underwater threat.

India’s own submarine fleet, consisting of 13 conventional diesel-electric submarines, is currently outmatched both in numbers and technology. Delays in the Project 75I program, intended to build six AIP-equipped submarines, have heightened the need for alternative measures to bolster anti-submarine warfare (ASW) capabilities.

The development and deployment of indigenous underwater sensors are thus seen as a critical step in enhancing India’s underwater domain awareness (UDA) and maintaining strategic pre-eminence in the IOR. The Naval Physical and Oceanographic Laboratory (NPOL) in Kochi, with its expertise in sonar systems such as the Abhay and HUMSA-UG, is expected to play a central role in this effort. DRDO’s Submersible Platform for Acoustic Characterisation & Evaluation (SPACE) facility and the Ocean Data Centre will support testing, calibration, and optimization of these sensor systems before their operational deployment.

There are also indications of potential collaboration with Japan and the United States, with discussions around integrating India’s sensor network with the existing US-Japan “Fish Hook” SOSUS (Sound Surveillance System) network, further strengthening the collective monitoring of Chinese submarine activity in the broader Indo-Pacific.

India’s deployment of an advanced underwater sensor network marks a significant escalation in its efforts to counter growing Chinese and Pakistani submarine threats in the Indian Ocean. By leveraging indigenous technology and international partnerships, the Indian Navy aims to secure critical maritime zones, ensure early warning of hostile submarine activity, and reinforce its strategic position in the region.

Agencies