The Indian Navy has issued a Request for Proposal for an Indigenous Harbour Defence System, or IHDS, to replace its legacy Integrated Underwater Harbour Defence and Surveillance System at Mumbai, Karwar, Kochi and Visakhapatnam.

The proposed system is intended to create an integrated, indigenous surveillance and command-and-control network around four of India’s most important naval hubs, strengthening protection against surface, subsurface and asymmetric threats.

The IHDS will combine coastal surveillance radars, electro-optical and infrared suites, diver-detection sonars, unmanned aerial vehicles and a centralised command-and-control architecture.

Its command-and-control system is required to handle more than 600 surface tracks and over 50 subsurface tracks simultaneously. This capacity will enable operators to maintain a consolidated operational picture across a busy harbour environment containing naval vessels, merchant shipping, fishing craft and other contacts.

The requirement reflects the need to distinguish legitimate activity from potentially hostile or suspicious movement in real time, while allowing naval security teams to assess and respond to threats rapidly.

The sonar network must provide 360-degree underwater surveillance around protected naval installations and harbour approaches.

It must detect divers at ranges of 500–700 metres, swimmer delivery vehicles at 1 km and midget submarines at up to 1.5 km. These capabilities are aimed at countering covert underwater intrusions against warships, jetties, submarines, fuel facilities and other critical naval infrastructure.

The sonar requirement is particularly significant because divers, underwater vehicles and small submarines can exploit the cluttered acoustic environment of ports and shallow coastal waters to approach high-value assets undetected.

The Navy plans to deploy 13 sonar systems under the IHDS programme, forming the underwater detection layer at the four selected locations.

The surface-surveillance element will include five X-band radars with a detection range of at least 150 km. These radars will be required to monitor vessel movement beyond immediate harbour limits and provide early warning of approaching contacts.

X-band radar is suited to detecting and tracking smaller surface craft, including fast boats, in coastal and harbour environments. Its inclusion indicates that the IHDS will cover both close-in security and wider maritime approaches.

Five electro-optical and infrared surveillance suites will complement radar and sonar coverage. The suites are expected to use medium-wave infrared, short-wave infrared and day cameras to provide round-the-clock visual identification.

The electro-optical systems must be able to detect boats at ranges of up to 20 km. The multi-spectral arrangement will support target identification in daylight, darkness, haze and other challenging coastal-weather conditions.

The proposed system will also include vertical take-off and landing unmanned aerial vehicles, providing an airborne surveillance component for harbour-security operations.

The VTOL UAVs are required to operate at ranges of 20–25 km and remain airborne for at least two hours. They could be used to investigate radar contacts, monitor harbour approaches, support patrol craft and provide visual confirmation of suspicious activity.

The indigenous IHDS is expected to replace the older IUHDSS architecture, which integrated radars, electro-optical cameras and sonars to establish real-time awareness around naval harbours. The existing system was designed to detect, locate and track threats including small boats, submersibles, swimmer delivery vehicles, divers and swimmers.

The Navy inaugurated an IUHDSS at Mumbai in 2017, describing it as a major step in strengthening harbour defence and security against asymmetric threats. Its sensors were positioned to provide comprehensive surveillance and analysis of activity in Mumbai Harbour.

A similar system was commissioned at Port Blair in February 2024, where the Navy said it could detect, identify and track surface and underwater targets near the naval jetty, underlining the continuing importance of layered harbour protection at strategically significant naval facilities.

By seeking an indigenous successor system, the Navy is placing emphasis on domestic integration of sensors, data links, command software, unmanned systems and support infrastructure. The programme could offer Indian industry an opportunity to develop a scalable harbour-security solution for future naval bases and other sensitive maritime facilities.

Agencies