Coastal surveillance

From blind coast to sensor network

Before 26/11, India's coast was effectively unobserved: no radar chain, no fusion centre, and no agency owning the complete picture. The attackers' trawler crossed the Arabian Sea undetected. The post-attack review produced a deliberate architecture: detect everything (radars, AIS, satellites), fuse it in one picture (NC3I and IMAC), and respond in layers (Navy, Coast Guard, Marine Police).

The coastal radar chain, completed in two phases, gives overlapping coverage of the coastline; electro-optical cameras and low-light devices supplement radars at sensitive points. The NC3I network, operational since 2014, links 51 nodes of the Navy and Coast Guard, enabling any node to see the common operating picture. The IMAC fuses this with white-shipping data from the IFC-IOR's international partners, port and customs data, and intelligence inputs.

• 26/11 crossed an unobserved sea; the architecture was the answer.
• Radar chain: 46 + 38 stations covering mainland and islands.
• NC3I: 51 nodes sharing one operating picture.
• IMAC fuses national and international data feeds.

The small-boat problem

Radars and AIS track cooperative, larger vessels; the threat hides in the uncooperative small fleet. India has over 2 lakh fishing boats, most without transponders, operating close to shore where radar discrimination is hardest. A hostile boat looks exactly like a fishing boat until it does not — the 26/11 attackers used a hijacked fishing trawler precisely for this camouflage.

Responses include mandatory registration and colour-coding of fishing boats, biometric ID cards for fishermen, fitting AIS-Class B and satellite-based transponders on progressively smaller vessels, and analytics at IMAC that flag anomalous behaviour — a boat loitering off a port, a trawler on an unusual track, a vessel that goes 'dark' by switching off its transponder. The technical and fiscal challenge of instrumenting the entire small-boat fleet remains the system's frontier.

• 2 lakh+ fishing boats are the surveillance blind spot.
• 26/11 used a hijacked trawler as camouflage.
• AIS-B and satellite transponders are being pushed to smaller vessels.
• Behaviour analytics flag loitering, unusual tracks and 'dark' vessels.

Space, drones and the extended sensor grid

Beyond the coast, space-based assets extend the watch: ISRO's radar-imaging satellites (RISAT series) see through cloud and dark; Oceansat monitors the sea surface; and the Navy's dedicated GSAT-7 (2013) and GSAT-7R communications satellites link the fleet. Maritime Domain Awareness satellites and automatic identification from space (space-based AIS) track shipping across the Indian Ocean.

Unmanned systems are the newest layer: the Navy and Coast Guard operate Sea Guardian (MQ-9B) long-endurance drones from leased and, now, procured fleets, alongside indigenous Tapas and smaller UAVs for coastal patrol. Aerostats and coastal cameras cover specific vulnerabilities like the Gulf of Khambhat and the Palk Strait. The trend is towards a persistent, multi-layer sensor grid where nothing moves unobserved from the deep sea to the beach.

• RISAT radar satellites see through cloud and darkness.
• GSAT-7 is the Navy's dedicated communications satellite.
• MQ-9B Sea Guardian drones provide long-endurance maritime patrol.
• The goal: persistent observation from deep sea to beach.

Data fusion, AI and the human layer

Sensors produce data; security requires sense-making. The IMAC's fusion engines correlate radar tracks, AIS identities, satellite detections, port records and intelligence to build the recognised maritime picture. Artificial intelligence and machine learning are being layered on to detect anomalies at scale — the only way to watch lakhs of daily vessel movements with finite analysts. The IFC-IOR extends this picture to 20+ partner nations, creating a regional commons of maritime information.

The final layer is human: fishermen trained to report suspicious activity, coastal villages with communication links to marine police, and the Sagar Kavach exercises that test the whole chain — detection, identification, interception — and fix what fails. Technology has made India's coast far harder to approach unseen than in 2008; the remaining vulnerabilities are the small-boat fleet, insider threats in ports, and the eternal risk of complacency between crises.

• AI/ML anomaly detection is essential at the scale of lakhs of vessel movements.
• IFC-IOR shares the picture with 20+ partner countries.
• Fishermen and coastal villages are the human sensor layer.
• Sagar Kavach exercises continuously test the detection-to-interception chain.

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