GPS Spoofing and Autonomous Boats: The Strait of Hormuz Is Now a Navigation War Zone
Picture a 300-meter supertanker, fully loaded, approaching one of the world's most critical shipping chokepoints. The crew checks their instruments and sees that they are at Dubai International Airport. They are not at Dubai International Airport. They are somewhere in the Strait of Hormuz, and the navigation system is lying to them.
That is not a malfunction. That is Iran's method of threatening the shipping lanes without firing a single shot.
Todd Humphreys, an aerospace engineering professor at the University of Texas at Austin, has studied GPS spoofing for years. He says the evidence points squarely at Iran. Scientific American reported that in a 24-hour period, more than 1,100 vessels experienced GPS or AIS disruption in the Gulf, according to an analysis by Windward, a maritime data firm. The spoofing was not random noise. Ships were shown positions at airports, inside nuclear power plants, over Iranian dry land. On a normal day, 130 to 150 vessels transit the strait, which is just 21 miles wide at its narrowest point. In that same 24-hour disruption window, fewer than 100 ships made the crossing, Windward's analysis found.
The US Navy's answer to this is a 16-foot autonomous boat called GARC — the Global Autonomous Reconnaissance Craft. Built by Maryland company BlackSea, the vessel is roughly 5 meters long with a 200-horsepower engine and a 1,000-pound payload capacity. According to Army Recognition, its operational range stretches to 700 nautical miles at cruise speed, or 1,600 nautical miles if it drops to 5 knots. GARC uses a system called MAPC2 for mission planning, autonomous navigation, and remote control. Reuters confirmed that in Operation Epic Fury, the craft has logged more than 450 underway hours and 2,200 nautical miles of patrols in the strait. The Pentagon confirmed the deployment in late March 2026. It is the first time the United States has publicly acknowledged using uncrewed drone boats in an active conflict.
GPS and AIS — the Automatic Identification System that vessels broadcast to avoid collisions — were never designed as combat systems. Iran has made them into exactly that. The strait carries roughly a fifth of the world's oil, and when the navigation systems cannot be trusted, shipowners have three options: transit blind, pay war-risk insurance premiums that have climbed to between 3.5 and 7.5 percent of a vessel's value, according to Lloyd's List Intelligence, or avoid the crossing entirely. Approximately 1,000 vessels and their crews remain trapped in the Gulf because captains will not take the risk, Lloyd's List Intelligence reported. Chubb is the lead partner on a $20 billion US International Development Finance Corporation maritime reinsurance plan designed to keep ships moving through the region. The commercial maritime industry is paying for the surveillance infrastructure it now needs to operate in a war zone.
Windward identified at least 21 new AIS jamming clusters across the UAE, Qatar, Oman, and Iranian waters in its recent analysis. The spoofing is not stopping.
Iran has turned navigation infrastructure into a weapon. The US Navy's GARC deployment is the tactical response. The structural shift is that commercial shipping now requires real-time position verification, alternative navigation methods, and active monitoring to distinguish genuine AIS broadcasts from fabricated ones. This is not a temporary disruption to be managed. It is a permanent change to the operational environment of global maritime commerce.
The sailor at the instrument panel, watching the false position resolve over land that does not exist, is not a glitch in the system. He is the target.