On a sultry summer night in July 2019, the MV Manukai was arriving at the port of Shanghai, near the mouth of the Huangpu River. This busy tributary of the Yangtze winds through the city and includes the Bund, a historic waterfront area and tourist hot spot. Shanghai would be the American container ship's last stop in China before making its long homeward journey to Long Beach, California.
As the crew carefully maneuvered the 700-foot ship through the world's busiest port, its captain watched his navigation screens closely. By international law, all but the smallest commercial ships have to install automatic identification system (AIS) transponders. Every few seconds, these devices broadcast their identity, position, course, and speed and display AIS data from other ships in the area, helping to keep crowded waterways safe. The position data for those transponders comes from GPS satellites.
According to the Manukai's screens, another ship was steaming up the same channel at about seven knots (eight miles per hour). Suddenly, the other ship disappeared from the AIS display. A few minutes later, the screen showed the other ship back at the dock. Then it was in the channel and moving again, then back at the dock, then gone once more.
Eventually, mystified, the captain picked up his binoculars and scanned the dockside. The other ship had been stationary at the dock the entire time.
When it came time for the Manukai to head for its own berth, the bridge began echoing to multiple alarms. Both of the ship's GPS units—it carried two for redundancy—had lost their signals, and its AIS transponder had failed. Even a last-ditch emergency distress system that also relied on GPS could not get a fix.
Now, new research and previously unseen data show that the Manukai, and thousands of other vessels in Shanghai over the last year, are falling victim to a mysterious new weapon that is able to spoof GPS systems in a way never seen before.
Nobody knows who is behind this spoofing, or what its ultimate purpose might be. These ships could be unwilling test subjects for a sophisticated electronic warfare system, or collateral damage in a conflict between environmental criminals and the Chinese state that has already claimed dozens of ships and lives. But one thing is for certain: there is an invisible electronic war over the future of navigation in Shanghai, and GPS is losing.
The mystery deepens
Although the Manukai eventually docked safely, its captain was concerned enough to file a report later that day with the US Coast Guard's Navigation Center, which collects worldwide.
"All [antenna] connections are secured and dry," he wrote. "There have been no other issues with these units. [I] suspect GPS signal jamming is occurring at this berth."
In fact, something far more dangerous was happening, and the Manukai's captain was unaware of it. Although the American ship's GPS signals initially seemed to have just been jammed, both it and its neighbor had also been spoofed—their true position and speed replaced by false coordinates broadcast from the ground. This is serious, as are linked to navigational mistakes that cause collisions or groundings.
When mariners simply lose a GPS signal, they can fall back on paper charts, radar, and visual navigation. But if a ship's GPS signal is spoofed, its captain—and any nearby vessels tracking it via AIS— will be told that the ship is somewhere else entirely. Nor did the attacks stop once the Manukai was safely at its dock. Several times that day, its AIS system reported that it was over three miles distant.
Half a world away from Shanghai, a tip landed on the Washington, DC, desk of a researcher at the Center for Advanced Defense Studies (C4ADS), a nonprofit that analyzes global conflict and security issues. The new tip, from a shipping industry source, suggested that somebody was spoofing GPS signals in Shanghai.
