The U.S. Navy is carrying out the biggest overhaul of its top-secret undersea surveillance network since the 1950s as China’s naval power surges and new technologies are fast reshaping maritime warfare. Beijing has similar plans of its own.

On a windswept island 50 miles north of Seattle sits a U.S. Navy monitoring station. For years, it was kept busy tracking whale movements and measuring rising sea temperatures. Last October, the Navy gave the unit a new name that better reflects its current mission: Theater Undersea Surveillance Command.

The renaming of the spy station at the Whidbey Island facility is a nod to a much larger U.S. military project, according to three people with direct knowledge of the plans: conducting the biggest reconstruction of America’s anti-submarine spy program since the end of the Cold War.

The revival of the multibillion-dollar effort, known as the Integrated Undersea Surveillance System (IUSS), comes as China has ramped up military exercises around Taiwan, heightening concerns about a potential conflict over the democratically ruled territory, which Beijing wants brought under its control.