Navy tracks foreign vessels in sovereign waters with covert sensors
By Marcus Boone ·
Foreign ships were watched entering and exiting ports as the Navy unobtrusively placed portable sensor nets in the shallow waters of potential adversaries to track stealthy submarines.
In September 1994, the U.S. Navy ran an exercise called "Operation Ghost." Along with the "September Research Operation," these tests were designed to prove that the military could do more than just listen to the deep ocean. They wanted to see if they could track diesel-electric submarines—the quieter, stealthier variety—and spot mine-laying operations in the shallow, noisy chaos of the coast.
The record, hosted by the FAS Intelligence Resource Program, describes the Advanced Deployable System (ADS). For decades, the public knew about "Project Caesar" or the later Integrated Undersea Surveillance System (IUSS)—the massive, fixed arrays of SOSUS that acted as a tripwire for Soviet subs in the open Atlantic. But by 1992, the strategic appetite shifted. The Cold War had ended, and the Navy began focusing on the "littorals"—the coastal fringes where regional conflicts actually happen.
Operation Ghost
The ADS was conceived not as a permanent fixture of the seabed, but as a "theater-deliverable" asset. It was meant to be "rapid and covertly deployable." While the old SOSUS arrays were the equivalent of a permanent fence, the ADS was a portable net. The 1994 tests focused on detection and tracking performance against diesel-electric submarines, which are notoriously difficult to hear when running on battery power.
The FAS mirror notes that the importance of this portable capability would "intensify" as the Navy shifted its focus toward these shallow waters and as U.S. forces were downsized. The government did not rely solely on internal labs to solve the problem of littoral anti-submarine warfare. Instead, they opened the floor to industry. By early 1994, concept studies were being churned out by AT&T, Lockheed, IBM, and McDonnell-Douglas.
By June 3, 1994, the Commander, Space and Naval Warfare Systems Command released a Request for Proposal for the Demonstration and Validation Phase. The goal was clear: take the theory of the concept studies and turn it into a prototype that could survive the noise of a coastline.
Shallow Water
Tracking a submarine in the deep ocean is a matter of patience and distance. Tracking one in a harbor or on a coastal shelf is a matter of precision. The ADS was designed to operate in "the most difficult shallow water environments" with "very high target position accuracy." This wasn't just about national defense in the abstract; the record explicitly links the system to "Regional Conflicts."
The system's reach extended to ships "exiting or entering port." This effectively turns the ocean's edge into a monitored checkpoint, allowing the Navy to maintain a persistent acoustic gaze on foreign vessels before they even hit the open sea. The technology was not a sudden invention but an accumulation of surveillance capabilities, drawing from the Fixed Distributed System (FDS), the Advanced Deployable Array (AdDA), and the Port Area Surveillance (PAS) program.
This evolution highlights a shift in how the state views the sea. Under the IUSS, the ocean was a barrier to be monitored from the edges. Under the ADS, the ocean—specifically the shallow, sovereign waters of other nations—became a space where the U.S. could "unobtrusively" deploy fields of sensors. The system was intended to be placed "prior to or during regional conflicts," essentially pre-positioning the ears of the Navy in the littoral zones of potential adversaries.
Loral Federal Systems
The money and the contracts followed the capability. On April 10, 1995, the Space and Naval Warfare Systems Command announced the award of the Demonstration and Validation Phase contract to Loral Federal Systems, a company that would later merge into Lockheed-Martin Federal Systems.
At the same time, the Naval Research Laboratory was pushing into the "All Optical Deployable System," awarding a contract to Litton on June 30, 1995. The objective was a two-node test in the San Diego area by the spring of 1996. This optical approach suggests a move toward higher bandwidth and more precise sensing than traditional acoustics, aiming to eliminate the noise that often masks submarines in shallow water.
Then there was BBN, a firm that teamed with Loral to handle the "engineering and development services." BBN's role was to define the "overall operational concept" and provide the software and training necessary to turn raw acoustic data into actionable intelligence. This intelligence was fed into the Surveillance Direction System (SDS), which reported submarine and undersea activity directly to Joint Task Force Commanders (JTFC) and tactical assets.
As the system matured, the government checked the boxes on the environmental impact. On November 4, 1998, the Navy issued a "Finding of No Significant Impact" for the Advanced Deployable System's environmental assessment. The record leaves the actual operational status of these "unobtrusive" fields of sensors in the late nineties a gap, but it confirms the intent: a covert, rapid-response ear placed in the waters of any regional contingency area the Navy deemed necessary.