Ships of all sizes depend on GPS for navigation through ports. The daily volume of cargo at many large ports is valued in the hundreds of millions of dollars. Pilots need to know when their GPS based navigation systems have been compromised; otherwise, the results could be catastrophic for both the ship and the port, and result in substantial loss of revenue.
Airports are becoming increasingly reliant on GPS for precision approach as legacy approach systems are decommissioned. Past events have demonstrated the necessity of not only detecting GPS interference, but also providing information to eliminate them. If the GPS signal near the airport is not reliable, pilots need to know immediately that their GPS based approach system is compromised.
Telecommunications equipment uses GPS for precision timing. It has been demonstrated that a cellular site whose time has been altered by 20 microseconds cannot hand-off calls. Additionally, Synchronous Optical Networks (SONET), which provide the backbone for most all telecommunications, relies heavily on GPS for synchronization.
Electronically traded transactions are often based on GPS derived time. Delaying the time by even milliseconds can result in transactions being made with out-of-date prices and result in substantial loss of revenue. Without a proper detection system, a short-term spoofing attack on a stock exchange might go unnoticed.
Synchronization of the power grid increasingly relies on precise timing derived from GPS. Spoofing attacks on power grid timing receivers can cause instability in the grid. To keep the grid on time, timing receivers need to know when GPS is compromised so they can switch to alternate time references.