Planners also can locate a single platform amid a host of emitters for precision attack. The overall SEI benefit is greatly increased situational awareness, according to Dr. Preston Grounds, manager, electronic combat technology program. A fleet, for example, that suddenly records a series of radar signals from ships passing nearby in a dense fog can identify these vessels if it has their signal fingerprints in its database. Similarly, an unusual radar emission from a rapidly approaching vessel or aircraft may resolve into a pair of emitters that betrays the presence of multiple platforms. Signal processing is the key enabling technology for this system.
Faster computers translate to faster processing, which permits identifying more signal features.
An omnidirectional antenna alerts the system to a radar emitter. A directional antenna with a narrower beamwidth homes in on the emitter and extracts the signal from noise. The only way for an adversary to spoof the identification process is to perform extensive repair or replacement on the emitter, Grounds says. Normal repairs or maintenance, as well as modest modifications, will not alter the fingerprint sufficiently to fool the identification system. These emitter fingerprints encompass repeatable characteristics, the amount of which varies with each type of emitter and existing signal noise.