IFF System Concept Based on Time Synchronization

Identification of friend or foe (IFF) in the tactical theater is a complex technical and operational problem with extremely important implications to the nation's success in waging war. A practical, inexpensive IFF system which can reliably identify friends in a hostile ECM environment is desperately needed by the United States and NATO. This paper presents an IFF system concept which utilizes existing technologies and devices to create a new tactical IFF system that addresses the following electronic counter-counter-measure (ECCM) problems: 1) vulnerability to enemy antiradiation missiles, 2) vulnerability to jamming, 3) vulnerability to enemy spoofing and deception, and 4) vulnerability to enemy exploitation ("eavesdropping"). The system concept is based on accurate time-synchronization among all participants and represents a radical departure from current IFF methods. However, it does retain the basic interrogateresponse approach. It utilizes spread-spectrum, low-data-rate signaling which offers substantial resistance to enemy jamming and makes spoofing and deception extremely difficult. The spreadspectrum techniques include: frequency hopping, time jitter, and intrapulse Coding. This combination of techniques is used to maximize the antijam and convert capabilities of the system without putting undue burden on a single technology.