EW 101 Infrared Systems and Countermeasures – Part 9 IR Jammers By Dave Adamy P The Journal of Electronic Defense | August 2013 48 latforms that must dwell within the lethal range of IR guided threats would require an extremely large number of flares to provide adequate protection. JAMM Therefore, the use of IR jammers is the ING SIG NAL best solution. As shown in Figure 1, an IR missile tracks on the IR energy from some part of the targeted aircraft. The jammer on MISSILE TRACKER the target aircraft directs modulated IR energy at the attacking missile. Figure 1: The IR jammer directs IR energy into the missile tracker with a waveform that causes the missile to fail to recognize a valid target or guide away from the target. The January, February and July 2013 “EW 101” columns show how received IR energy is processed to determine the direction in which The IR jammer creates a modulated IR emission, which is the missile must be steered to home on the target. Figure transmitted toward the attacking missile, and inputs modu2 shows the missile tracker components. IR energy passes lated energy to the sensing cell. This energy causes the procesthrough a lens and a reticle to a sensing cell which generates sor to output improper tracking information – either breaking a video signal from which a processor generates missile guidthe lock on the target or steering the missile away from its ance commands. intended target. LENS RETICLE FROM TARGET IR ENERGY SENSING CELL VIDEO SIGNALS PROCESSOR GUIDANCE COMMANDS Figure 2: The tracker in the missile passes IR energy from the target through a reticle to a sensing cell which generates signals to its processor from which guidance commands are generated.http://www.naylornetwork.com/jed-nxt/index.asp