[RoughDobermann]

heat-seeking, not infrared

Huh?

[Sabretooth]

Heat seeking is more of a thermal sensing tech. Infra-red is just a color of light not visible to the naked eye.

[jimbo123]

The SA-18 GROUSE (Igla 9K38) is an improved variant in the the SA-7 & SA-14 series of manportable SAMs. As with the earlier SA-14, the SA-18 uses of a similar thermal battery/gas bottle, and the SA-18 has the same 2 kilogram high-explosive warhead fitted with a contact and grazing fuse. But the missile of entirely new design with substantially improved range and speed,. The new seeker and aerodynamic improvements extend its effective range, and its higher speed enables it to be used against faster targets. The SA-18 has a maximum range of 5200 meters and a maximum altitude of 3500 meters. The 9M39 missile SA-18 employs an IR guidance system using proportional convergence logic. The new seeker offers better protection against electro-optical jammers; the probability of kill against an unprotected fighter is estimated at 30-48%, and the use of IRCM jammers only degrades this to 24-30%.

The Igla-M [SA-N-10 ] is the naval version of the SA-18.

[eno_]

It's possible it could look for characteristic spectra of fuel combustion, instead of just whatever is brightest in the IR range. But I think it is more likely that's an error.

[eno_]

From #50: "The seeker is sensitive enough to home in on airframe radiation, and the two-color sensitivity is designed to minimize vulnerability to flares."