Since there's no current SQF function to return any sort of thermal information from the game itself, I suggest the following command: getThermalBrightness

Syntax1:
getThermalBrightness [positionx, positiony];

returns scalar (0-1) how hot to Thermals the terrain would appear at this point.

Syntax2:
_object getThermalBrightness [modelx, modely, modelz];

returns scalar (0-1) how hot to Thermals the object would appear at this point.
if the point is not on the model, return nil.

It would help with any sort of actual thermal tracking (javelin, sidewinders, etc.), as well as contrasting a thermal object from its background (thermal gradients).