What kind of significance does infrared sight have in national defense

Infrared sights works at infrared bands, whose characteristics of imaging have a obvious advantage over white light sights, having a significant meaning in the modern battlefield.

Firstly, all the objects emit infrared radiation, which infrared sights can transmit into electrical signal, then process and form digital image displayed on the eyepiece, enabling it to operate around the clock; 

Secondly, infrared wavelength is longer than visible light wavelength, and infrared has a much stronger ability to penetrate fog than visible light, so as to effectively identify the target through the smoke on the battlefield;

Last, the imaging displayed by infrared sights is the temperature difference between target and environment, which is not affected by the disguise of visible light, enabling it to identify the target better.