Depends on what your environment is and how much sensor jamming.Right, but wouldn't Trek tech have more than IR?
Remember in the DS9 episode "The Siege of AR-558".
The Dominion jammed Federation Sensors, The Federation Jammed Dominion Sensors.
Eventually things went back to more "Primitive" ways of scanning & Detecting the enemy.
Binoculars, IR, Telescopes, listening for enemy movement, etc.
All the basics of tracking & surveillance come back into play once your fancy sensors get jammed, scrambled, or deflected.