actually, we DO have the sensor thing. it uses heat, not infra
red. the police n SAF people are using it now... costs a bomb
though
It cannot penetrate the thick vegetation !!! You have to
approach it to a certain distance which is close , before it
can detect, on the so call screen you see most properly the
face or hands or legs area - provide those are not cover by
vegetation.
At the moment - there is nothing heat, infra or thermal - that
can penetrate thick vegetation .... !!!
If he is out there in the jungle - the last thing you find him
wondering into one of these sensor !!! He would stay put deep
inside - why ... moving through the jungle is dangerous at night
especially alone .... it is slow, hard to nagivate, also very high
risk of injury which he does not want at this moment.
The best way to detect him in jungle - using what commerically
call the trail camera ( of course military have much better
version) - which has been use common in US for their hunters and
animals researchers ..... sticking each on to possible trails ....
it have sensors that trigger camera - that will record what have
went past .... It have been use very successfully - they even have
infra red flash - which mean - human or animals will not see the
flash at all , thus does not even know their photo been taken.
Below is an example of one with infra red flash
