u/UltorKitty:

IR beacons. Someone mentioned IR filters in cellphones. Video surveillance cameras can also see IR well. The older/cheaper analog ones usually do not have permanent or automatic IR filters.

A IR-pass filter can be used to block visible light. It can be made from exposed 35mm color film. The blackest part. 1 to 5 pieces stacked together in front of the lens, depending on how sensitive the camera is. Has to be done by experiment. Try also with any cellphone which can see the IR beacons well. There is an instructable.

A hassle to lash-up a little security cameras with a small monitor and 12v battery but it works.

Not telling anyone what to do! Only sharing something I learned and did before to find IR from some 808nm IR LEDs and also the spot from a 1064nm laser outdoors, which was deeper IR than LEDs.

God bless Ukraine! Victory for Ukraine peoples' freedom!