Use your imagination. The counter-drone doesn't have to output the exact same energy profile as an attack helicopter, just close enough to trigger the anti-helo-drone's activation.
Examples: the counter-drone outputs only a specific frequency (the anti-helo drone isn't running a whole sound analysis, just a narrow range). It outputs that at much lower decibels (the anti-helo-drone just thinks the helo is farther away). It outputs that sound in bursts and directionally (the anti-helo-drone is only listening in a specific place).
Once found, the counter-drone dispatches a kill drone which can match the anti-helo drone's speed.
Sure all of these "hacks" will be countered by future versions of the anti-helo-drones, but that's kinda my whole point.
"Just close enough" is doing a lot of heavy lifting there.
It doesn't matter if the decoy can match frequency if it can't match amplitude because it's trivial to triangulate the position and eliminate anything that's too quiet. Any helicopter that sounds "farther away" than its actual position is obviously a decoy. Measuring the time of flight on reflections eliminates directional speakers.
These aren't even hacks, this is something an Alexa smart home speaker is equipped to do today. Add a rudimentary radar and the decoy now has to have the same radar cross section as a big metal helicopter. Chaff isn't going to work when sensor fusion includes computer vision.
> Once found, the counter-drone dispatches a kill drone which can match the anti-helo drone's speed.
Once it's dispatched, how is it going to target and intercept a small drone with a tiny radar cross section that has thrust vectoring? That's a job for static CIWS/AA, not a cheap counter drone dispatched from a decoy.
My point is that attackers have the technological and cost advantage here, possibly forever. Civilian quadcopters can't easily take down a 150 knot helicopter now but the technology to make 200+ mph military drones is already here, it just hasn't been combined into a weapon yet. No imagination needed, it's practically inevitable.
That's a lot of specific engineering just to protect the helicopter. Or you can just spend that engineering effort and money on replacing the helicopters with more advanced drones.
>the anti-helo drone isn't running a whole sound analysis, just a narrow range
Why? Sure you might be limited to that if you're using an Arduino but with an FPGA or even a cheap "edge AI" NPU you could do a very thorough analysis (even credit card sized image recognition modules with camera are <$50 now). Heck even a seeedstudio respeaker can do live voice identification and isolation, noise cancellation, and 16 direction source location/indication using 4 microphones!
The thing is, maybe it just doesn't make economic sense to protect the (expensive) helo with such more expensive shenanigans, given the volume of oomph it can bring onto the battlefield.
Knights in armor didn't necessarily die out because of their vulnerability to guns; rather, professional pikemen and musketeers started making more economic sense.
Examples: the counter-drone outputs only a specific frequency (the anti-helo drone isn't running a whole sound analysis, just a narrow range). It outputs that at much lower decibels (the anti-helo-drone just thinks the helo is farther away). It outputs that sound in bursts and directionally (the anti-helo-drone is only listening in a specific place).
Once found, the counter-drone dispatches a kill drone which can match the anti-helo drone's speed.
Sure all of these "hacks" will be countered by future versions of the anti-helo-drones, but that's kinda my whole point.