La nuova tecnologia anti-drone ucraina utilizza il targeting acustico per dare la caccia silenziosamente agli Shahed

I suggested for electric ground drones and other vehicles, using microphone arrays maybe 2 years back. 

The technology is there in everyday products like your amazon echo.  I would guess a moving dish microphone could augment its direction finding ability but you can do it with static arrays. 

Further to this I suggest that air defebses using powered – glide phases may allow drones to ascend above or similar altitude to the target object and during unpowered glide phases then vector to the enemy target from onboard microphones.

The ability for a drone to hear the target would be effected by high air speed and active propulsion, but this could significantly be removed by noise cancellation using microphones poaitioned to isolate chassis and local self generated noises. So quiet electric propulsion may work. 

Having programmed periods of powered propulsion and glide on a schedule also can avoid the problem of confusing ground detectors, especially if the interceptor was using a loud propulsion method. 

The Germans already have a microphone equiped drone which can isolate artillery gun position within a few degrees from significant range, and it does this whilst flying (as I understand).