• Rednax@lemmy.world
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      11 months ago

      Do note that the this claim comes from the same people who don’t hand out any actual specs and always fly with an additional reflector. The latter makes it easy for radars to see them again. This is helpful in allied airspace, but it also makes it impossible to verify the claim.

      Also note that modern radars are sensitive to how fast an object approaches (or leaves) the radar. Bumblebees don’t break the soundbarrier usually, so it is possible to see these planes, but you do have to tweak your radar for it. (Hence why the US doesn’t give specs.)

        • Rednax@lemmy.world
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          11 months ago

          Correct. But integrating over multiple pulses, and using the latest Tx and Rx modules, sensitivity is not the problem anymore. Radars can easily see every damn bumblebee in a 100km radius. The problem is filtering data, so that processing and/or the user is not overloaded. For example, if you track every single bird with a radar that has a 100km radius, you will not be able to see anything on the operator screen other than birds.

          Doppler is easy to filter on early in the processing stage. Meaning that if you can detect the aircraft, you can still separate it from all other bumblee like objects. Clutter tends not to move that fast.

      • BastingChemina@slrpnk.net
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        11 months ago

        So they just need to build an aircraft that moves at the same speed and height as a bumblebee. Bam ! Undetectable killing machine.

      • Socsa@sh.itjust.works
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        11 months ago

        You’d be surprised the velocity you get from the return on a bird’s flapping wing. Also the Doppler ambiguity smears with SNR, so you’ll see a bird as something moving between 30 and 300mph at the edge of sensitivity.

      • Rednax@lemmy.world
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        11 months ago

        Radar is echolocation with EM waves (low frequency light) instead of sound waves. And there are already plenty of radar guided missiles.

          • Rednax@lemmy.world
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            11 months ago

            That is called passive sonar. I suspect that it is kinda hard to hear from the missile. Anything behind you is certainly not hearable, since the missile goes faster than sound. I have no idea if you could measure the sound coming from the front. You also have to take into account that you are chasing an after image, since the plane is also faster than sound. But torpedoes use this, so the idea is valid.