• Rednax@lemmy.world
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    9 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.

    • jimbolauski@lemm.ee
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      9 months ago

      Doppler processing eliminates clutter it doesn’t eliminate EMI, thermal noise, or atmospheric issues.

      China’s 366 radar can detect 0.1 sq meter targets at 20km. It’s China’s most modern radar and it’s not close to 100km detection range for LO aircraft.

      Play around with the radar range equation.
      For a 100km detection range. 1 MW of output power, 30 dB antenna gain, 1Ghz Tx frequency, radar cross sectional area 0.1 m sq, minimum detection signal 0.005 nano watts.

      On low power systems where you can have much lower internal emi, -100 dB (0.1 nano watts) is as low as you can get outdoors.