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.)
You are talking about Doppler processing. Basically you can filter out all the things that are not moving fast based on how much the frequency is compressed and lower your noise floor. You will still have other noise sources but minimizing clutter will help, if the return is below other noise sources you still will not be able to detect it.
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.
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.
You are talking about Doppler processing. Basically you can filter out all the things that are not moving fast based on how much the frequency is compressed and lower your noise floor. You will still have other noise sources but minimizing clutter will help, if the return is below other noise sources you still will not be able to detect it.
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.
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.