> Why does it matter whether you are over another superpower's land?
One of the fairly easy ways to defeat stealth is by operating your radar at a low frequency. As the wavelength becomes "much longer" than any characteristic dimension of the airplane, the shape of the airplane matters less and less and the wave will penetrate deeper and deeper layers of radar absorption material.
But there's no such thing as a free lunch.
The problem is that the resolution of your radar depends on the physical size of your antenna relative to the wavelength (either the diameter of the dish, or the spacing of the antenna elements in a multi-static or phased array). So low frequency = long wavelength = bad resolution. You know a plane is in your airspace, but not where in your airspace.
You can solve the resolution problem by installing a physically large antenna. The size of the antenna should be several times longer than the wavelength. That might mean having a single very large dish or it might mean coherent transmitters located hundreds or thousands of meters apart. Great, now we have defeated stealth and have high resolution.
But remember how we were talking about wavelengths much longer than the airplane? How do you carry an antenna that is several times longer than the wavelength for a wavelength that is several times longer than your airplane? I can think of one way: trail wires behind you--but that turns you into a flying bullseye. You might as well file a flight plan.
That creates an asymmetry: It's much easier for the side on the ground to get a good picture of what is going on in the air.
One of the fairly easy ways to defeat stealth is by operating your radar at a low frequency. As the wavelength becomes "much longer" than any characteristic dimension of the airplane, the shape of the airplane matters less and less and the wave will penetrate deeper and deeper layers of radar absorption material.
But there's no such thing as a free lunch.
The problem is that the resolution of your radar depends on the physical size of your antenna relative to the wavelength (either the diameter of the dish, or the spacing of the antenna elements in a multi-static or phased array). So low frequency = long wavelength = bad resolution. You know a plane is in your airspace, but not where in your airspace.
You can solve the resolution problem by installing a physically large antenna. The size of the antenna should be several times longer than the wavelength. That might mean having a single very large dish or it might mean coherent transmitters located hundreds or thousands of meters apart. Great, now we have defeated stealth and have high resolution.
But remember how we were talking about wavelengths much longer than the airplane? How do you carry an antenna that is several times longer than the wavelength for a wavelength that is several times longer than your airplane? I can think of one way: trail wires behind you--but that turns you into a flying bullseye. You might as well file a flight plan.
That creates an asymmetry: It's much easier for the side on the ground to get a good picture of what is going on in the air.