Radar Cross Section Estimates
Posted: 2024-Jan-04, 11:38
Out of the ashes of community.combatsim.com
http://simforums.krishty.com/
Haven’t read all articles on the site yet, butmikew wrote: ↑2024-Jan-05, 16:13I've always been a bit sceptical about the effort put into stealth aircraft after hearing some anecdotes about the F-117 not being particularly difficult to track over 30 years ago with 1980s era radars.
Since then, I would assume that developments in Radar signal processing technology would have outpaced aircraft design by a large margin. While a plane may only have the RCS of a bee, the radar just need to track the bees moving over 500mph.
The argument is, there’s already enough bees to track, and if jamming adds 200 more supersonic bees to the echo (which requires just as much energy as emitting two fake non-stealth planes) then everything is back where it started.It is a common misconception that stealth technology is short live and as radar get more powerful, soon, they will be able to out range weapon engagement envelop , thus renders all money spend on RCS reduction a waste. This impression is inaccurate because any technology that can increase a radar peak power or gain will also benefit a jammers in the same ways. And stealth has a synergy relationship with jamming .
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Which mean when RCS is reduced to 1/100th the original value, the required jamming power is also reduced to 1/100th the original value
even if adversary radar can see through jamming of conventional assets from 400 km aways, a stealth asset can still get within 40 km of such radar using exactly same jamming system
I haven’t finished the articles, but I don’t think that’s how radar works.
Right, and Wikipedia has this awesome animation for it:mikew wrote: ↑2024-Jan-06, 10:36These days, instead of a parabolic dish, you have a planar array of individual Transmit/Receive elements. By controlling the phase and amplitude of the RF transmitted /received at each element, you can create multiple transmit and receive beams which can be rapidly 'swept' across an area of space.
I.e. you still need an aircraft’s wingspan for a somewhat-accurate direction measurement (can be done with ground-based mobile radars) but you also need irregular receiver placement to support different wavelengths and polarizations, etc.Interferometers are used when high accuracy DF measurement is important and it is possible to achieve high accuracy of the order (on the order of 0.1 to 1º).Interferometer DF accuracy is determined by the widest baseline pair. Typical cavity-backed spirals, track to 6 electrical degrees, and associated receivers track to 9º, resulting in an rms total of 11º. At a typical 16 dB signal to noise ratio, therms phase noise is approximately 9 electrical degrees. For these errors and an emitter angle of 45º, a spacing of 25 wavelength is required for 0.1º rms accuracy while a spacing of 2.5 wavelength is needed for 1º accuracy. For high accuracy, interferometer spacings of many feet are required. In airborne applications, this usually involves mounting interferometer antennas in the aircraft’s wingtips.