
michaelemouse wrote:hornetfinn wrote:Very true. Besides if I read this correctly, then there are rather narrow spikes even in lower than UHF frequencies. This would mean those radars would likely only see fairly infrequent detections (radar plots) and maybe rather sporadic tracks. This is because low frequency radars usually need quite a few plots to generate track as otherwise they'd have a lot of false target tracks. AESA technology will help somewhat, but the effect is still there.
Not to claim that low frequencies are useless or not a threat (especially for a manned cruise missile like F-117). However low frequency radars are hardly the silver bullet some people claim or wish for.
Is the relationship between the frequency and the number of plots required for a track linear? I.e.: If you decrease frequency by half, you need about twice as many plots for a track?
No, it's not that linear but lower the frequency and longer the range, then the tracking becomes more difficult because of very large number of detections (plots) generated by clutter (like ground, sea, rain, EW, chaff). Another thing that affects is the low resolution of low band radars. So the errors and uncertainty are far larger in each individual detections and thus higher number of plots are needed for reliable track initiation and confirmation. Usually X-band radars can initiate tracking from only 2-3 consecutive detections (plots). L-band surveillance radars tend to need 5-10 consecutive plots for reliable track initiation. It could be done with lower number of consecutive plots, but then false tracks from clutter become serious problem. Even with higher number of plots, there tend to be false tracks especially in older systems with less capable signal processing and filtering.
michaelemouse wrote:From what I understand, while absence of detectability or absence of track are desired, stealth is mainly about decreasing the range or probability of attaining a sufficiently timely and precise targeting solution. I presume the range cell resolution is usually precise enough but the azimuth/elevation cells might be much larger than the effective damage area of a warhead. Even with a precise-enough targeting solution, you need to update it often enough if the target takes evasive maneuvers, otherwise it's like playing an online first-person shooter with a 5FPS framerate. Add to that that a stealth strike aircraft would likely be supported by EW to generate even more false tracks and survivability might be much increased.
How would a system trying to take down an F-117 or similar go about distinguishing between true target tracks, false target tracks from jamming and false target tracks from unintentional noise?
That's true. The real F-117 shootdown in 1999 shows one good example. P-18 radar operating in VHF frequencies managed to detect F-117 first at about 50-60 km out according to serbian operators and got stable plots from 25 km away. There is no automatic tracker in that version of P-18, so this is basically where they were tracking (by hand) the F-117. As the detection range for 2.5 square meter target is >= 175 km with this radar according to some specs I could find (about their upgrades), it's clear that even F-117 stealth features really are effective even against VHF radars. They may not be as effective as in higher frequencies, but still effective.