I mean a compressed pulse consist of several different frequencies (wide bandwidth) , which mean the radar receiver will have to listence in wider frequency range ( bandwidth ), so more percentage of jamming power will get into radar receiver and increase J/S ratio. For example : if radar can operate between 8-12 Ghz , 4 Ghz total bandwidth , assuming jammer distributed energy over the whole range, for a normal pulse with bandwidth of only 1 Mhz ,then only 0.025% of jamming power will get into radar receiver. For a compressed pulse with 1 Ghz bandwidth ,about 25% of jamming power will get into radar receiver. That a significant different IMHO.
Yes, but that is assuming that you will have to spread jamming power allover the spectrum, which is true if you want to permanently jam the radar. LPI radars use waveforms, frequency hoping etc, but the number of patterns is not infinite. These patterns will be recorded by DRFM and used in highly parallel correlators chips.When an identical signal will happen, it will be recognized and jamming will happen. Potentially killing the kill chain and the track so as whole acquisition process has to restart (well that’s what i understood from an expert).
So we know that if a jammer doesn’t know exact frequency the radar transmitting ( in case of frequency hoping ) , it will have to spread it power over the whole frequency range that radar may operate , and that will reduce J/S ratio. Which mean the wider the total bandwidth of radar or/and the smaller the bandwidth of its pulse, the harder it would be to jam that radar we also know that if the jamming signal doesnt contain pulse compression waveform , the J/S ratio will be reduced due to compression factor.However, the more complex the waveform is , the wider the bandwidth of the pulse need to be. Does that mean frequency hoping and pulse compression counter each other somewhat ?
source? (date?)
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