Thanks
WHat I meant was that some ASM are built for combat specifically in littorals like the sweedish RB40, komoron and penguin but the Harpoon seems like built more for blue water naval battles so was wondering how effective it was in the clutter

Performance in the littorals from the seeker in question was modest at best. In truth that was the same for most ARH’s of the day and I’d assume still many today. Harpoon was originally conceived as a weapon to engage surfaced submarines (preparing cruise missile launches) so, while the target could be reasonably modest in absolute RCS terms (compared to a frigate etc) it would be a high contrast target i.e low….low….low….high….high….low and you were flying for the high bit….in very basic terms. The seekers were capable of working with that. Clutter would be a problem though….you can run as many clever algorythms you like on the returning pulses but you’ll never get much more resolution than the frequency allows. If you widen your seeker arc you have to process more return signal so resolution suffers and if you narrow it you limit your FoV so, on seeker activation, you have lower chances of target capture…or a need to have a very definite target fix prior to launch which makes the weapon harder to deploy.

An attempt to get more target definition with this kind of seeker, that could have aided littorals engagement, was made possible by use of range profiling. I’m not sure its public source which missiles had/have the capability….though there is US documentation online discussing the technique in reference to antiship missiles and published in the early-80’s timeframe. Dont know if, perhaps, Mercurius might know whats public source and whats not?. I know there was one other similar system that definitely could do range profiling that was operational in the wider 80’s timeframe.

Range profiling effectively set a very narrow rangegate in the seeker head of maybe a few tens of metres and then advanced that rangegate toward a contact to attempt to determine the RF profile of the target by looking at small chunks of it and how high the return signal is. If target aspect is correct it can be possible to pickout a dual peak profile of a warship foremast/mainmast or for’d superstructure and after deckhouse/hangar. With that it could be possible to separate warship from tanker or chaff cloud from warship….but the wrong target aspect or a profile ashore matching a ‘familiar’ pattern could send the missile off on a tangent. So not really any great shakes and not a great enabler for shooting active radar missiles into cluttered waters.