Some new missiles have GPS guidance to hit the target in its base. Because their are lot of buildings and ships there, they can't use radar.
Actually launching a Harpoon or other AShM at a target in port surrounded by other things like fishing boats or Piers etc would be a very rare thing that most AShMs will never have to deal with.
If you can find a target in a cluttered environment... identify it, and calculate its coordinates to use GPS guidance then good on you... with the flight time of missiles and the fact that targets can move I don't think GPS would be the sole method of guidance.
did the 80's version of harpoon have that feature ?
I rather doubt it. Harpoon finds its targets with its radar... which isn't perfect but should be good enough to distinguish a target ship compared with an island or sand bar.
Thanks for the explanation, was 80s version of harpoon capable of distinguishing targets in the littorals if there is a lot of rocks coves and cliffs ?
Lots of radar reflectors would make locating the target difficult but not totally impossible. The missiles brain would be not particularly sophisticated, but as shown in the Falklands war one problem not often discussed is that in war time you often put into service non military vessels... ie civilian vessels are put to use as troop transports or supply vessels and when the enemy start firing missiles at your ships like exocets then when you military vessels fire off chaff and decoys and jammers and the incoming missiles lose lock it is all together possible they might acquire those undefended civilian vessels and blow up your supply of heavy helicopters or ammo or your troop ships...
reason I asked was because I was interested in the capabilities of harpoon in service with Japanese navy in the 80s
Being subsonic it would have trouble against the Soviet navy, but against the Chinese navy of the period or pretty much any other navy in the region they should be capable.
Again... with the Falklands... the UK had Exocets in their own inventory so they should have been familiar with its capabilities yet they suffered.