err, a fire direction sensor would not help much once the missile (F&F) has been launched. Assuming there are several missile teams (of 1 or two).
In the war like we are seeing in Ukraine some Russian commentators (well, not many, as they will be taken down) have said that in the war of attrition (not counting the artillery effect, which is what we are seeing now) the max. Russian number of 400k (some expended by now, not so much in men but in NCOs and officers) may need to face an army of 1 mln .... one in eight (where did I get that number from?) toting Javelin or something for a closer range. But equally deadly