Abstract: An apparatus and method for identifying the path/time relationships of a projectile within a weapon barrel, even upon live firing, includes a coupling element having at least two openings in a sidewall thereof through which a generated electromagnetic wave is divided and then introduced into the barrel. The divided wave includes wave parts that propagate toward and away from the barrel, the parts propagating toward the barrel adding up and being introduced into the barrel while the parts propagating away from the barrel cancel each other out. The wave reflects off from the projectile and is then received after undergoing an inverse division.