first coil means for electromagnetically sensing relative proximity and left and right displacement of said projectile in terms of {TAIL ~ currents} induced by {HEAD ~ the mechanical motion} of said projectile 
first coil means for electromagnetically sensing relative proximity and left and right displacement of said projectile in terms of { TAIL ~ currents } induced by { HEAD ~ the mechanical motion } of said projectile
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH