sound and flash ranging

sound and flash ranging

[¦sau̇nd ən ¦flash ′rānj·iŋ]
(ordnance)
Two distinct and separate but supplementary systems of locating enemy weapons and, secondarily, adjusting friendly counterfire: by observation by sonic devices on the sound produced by the enemy weapon in firing or by the friendly projectile in exploding; or by visual observation of the flash produced or of the point of burst of the enemy weapon or friendly projectile.