The present invention is directed to signal processing means for detecting and discriminating between geological layers encountered by kinetic energy subterranean vehicles in flight (terra-craft), using a raw signal representing deceleration of the terra-craft. The signal processing means uses autocorrelation and filtering to amplify the rate of deceleration, allowing the same to be compared to extensive data compiled for the US government regarding rates of deceleration in known materials, using various craft geometry. In this way, the unknown material encountered by the terra-craft can be identified by comparing the deceleration of the craft through a layer of material to the known data for the craft geometry. The signal processing means may further include a plurality of circuits to detect and annunciate varying layers in a media, and to track in real time the location of the projectile.