Identification of penetration layers based on Choi-Williams distribution

There is an oscillation signal superposition on measured acceleration signals during the process of penetrating multilayer hard targets, which can cause a misjudgement of the target layer number. To overcome the above problem, a time-frequency analysis method was adopted to study the Choi-Williams energy distribution features of the acceleration signals in the directions of projectile main axes. Based on the energy distribution of the acceleration signals during penetration process, a target layer identification method was put forward. The acceleration data were processed, and these data were measured from the penetration of eight concrete slabs with the same thickness by a projectile. The processed results show that the layer identification method put forward can identify the layer number rapidly and accurately. The problem, that the low-pass filtering method can not acquire the accurate layer number, was solved. So the layer identification method put forward can provide basis for the real-time control of initiation positions.