Abstract: It is too difficult to capture all flying shrapnel and measure its speed，because the number of shrapnel is uncertain and the velocity of all shrapnel is various，when shell exploded.The paper has designed a target，which can capture all shrapnel coming from the exploded shell.According to the circuit of every area of the target，it gives a formula of the output signal.With a data acquisition equipment，it can acquire the signal data.Analyzing every signal segment with a short-time Fourier transform method，according to the amplitude-frequency characters of it，it can find the time point when shrapnel touched the target at the first time.Then it can calculate the shrapnel’s flying time from exploded position to the target.Measuring the distance from exploded position to the target，it can calculate the velocity of shrapnel.The paper gives a example，which can prove the design is feasible and correct.

Key words: speed measurement, time-frequency analysis, short-time Fourier transform, data acquisition

摘要： 炮弹爆炸产生弹片的数量不确定，弹片飞行方向和速率也各不相同，捕获所有弹片并测量其飞行速率的方法较复杂。鉴于此，设计了能捕获炮弹爆炸产生弹片的目标靶，并考虑目标靶靶区的实际电路特性，分析了目标靶靶区输出的信号特点。采用高速数据采集设备采集炮弹爆炸时刻至弹片全部穿过目标靶的一段时间内的各靶区输出信号，对该信号进行短时Fourier变换，分析各时间片段的信号幅频特性。再根据各时间片段的信号幅频特征，确定弹片刚触靶时刻点，由此计算得出弹片从爆炸点至触靶的飞行时间，测得爆炸点到目标靶的距离，就可计算得出弹片的飞行速率。最后举了个实例验证了该设计方案的可行性和正确性。

关键词: 速率测量, 时频分析, 短时Fourier变换, 数据采集