中文摘要：

高射速火炮由于射速高及连发时炮口连续火焰等影响，传统的出膛时刻检测方法已经失效。通过分析高射速火炮弹丸的回波信号特性，提出基于短时傅里叶变换的弹丸回波分析方法，给出了相应的窗函数、窗口宽度、帧移长度关键参量的设计原则。通过理论分析和实测数据验证了该方法可以得到射速在7500发/min的高射速火炮近似的系统时间零点，同时为获取精准的系统时间零点奠定基础，并为工程应用提供有益的参考。

英文摘要：

Because of the problems that the proj ectile muzzle velocity of the high firing rate gun is fast,radio frequency is high,and the muzzle flame is companying when the gun carries out the bursts of fire,the traditional test methods to obtain the zero time are invalid.A time-frequency analysis method based on Short Time Fourier Transform （STFT）was put forward by means of analyzing the proj ectile echo signal characteristics of high firing rate gun.The design principles of key parameters such as window function, window width and frame shift length about the STFT were given.Through the theory analysis and the measured data validation,the proposed method is feasible to get the approximate system zero time under the condition of the gun firing at rate of fire about 7500 rounds per minute,and the study results can lay foundation for obtaining the accurate system zero time,and it can also provide useful reference for engineering applications.