改进型过零点测频法在常规弹药转速提取中的应用

An Improved Method of Frequency Measurement Based on Zero-Crossing in Rotating Speed Measurement of Conventional Ammunition

针对高速旋转弹转速高、传统微惯性器件量程小的问题,提出采用磁阻传感器测量高转速常规弹药在飞行过程中的转速。以磁测信号为研究对象,首先分析传统的"线性插值"过零点测频法和基于"最小二乘"的改进型过零点测频法提取弹丸转速的原理,并作MATLAB仿真;然后研究信噪比对两种算法测量误差的影响,得出"最小二乘"过零点测频法用于常规弹药转速提取时误差较小;此外,研究了使该改进型过零点测频法误差达到最小的相位角选取原则;最后采用此方法对某型号常规炮弹的实弹数据进行时频分析,得出炮弹全弹道转速信息。

According to the higher rotating speed of conventional ammunition and the shorter measuring range of tra- ditional micro-inertial device, this paper presents a rotating speed measurement method of conventional ammunition which bases on magnetoresistive sensor. Taking magnetic survey signal as the research object, first the principle of rotating speed measurement based on linear interpolation and least square methods was analyzed. It was discussed how the SNR affected the measurement error. And it was demonstrated that the error is small compared with the traditional method. In addition, the selection principle of phase angle that makes the errors least is given. Finally, this improved method is used to make time frequency analysis of the data of some type conventional ammunition.