低信噪比信号相位差检测算法优化设计与实现

The Design and Implementation of Algorithm to Optimize the Phase Difference Detection in Low SNR

针对导弹自动驾驶仪回路测试中相位差的测量,介绍和分析了目前常用的测量相位差的三种算法,即零点比较法、频域分析法和相关分析法的原理,并运用虚拟仪器技术分别实现了这三种算法。通过仿真,分析了这三种算法各自的优缺点及适用场合。采用相关分析法测量信号的相位差,具有抗干扰能力强和响应速度快等优点,因此,本文重点分析了相关分析法,并针对信号噪声比较大,即低信噪比情况,对相关分析法进行了优化设计与实现。通过仿真验证表明,改进后的相关分析法能在低信噪比情况下有效提高信号相位差检测精度,使用该算法在对某型号导弹驾驶仪回路实际测试数据进行分析和计算后,进一步验证了该算法的有效性。

Three methods such as zero across and FFT and correlation analysis are introduced to measure phase difference for the test of missile automatic pilot.The virtual instrument based on LabView is used to realize the three methods.The advantage and disadvantage for these three methods are analyzed through simulation.The phase difference measurement by correlation analysis has the advantages of high precision and strong anti-jamming,so this paper emphasis on correlation analysis.Correlation analysis arithmetic is optimized and realized in low SNR.Through simulation,the ameliorated method of correlation can improve the test accuracy of phase difference efficiently.The algorithm has been applied to a missile automatic pilot testing system,the results has shown the validity of the algorithm.