干涉仪相位差测量精度的匹配滤波理论解释

Match filtering theory interpretation for the measurement accuracy of interferometer phase difference

摘要:

针对干涉仪接收通道间信号的相位差测量精度问题，指出了传统计算公式的局限性，通过采用信号能量信噪比替代信号带内功率信噪比，引出了干涉仪接收通道间信号的相位差测量误差的标准差的理论计算公式。从去调制与匹配滤波的角度证明了该计算公式的普适性，并通过各种调制信号与脉冲串信号的仿真验证了理论分析的正确性，揭示了干涉仪通道间相位差测量误差的标准差与信号能量信噪比的平方根成反比。这一理论分析结果为干涉仪测向工程应用的精度指标计算与论证分析提供了普适性的指导。

Abstract:

The phase difference measurement accuracy for the channels receiving signals in the interferometer is discussed. After the limitations of the traditional formula are pointed out, a theoretical computation formula of the standard deviation for the phase difference measurement error of the channels receiving signals in the interferometer is proposed by using the signal energy SNR (Signal-to-Noise Ratio) instead of the in-band power SNR. In theory, the universality of the formula is proved from the point of view of demodulation and match filtering. And the correctness of the theoretical analysis is verified by the simulation for various modulated signals and pulse series signals. It reflects that the standard deviation of the phase difference measurement error for the channels receiving signals in the interferometer is inversely proportional to the square root of the signal energy SNR. This theoretical result provides a general guidance for the computation, demonstration and analysis of direction finding accuracy index in interferometer engineering application.