机载平台相差变化率的多通道相移检测

Method Obtaining Phase-Difference Rate by Multichannel Phase Difference Detection on Airborne Platform

摘要: 基于相移与频移间的函数关系，提出了一种通过多通道相移测量获得机载平台相差变化率的新方法。首先，利用在由相位干涉测向所给出的到达角与在多普勒频移方程中所包含的前置角之间的互余关系，描述了频移的相差检测方法。然后进一步通过对距离–相差方程的微分导出了相差变化率的多通道相差检测方法，并同时亦从理论上证明了相位变化率是可通过测频而获得。在此基础上，由相差变化率测距的方法间接验证了基于多通道相差测量的相差变化率的计算公式的正确性。尽管误差分析表明基于多通道相差测量所获得的相差变化率的测量精度还较差，但与通过双通道鉴相测频获取相位差变化率的测量方法相比，多通道相差检测可避免因被测量的频差间隔值太小，等效测量时间很短，使测量误差变得很大的问题。同时，多通道相差检测的优点还在于一次测量即可实时获得相差变化率，因无需通过延长观察时间来积累足够的相位差序列的长度，故无需限定载机的运动速度。

Abstract: Based on the function relationship between phase shift and Doppler shift, this paper presents a new method obtained the phase-difference rate on airborne platform by measuring the phase shift in multichannel way. Firstly, the method that detects Doppler shift by measuring phase difference is described by making use of the mutually complementary relationship between the arrival angles obtained by direction finding based on phase interferometer and advance angle contained in Doppler shift equation. Further, the method detecting phase difference rate based on phase difference measurement is derived by differential for distance-phase difference equation. Meanwhile, it also proves theoretically that the phase difference rate can be obtained by frequency measurement. On this basis, according to the ranging method based on phase difference rate, this paper indirectly verified the correctness of the phase difference rate formula obtained based on the multi-channel phase difference measurement. Although the error analysis shows that the measurement accuracy obtained based on the multi-channel phase difference measurement is poor, multichannel phase detection can avoid the problem making measurement error worse since the space value of measured frequency difference is little and equivalent measuring time is shorter as compared with the measurement method of phase difference rate obtained by the frequency measurement based on two-channel phase demodulation. At the same time, because the phase difference rate can be obtained by single measurement in real time and the system dispenses with accumulating the adequate length of phase difference sequence by prolonging viewing time, there is no need to restrict the aircraft moving speed.