一种改进的Rife算法及其在无线电干涉测量中的应用

An Improved Rife Algorithm and Its Application in the Radio Interferometry

信号频率和相位是连线干涉测量(CEI)以及甚长基线干涉测量(VLBI)本地相关处理的主要测量元素,其中相位测量精度直接影响着无线电测量精度。在对Rife算法及其改进算法(M-Rife算法)分析的基础上,提出一种新的改进算法(I-Rife算法)。该算法通过增加一次固定频移,解决了M-Rife算法在信号频率位于整数倍FFT频率分辨率附近时频移方向容易出错的问题,估计性能有所提高。对I-Rife算法的误差性能进行分析,其结果表明,改进算法的频率估计误差、相位估计误差分别约为克拉美-罗下限(CRLB)的1.0073倍、2.3562倍。最后,通过蒙特卡罗仿真和无线电干涉测量试验对所提算法的性能进行了验证。

The signal frequency and phase are main measurement parameters in the CEI and VLBI,especially the phaseaccuracy directly affects the measurement accuracy of radio interferometry.Therefore,on the basis of analysis on Rifealgorithm and one of its improved algorithms(M-Rife),a novel improved algorithm(I-Rife)is proposed.By adding a fixedfrequency shift,the new algorithm solves the problem that the frequency shift direction is easy to misjudge when the signalfrequency is about integral multiple of FFT frequency resolution,so that it can obtain a better estimation performance.Theestimation error of the proposed algorithm is deduced.The analysis results show that the frequency and phase estimation errorsare nearly1.0073and2.3562times of CRLB respectively.Finally the performance of the proposed algorithm is verified by theMonte Caro simulations and a radio interferometry experiment.