分数阶傅里叶变换的多项式相位信号DOA估计

针对多项式相位信号波达方向(DOA)估计研究较少的问题，提出了一种基于分数阶傅里 叶变换(FRFT)的多项式相位信号(PPS)的DOA估计算法。该算法首先通过多项式相位变换，估 计出PPS的最高阶相位系数，从而可以消除最高阶项。运用这一降阶思想，依次消除高阶项 ，这样PPS可降为线性调频(LFM)信号,然后将宽带的LFM信号转化为分数阶Fourier域窄带的 平稳信号。在相应的分数阶Fourier域，运用求根MUSIC算法对信号进行DOA估计,从而把LFM 信号的DOA估计推广到了PPS的DOA估计。理论分析和仿真实验表明，该方法能很好地估计出P PS的DOA，并且简洁。

DOA Estimation of Polynomial Phase Signal Based on Fractional Fourier Transform

According to the fact that DOA estimation of Polynomial Phase Signa l(PPS) is less studied, a novel algorithm for the direction of arrival (DOA) est imati on of PPS based on the fractional Fourier tra nsform (FRFT) is introduced. In this algorithm,the high order phase coefficient of PPS is estimate d by polynomial phase transform, so that the high order phase coefficient can b e removed. Using this method, high order phase coefficient can be eliminated sequentially, so PPS can be redu ced to Linear Frequency Modulation(LFM),and then the LFM signal is transformed t o narrowband stationary signal of fractional Fourier domain. In the appropriate fractional Fourier(FRF) domain, DOA estimation can be estimated by using the Roo t-MUSIC algorithm, so DOA estimation of the LFM signal is extended to the PPS. T heoretical analysis and simulation results demonstrate that the method can estim ate the DOA of PPS well and simply.