基于带限随机信号相位谱的分数延时估计方法

传统延时估计方法的精度受采样间隔的限制。为提高精度，提出一种新的适用于宽带信号的分数延时估计方法。该方法将周期图法与抛物线插值应用于带限随机信号的互相关谱，可以获得连续的延时估计。文中通过一系列仿真实验对该方法与其他分数延时估计方法的性能进行比较。结果表明，该方法的性能优于其他估计方法，在信噪比较高的情况下，可以接近克拉美罗下界。由于发射信号具有宽带和随机的特点，该方法适用于低截获概率雷达。

SUBSAMPLE TIME DELAY ESTIMATION BASED ON PHASE SPECTRUM OF BAND LIMITED STOCHASTIC SIGNALS

The accuracy of conventional time delay estimation (TDE) algorithms is limited by the sampling interval. A novel algorithm of subsample TDE suitable for wideband signals is presented to improve the accuracy. This algorithm applies periodogram and parabolic interpolation to the cross correlation spectrum of band limited stochastic signals, and can obtain a continuous time delay estimator. Simulations are carried out to compare the performance of the proposed algorithm with that of other subsample TDE algorithms. Results show that the proposed algorithm outperforms other algorithms and reachs the Cramer-Rao lower bound (CRLB) at a high signalto-noise ratio. For the wideband characteristic and the randomness of the transmitting signal. the proposed algorithm is suitable for the low probability of intercept radars.