The Propagator Method (PM) is extended to application in super-resolution time-of-arrival (TOA) estimation for ultra wideband (UWB) system, which need not any eigen- decomposition calculation and reduce the computation load in practical UWB implementation. Then TOA estimation is investigated in the presence of correlated complex fading amplitudes for UWB rays. In the UWB channel models proposed so far, an assumption is given that the amplitudes are statistically independent or scarcely correlated. However, they may be correlated in practical UWB indoor surrounding, which lead to rank-deficiency of the correlation matrix, and the performance is seriously descended. In the paper, array spatial smoothing is extended to solve the above problem based on forward-backward frequency-domain smoothing (FBFDS). The proposed method can reduce the computation complexity and improve the performance of closely delays estimation when the delays of arrival are smaller than a UWB pulse duration. The simulation results of the proposed algorithm are given.