Rapid acquisition of ultra-wideband (UWB) signals in multipath channels is a challenging task due to the following reasons. First, fine time resolution of UWB signals introduces a large search space. Second, due to the very low power of the received signal, it needs to be observed for a long time to make a reliable decision. These two problems make the process of acquisition unacceptably slow. In this paper, we introduce a new two-stage algorithm to reduce the search space and consequently the acquisition time. The performance of the proposed method is analytically evaluated in terms of mean acquisition time and the results are validated through simulations. The results show a significant improvement in the speed of acquisition with no additional complexity.