One of the most popular techniques for signal acquisition which has also been used in spread spectrum systems is linear serial search method. Although the simple linear serial search results in a relatively low speed acquisition time in the context of UWB systems, it keeps its importance when it is used as a comparison mean to other improved methods and also when used in a hybrid manner. No exact analysis, however, has been performed yet for serial acquisition of UWB signals in realistic multipath channels. In this paper, we perform an exact analysis of the method in the channel model adopted by the IEEE 802.15.3a standardization group. The results of the analysis are also validated through computer simulations.