The goal of this paper is to highlight the significance of the timing acquisition problem in ultra-wideband (UWB) communication systems and discuss efficient solutions to the problem. We discuss how the distinguishing features of UWB communication systems, such as their wide bandwidth and low transmission power constraints, are responsible for making the acquisition of UWB signals a difficult task. A survey of the current approaches to UWB signal acquisition is also given. In addition, we discuss some of the issues and challenges in UWB signal acquisition which may not have received sufficient attention in existing literature.