Synchronization is a key issue for ultra-wideband (UWB) radios. Coherent UWB receivers, which correlate the received signal with a well-designed template, have very stringent requirements for synchronization accuracy, leading to a long synchronization time. Various acquisition/synchronization algorithms have been proposed to enhance the synchronization speed of UWB receivers, but many of them only focus on a partial synchronization process, and performance analysis in a practical scenario is usually not provided. In this paper, we propose a complete acquisition algorithm for coherent UWB receivers, which includes both pulse-acquisition and symbol-level synchronization (SLS) stages. Practical error-resistant approaches are developed to combat the synchronization error. Detailed analysis based on the finite state machine and flow graph theories is carried out to evaluate its performance, and parameter selections that minimize the average acquisition time are discussed. The proposed algorithm is shown to have enhanced efficiency compared to separate pulse-acquisition and SLS algorithms. Simulations corroborate our theoretical results.