Non-coherent transmitted reference (TR) scheme is a popular technique in ultra-wideband (UWB) communications. Comparisons of the TR receiver with the coherent UWB receiver have not yet been studied in terms of their acquisition performance. In this paper, the acquisition performance of coherent and TR receivers is analyzed over a common acquisition stage. Closed-form expressions of their average acquisition time (AAT) and false-alarm rate (FAR) are derived, which enables the AAT comparison under the same FAR threshold. Results show that the TR receiver has a better acquisition performance than the coherent receiver despite of its noisy template signal and energy loss on pilot signals.