In this paper, a novel synchronization algorithm dispensing with searching is proposed for UWB communications. By adopting a stream of alternating orthogonal pulses, frame-level synchronization can be achieved without training sequence involved. Without any searching procedure, the timing offset estimator is obtained in a closed form, therefore considerably reducing the synchronization time. Simulations and comparisons confirm that the proposed scheme outperforms the existing alternative in terms of normalized mean square error (NMSE) and bit error rate (BER).