In this paper, the bit error rate (BER) performance for an ultra-wide bandwidth (UWB) impulse radio in an additive white Gaussian noise (AWGN) transmission channel and with Gaussian jitter is estimated. The assumed receiver combines the received pulses to increase the signal to noise ratio (SNR) and correlates the received signal with a locally generated template. The resulting performances are discussed separately for a large number and a small number of combined pulses. In the former case, the BER is derived analytically and verified using numerical simulations, and in the latter case, lower bounds for the BER are provided for low and large SNRs. Simulation results are shown to approach asymptotically the provided bounds.