In wideband (high range resolution) radar, moving targets migrate along the range during the coherent processing interval (CPI). In this paper, we propose to use the information brought by this migration to alleviate the velocity ambiguity that occurs in low pulse repetition frequency (PRF) mode. More specifically, a Bayesian algorithm is implemented to give a sparse representation of the received signal while unfolding properly the range-velocity map. Though computationally intensive, the algorithm demonstrates the possibility of designing a non-ambiguous radar mode with a single PRF in case of a multi-target scenario.