An acquisition channel (20) includes a UWB sampler block (21) coupled to an analog integration block (22) further coupled to a digital integration block (24) via an analog/digital converter (23). For each range cell the UWB sampler block (21) repeatedly samples the received signal by tuning the sampling instants to the range cells to be acquired. The acquisition channel (20) is further coupled to a processor (26) and a database (25).