The characteristics of an ultrasonic instrument, the bistatic acoustic Doppler velocity profiler (ADVP) are described. The bislatic system can measure profiles of two components of the instantaneous velocity vector with no restrictions on the flow conditions. Results of the bistatic ADVP measurements of water velocity and turbulence in uniform flow in laboratory open channels, were found to coincide well with the laws for mean velocity, variance and Reynold's stress. This indicates that the turbulence scales are sufficiently resolved in the ADVP measurements. Two-dimensional flow patterns derived from the ADVP measurements demonstrate the presence of coherent structures. The instrument was found to be a useful research tool for non-intrusive and accurate instantaneous profile measurements under turbulent flow conditions unaffected by water quality.