Cross-beam laser velocimetry using Bragg shift and photon correlation has been utilized to measure a weak secondary flow component in the presence of strong primary flow at right angles to it. To obtain this velocity component with adequate accuracy, the apparent Doppler frequency was determined by Fourier transformation of the correlogram followed by two steps of interpolating correction. The remaining frequency error may be as little as 10-2jfwhere integral multiples of jfare the abscissa values for which the discrete Fourier transform is given. Finally a method is described which allows precise orientation of the cross-beam fringes at right angles to the secondary flow component; it makes use of symmetry properties of the flow in question.