Vector velocimeter

A vector velocimeter, comprising:

• a laser assembly for emission of a measurement beam with a wavelength for illumination of an object in a measurement volume with coherent light whereby a signal beam emanating from the object in the measurement volume is formed in response to illumination of the object by the measurement beam;
• a reference beam generator for generation of a reference beam;
• a detector system including a first detector arrangement arranged in such a way that the signal beam and the reference beam are incident upon the first detector arrangement with the reference beam propagating at a first angle θ relative to a signal beam, and wherein the first detector arrangement includes a first detector array of first detector elements, each of the first detector elements converting the intensity of the interfering signal beam and reference beam incident thereupon into a corresponding electronic detector element signal thereby generating an oscillating electronic detector element signal when the fringe pattern formed by the interfering signal beam and reference beam moves across the first detector array;
• and
• a signal processor configured to generate a velocity signal corresponding to a first velocity component of movement of the object in the measurement volume in the longitudinal direction of the measurement volume based on the electronic detector element signals from each of the first detector elements.