Phase Doppler signal filtering in two-wave laser Doppler anemometer

Onboard equipment of unmanned aerial vehicle (UAV) should be small-sized and have a minimum possible weight. This rigid requirement also applies to the onboard laser velocimetry (anemometer, laser Doppler anemometer (LDA)) which can be realized not only on the base of integral optics using, semiconductor lasers and nanotechnologies in the production of element base of LDA, but also on the base of new physical and technological solutions during the construction of LDA´s principal scheme. Simultaneous using of the phase-coherent spatial filtration of signals at different wavelengths, conditions´ fulfillment of optimal receiving provides achievement of relation signal/noise on the output of two-wave LDA at least at one order in comparison of known LDA´s schemes. It gives a possibility for significantly increasing of velocity measurement´s accuracy with the help of two-wave LDA´s new generation.