VELOCIMETERS

THE NEED TO DEVELOP IMPROVED SIGNAL PROCESSORS TO ENHANCE THE S/N OF MULTICOMPONENT LDA SYSTEMS IS CRUCIAL TO FUNDAMENTAL STUDIES CONCERNING HELICOPTER AND OTHER AERODYNAMIC BODIES. ALTHOUGH THERE HAS BEEN A RAPID DEVELOPMENT OF LDA TECHNIQUES IN THE PAST DECADE, LITTLE HASBEEN DONE TO IMPROVE THE METHODS OF SIGNAL PROCESSING. THISPROPOSAL INTRODUCES FAST DIGITAL PROCESSING OF THE LDA SIGNAL AS A STRONG ALTERNATIVE TO THE PRESENTLY USED ANALOGUE TECHNIQUES. AUTO-CORRELATION, FAST FOURIER TRANSFORMS (FFT) AND OTHER SIGNAL ENHANCEMENT TECHNQIUES AREAPPLIED TO THE RECORDED SIGNALS TO ENHANCE THE INPUT SIGNAL AND TO EXTRACT VELOCITY INFORMATION FROM SIGNAL LEVELS ON THE ORDER OF BACKGROUND NOISE. IT IS EXPECTED THAT UNDER PHASE I, THE TECHNIQUE WILL BE DEVELOPED INCLUDING BOTH THE SOFTWARE AND BRASSBOARD HARDWARE. A PROOF-OF-CONCEPT EXPERIMENT WILL THEN FOLLOW. PHASE II WILL INVOLVE THE DEVELOPMENT OF A MULTI-COMPONENT SIGNAL PROCESSING SYSTEM WHICH WILL BE INTEGRATED TO AN EXISTING LDA SYSTEM AT NASA.