A COMPACT PROGRAMMABLE LASER DOPPLER VELOCIMETER FOR MARINE APPLICATIONS

THIS PROPOSAL DESCRIBES A PROGRAM TO DEVELOP A COMPACT, RUGGED, AND AUTONOMOUS PROGRAMMABLE LASER DOPPLER VELOCIMETER (LDV) FOR MARINE APPLICATIONS. THE SYSTEM WILL INCLUDE TWO MAJOR INNOVATIONS IN LDV TECHNOLOGY: A PROGRAMMABLE DIGITAL SIGNAL PROCESSOR (DSP), AND A PULSED LASER DIODE. THE DSP PROVIDES THE HIGHEST COMPUTATIONAL POWER AND PROGRAMMABILITY IN A COMPACT SIZE ALLOWING THE IMPLEMENTATION OF INTELLIGENT ALGORITHMS WHICH PROCESS LOW SIGNAL LEVELS AND COMPLEX SIGNALS ARISING FROM LIVE MARINE PARTICLES. THE PULSED LASER DIODE OFFERS THE POTENTIAL OF PROVIDING OPTIMUM SIGNAL TO NOISE BY CONCENTRATING ALL OF ITS POWER DURING THE TIMES WHEN THE DIGITIZER IN ON, THUS, IT PROVIDES LARGE BURSTS OF ENERGY DURING THESE SHORT INTERVALS. PULSED LASER DIODES ALSO HAVE THE POTENTIAL OF PROVIDING VERY SIMPLE TWO-VELOCITY COMPONENT SYSTEMS SINCE TWO SETS OF FRINGES CAN BE SEQUENTIALLY PULSED AND THE ELECTRONICS CAN BE SYNCHRONIZED TO TRACK THEM. THE SIZING OF THE PARTICLES WILL ALSO BE ATTEMPED FROM MIE SCATTERED LIGHT. THIS ADDED INFORMATION MAY NOT ALWAYS BE POSSIBLE DUE TO THE PRESENCE OF MULTIPLE PARTICLES AND COMPLEX MARINE SHAPES. THESE CASES WILL BE RECOGNIZTED BY THE DSP AND THE INSTRUMENT WILL ONLY PROVIDE THE VELOCITY INFORMATION.