IN-FLIGHT FLOW VELOCITY SENSOR

EXISTING AIRSPEED SENSORS ARE BOUND TO THE AIRFRAME SURFACE AND SAMPLE THE FLOW WITHIN THE BOW-WAVE PERTURBATION ZONE WHERE AIRSPEED AND ANGLE-OF-ATTACK INFORMATION ARE INTERMIXED. THIS INNOVATION COMBINES RECENTLY DEVELOPED TECHNOLOGIES THAT ENABLE FLOW MEASUREMENTS OFF THE AIRFRAME SURFACE IN THE FREESTREAM BEYOND THE BOW-WAVE. NARROW-BAND DIODE LASER TECHNOLOGY COUPLED WITH HIGH-POWER LASER DIODES AND AN INNOVATIVE, DOUBLE-HETERODYNE DETECTION SYSTEM ENABLES MEASUREMENT OF THE DOPPLER SHIFT OF THE LASER LIGHT BACKSCATTERED FROM THE AEROSOL CONTENT OF THE ATMOSPHERE. THREE SUCH SENSORS CAN BE USED TO DETERMINE THE MAGNITUDE AND VECTOR DIRECTION OF THE AIR VELOCITY, YIELDING BOTH AIRSPEED AND ANGLE-OF-ATTACK, WITH A SMALL ADDITION IN ELECTRONICS, AN ICE/SNOW DISCRIMINATING DETECTOR COULD ALSO BE ADDED TO THE SYSTEM TO WARN OF DANGEROUS LEVELS OF ICE CRYSTALS IN THE FREESTREAM. THIS SYSTEM WILL BE ALL-SOLID-STATE AND, THEREFORE, COMPACT, EFFICIENT, AND RUGGED ENOUGH FOR THE INFLIGHT APPLICATION. THE AVAILABLE DYNAMIC RANGE EXTENDS FROM LOW SPEED TO MACH 18, DEPENDING ON THE ELECTRONICS DESIGN. THE PHASE I OBJECTIVE IS TO MEASURE THE SIGNAL-TO-NOISE RATIO OF A BREAD-BOARD SYSTEM. EXISTING AIRSPEED SENSORS ARE BOUND TO THE AIRFRAME SURFACE AND SAMPLE THE FLOW WITHIN THE BOW-WAVE PERTURBATION ZONE WHERE AIRSPEED AND ANGLE-OF-ATTACK INFORMATION ARE INTERMIXED. THIS INNOVATION COMBINES RECENTLY DEVELOPED TECHNOLOGIES THAT ENABLE FLOW MEASUREMENTS OFF THE AIRFRAME SURFACE IN THE FREESTREAM BEYOND THE BOW-WAVE. NARROW-BAND DIODE LASER TECHNOLOGY COUPLED WITH HIGH-POWER LASER DIODES AND AN INNOVATIVE, DOUBLE-HETERODYNE DETECTION SYSTEM ENABLES MEASUREMENT OF THE DOPPLER SHIFT OF THE LASER LIGHT BACKSCATTERED FROM THE AEROSOL CONTENT OF THE ATMOSPHERE. THREE SUCH SENSORS CAN BE USED TO DETERMINE THE MAGNITUDE AND VECTOR DIRECTION OF THE AIR VELOCITY, YIELDING BOTH AIRSPEED AND ANGLE-OF-ATTACK, WITH A SMALL ADDITION IN ELECTRONICS, AN ICE/SNOW DISCRIMINATING DETECTOR COULD ALSO BE ADDED TO THE SYSTEM TO WARN OF DANGEROUS LEVELS OF ICE CRYSTALS IN THE FREESTREAM. THIS SYSTEM WILL BE ALL-SOLID-STATE AND, THEREFORE, COMPACT, EFFICIENT, AND RUGGED ENOUGH FOR THE INFLIGHT APPLICATION. THE AVAILABLE DYNAMIC RANGE EXTENDS FROM LOW SPEED TO MACH 18, DEPENDING ON THE ELECTRONICS DESIGN. THE PHASE I OBJECTIVE IS TO MEASURE THE SIGNAL-TO-NOISE RATIO OF A BREAD-BOARD SYSTEM.