PROJECTILE YAW SENSING TECHNOLOGY

THE COLLECTION OF IN-FLIGHT YAW AND SPIN MOTION INFORMATION FOR PROJECTILES IS CRITICAL TO THE EVALUATION OF SYSTEM PERFORMANCE. PRIOR TO THE ACTUAL MANUFACTURING AND TESTING OF A NEW OR IMPROVED PROJECTILE DESIGN, THE AERODYNAMIC COEFFICIENTS USED IN THE TRAJECTORY SIMULATIONS ARE GENERATED WITH THE USE OF SEMI-EMPIRICAL CODES. THE ACCURACY OF THESE CODES DEPENDS UPON THE DEGREE TO WHICH THE NEW DESIGN DEVIATES FROM THE EXISTING DESIGNS. AS THE FINAL STEP, THE PROJECTILE CONFIGURATION IS BUILT AND TESTED TO DETERMINE THE ACTUAL AERODYNAMIC CHARACTERISTICS. PRECISE MEASUREMENT OF SPIN RATE AND YAW ARE CRITICAL TO THE DESIGN PROCESS. THIS IN-FLIGHT YAW AND SPIN MOTION MEASUREMENT OF ARTILLERY SHELLS AND OTHER MUNITIONS IS FREQUENCY ACCOMPLISHED BY THE USE OF OPTICAL SENSING AND STANDARD RADIO-FREQUENCY TELEMETRY TECHNIQUES. THE STANDARD SYSTEM THAT IS USED SENSES THE PASSAGE OF THE SUN AS THE PROJECTILE SPINS AND IS CALLED A YAWSONDE. THIS METHOD IS OBVIOUSLY RESTRICTED BY WEATHER CONDITIONS AND THE TIME WINDOW, BASED UPON DIRECTION OF FIRE, QUADRANT ELEVATION AND EPHEMERIS DATA, IN WHICH IT CAN OPERATE. THE TECHNIQUE THAT IS DESCRIBED IN THIS PROPOSAL USES A SINGLE STANDARD RATE GYROSCOPE OR ACCELEROMETER OF THE TYPE THAT IS HARDENED AND PROVEN FOR USE IN GUIDED ARTILLERY MUNITIONS TO CHARACTERIZE ALL OF THE REQUIRED MOTIONS WITH GREATER VERSATILITY THAN THE CURRENT YAWSONDE.