PINHOLE YAWSONDE SENSOR

Abstract

The yawsonde is a device used at the U.S. Army Research Laboratory (ARL) to investigate the in-flight behavior of spinning projectiles. The standard yawsonde consists of a pair of solar cells and slits that respond to solar rays. The sun is used as an inertial reference to measure the pitching and yawing motions of the projectile. An FM telemetry package transmits the sensor data to a ground receiving station for analysis. The standard yawsonde package is housed in an M577-type artillery fuse body. The spinning motion of the projectile serves as the sampling rate for the measurements. When the spin rate is not significantly higher than the yaw rate, multiple sets of sensors must be used to effectively increase the sampling rate. The pinhole yawsonde sensor was developed for projectiles that require multiple sets of sensors in a very limited space. This pinhole yawsonde consists of a number of sensors located behind pinholes placed around the projectile's circumference. Since each pinhole makes a yaw measurement, many measurements, or samples, are taken with each projectile spin revolution. More pinhole sensors may be added to increase the measurement sampling rate. One application of this yawsonde is to aid in evaluating the performance of tactical devices and inertial systems onboard projectiles with limited space for instrumentation.