Determining inertial orientation of a spinning body with body-fixed sensors

A methodology for determining absolute inertial angular orientation of a spinning body is demonstrated utilizing independent angular measurements for two arbitrary body- fixed sensor systems. A particular application is denoted utilizing Army Research Laboratory Solar Likeness Indicating Transducers and magnetoresistive sensors which provide body- fixed, independent angular measurements with regard to their respective local fields. Knowledge of the local field orientations and a coordinate transformation provide the inertial orientation angles, commonly called psi and theta, useful for evaluation and development of advanced flight bodies and as a navigation aid for brilliant munitions. The device is called POINTER: Projectile Orientation In Navigation TERms for a spinning body containing optical and magnetic sensors. Typical sensor data and reduction processes are reviewed and alternative field measurements are discussed.