Inertial pseudo star reference unit

Summary form only given. The authors present the development of a precision pointing system, the inertial pseudo-star reference unit (IPSRU). The IPSRU implements a collimated light source mounted on an inertially stabilized platform that is configured using a centrally located two-degree-of-freedom (2-DOF) flexure assembly. The platform inertial sensing is achieved through the combined use of a precision, low-noise 2-DOF dry-tuned rotor gyro (DTG) and two angular displacement sensors (ADS). The composite gyro and ADS implementation optimally combines low-frequency gyro measurements with ADS higher frequency sensing to achieve a composite wide band, extremely low noise, and inertial sensing capability. The collimated light beam in effect becomes a jitter-stabilized pseudo-star. In addition, its pointing direction in inertial space can be changed at a precise rate by commands applied via torquing signals to the gyro