A new IMU with a digitally controlled PZT CVG

This paper presents a new Inertial Measurement Unit aimed at near term, low cost, compact terrestrial navigation and space pointing applications. It is enabled by InertialWave's Navigation Grade CVG ASIC for precise, collocated digital control of a symmetric, piezoelectrically-transduced Coriolis Vibratory Gyro (CVG). This ASIC also provides digital readout of a co-axial accelerometer enabling a compact IMU architecture comprising three single-axis digital sensor assemblies integrated into a rigid IMU block along with a central processor for host interface. This paper reviews the need for such an IMU and current state of the art. The CVG analog electronics background and earlier breadboard concept demonstration of a lower noise digitally controlled symmetric PZT CVG achieving 0.00033 deg/rt-h ARW [1] are summarized leading to discussion of this new development of an ASIC enabled compact, low cost IMU based on this CVG and a selected accelerometer. The mechanical, electronic and digital control approaches are outlined and the planned progression of development models leading to a final IMU product are discussed including early environmental test assessment. Finally recent development test results using an enclosed CVG with front-end electronics mounted on an IMU test block with improved digital control and compensation demonstrating repeatable drift performance over an 8-hour period with 0.015 deg/h in-run stability are reported.