LIGA Microfabricated Inertial Navigation System

DARPA wishes to exploit MEMS technology to develop a tactical grade INS. SatCon is proposing to develop an angular rate sensor combined with an accelerometer which are microfabricated on a single "chip" using the LIGA lithographic process. The accelerometer element employs a rebalanced cantilever, oriented orthogonally to the substrate, while the rate sensor uses a vibrating cylinder sensitive to rotation through Coriolis effects. The topology is simple but well-suited for moderate sensitivity, high shock performance. Acceleration can be sensed in two axes parallel to the substrate, while angular rate is detectable along the perpendicular axis. Only one structural layer is required, eliminating the complexity of overhanging features or structure-to-structure bonding. Both actuation and sensing is done electrostatically. During Phase I, half-height, but fully testable versions of the sensing structures will be fabricated by our microfabrication foundry, LSU/CAMD from a mask set already under development. The electronics to both drive and sense both the cylinder gyroscope and cantilever accelerometer will be built up and used to electronically characterize the seductress. Based upon the test results a prototype design for Phase II will be developed. Additionally, an approach to the guidance processing which accommodates the special characteristics of the performance of the sensing elements will be developed. In Phase II, prototype versions of the accelerometer structures will be fabricated from a full set of masks, operated with drive and sensing electronics under test conditions with appropriate INS software and made available to DARPA.