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Session E3: All-source Intelligent PNT Method

Compact Navigation-Grade IMUs Based on Quartz-MEMS Technology
Sergey Zotov, Arvind Srivastava, Andrew Popp, Albert Lu, EMCORE Corporation
Date/Time: Thursday, Sep. 22, 8:35 a.m.

EMCORE is a provider of mixed-signal devices that deliver the foundation for today’s leading-edge aerospace systems and high-speed communication networks.
EMCORE delivers inertial navigation sensors and systems based on Quartz MEMS and Fiber Optic Gyro technologies. We are vertically integrated having both Quartz fabrication and LiNbO3 lithium niobate fabrication for our closed-loop FOG sensors. In 2019, Systron Donner Inertial was acquired along with their long history of producing high performing quartz MEMS inertial sensors. Together, the product portfolio includes tactical grade, high-end tactical, and navigation grade inertial measurement units as well as inertial navigation systems. Recent advancements in quartz MEMS have demonstrated navigation grade performance.
Emcore’s SDI500 MEMS IMU successfully meets the market needs in tactical grade systems. The 19 cubic inch IMU is comprised of three quartz MEMS Coriolis Vibratory Gyroscopes, CVG, and three quartz MEMS resonant accelerometers. During last two years we are lowering noise characteristics of both quartz MEMS gyroscopes and accelerometer and a new calibration method across dynamic temperature environments has been implemented for both inertial sensors. This work reports a short-tern navigation grade IMU, based on “classical” SDI500.
Experimental characterization of the MEMS gyroscopes revealed angle random walk of 0.001 °/rt-hr with bias instability of 0.01 °/hr at stable temperature. The new calibration approach allowed us to improve gyroscope bias stability over dynamic temperature (-55 °C to +85 °C) better that 0.2 °/hr (1-sigma) for the gyroscope.
Experimental characterization of the accelerometers demonstrated a velocity random walk on the order of 250 ng/rt-Hz (nano-g/rt-Hz) with bias instability of 100 ng (limited by setup mechanical noise); bias stability and scale factor across dynamic temperature (-55 °C to +85 °C) better that 0.025 mg (1-sigma) and 25 ppm respectively. Achieving the lowest reported bias/SF over dynamic temperature performance for any MEMS device, and experimentally demonstrated truly MEMS navigation grade accelerometer.



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