Recent Innovations in MEMS Sensors for PNT Applications

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1 Recent Innovations in MEMS Sensors for PNT Applications Stanford PNT Symposium 2017 Alissa M. Fitzgerald, Ph.D. Founder & CEO

2 Overview Navigation Developments in MEMS gyroscope technology Other MEMS sensors for navigation About AMFitzgerald Page 2

3 Navigation has always depended on sensor fusion Synthesis of information from multiple imperfect sources Page 3

4 Today, GNSS provides highly accurate navigation information Page 4

5 A proliferation of vehicles now depend on satellite navigation Page 5

6 On land, GNSS-denied environments are everywhere Page 6

7 How to operate safely in complex environments (without a $100K+ IMU)? Page 7

8 MEMS: a powerful miniaturization technology Navigation unit (1995) Navigation unit (2015) MEMS inside Approx:150 mm x 150 mm x 150mm Page 8

9 MEMS are widely used in consumer and automotive applications > 10 MEMS 1-2 MEMS > 100 MEMS! Micro Electro Mechanical Systems Page 9

10 Made by silicon (semiconductor) process technology Silicon dioxide (a.k.a. sand, dirt) Ingot Wafers Fabrication Wafer dicing Chip packaging Circuit board mount Page 10 Stanford PNT Symposium 2017 AMFitzgerald 2017

11 MEMS sensors useful for navigation Accelerometers Gyroscopes Magnetometers GE Pressure sensors Microphones IMUs (Accel+Gyro+Mag) Page 11

12 MEMS sensor qualities What s great about MEMS: Tiny size and mass Low(er) cost and power High sensitivity Compact electronics integration What s not: Tricky to package Small signals, custom ASICs often needed Stability over long duration or extreme environments Gyroscope Page 12

13 MEMS gyroscope application grade and bias stability Grade Bias stability Main Application Est. MEMS Price (in volume) Example Maturity Consumer 10 deg/sec Human motion $1 ST Micro Commercial Automotive (safety) 1 deg/sec Stability control $5 Bosch Commercial Industrial 10 deg/hr Munitions $20 ADI, Qualtre Commercial Tactical; Assisted Nav 1 deg/hr Vehicle Nav $300 SSS Commercial Short-term Nav 0.1 deg/hr Missile Nav - UMich: Najafi R&D (TRL 6) Navigation 0.01 deg/hr Aeronautics Nav - UCI: Shkel R&D (TRL 4) Strategic deg/hr Submarine Nav - DARPA C-SCAN R&D (TRL 2) Performance needed for navigation in GNSS-denied environments Page 13

14 MEMS comb-drive tuning fork gyro (consumer-automotive grade) Rotation of component exerts perpendicular Coriolis force on resonating proof mass Sealed in vacuum environment to maximize Q Capacitive comb-drives to drive/sense mass Page 14

15 MEMS comb-drive tuning fork gyro (consumer-automotive grade) 2-axis gyro (infrared photo) 2-axis gyro (SEM image) Source: ST, Chipworks iphone 4 Teardown Source: ST, Chipworks iphone 4 Teardown Page 15

16 Manufacturing tolerances limit performance of comb-drive gyros Nearly all current gyro designs inherently limited by silicon etch accuracy Non-uniform etching causes quadrature error and cross-axis coupling Lower Q = higher power consumption Work-arounds to maximize gyro performance: Cherry-picking a.k.a. binning Mode-matching designs Signal processing and compensation Top heavy etch Bottom heavy etch Edge of wafer etches faster Bigger chips can span etch zones Source: Intellisense Page 16

17 Bulk acoustic wave gyro (industrial grade) Page 17

18 Precision single-axis with inductive drive/sense (tactical grade) Source: Silicon Sensing Systems Page 18

19 Micro-scale rate integrating gyros (navigation grade) 3D MEMS structures Symmetric, atomically-smooth, high Q resonators Molded fused silica Blown ultra low expansion silicate glass Source: U Michigan, Najafi Lab Source: UC Irvine, Shkel Lab Page 19

20 Atomic gyroscopes (strategic grade) DARPA Chip-Scale Combinatorial Atomic Navigator (C-SCAN) Program Manager: R. Lutwak Two architectures being explored: Nuclear Magnetic Resonance Gyroscopes Atom-Interferometric Gyroscopes The ultimate gyroscope, which could one day enable Secretary Ash Carter s vision of making GPS obsolete MEMS-ish components useful in physics package Page 20

21 Other potentially useful MEMS for navigation and sensor fusion Infrared Imager FLIR Gas Sensors Sensirion Ultrasonic Ranging Chirp Microsystems Micro-mirrors: LIDAR Maradin Page 21

22 Conclusions Navigation continues to be the practice of sensor fusion MEMS sensors offer lightweight, low power (low CSWaP) measurements MEMS gyroscopes useful for navigation in GNSS-denied environments still in development, at least 5 years away Non-inertial sensors could augment navigation in specific applications GNSS will continue to be an essential navigation technology for at least 20 more years...while MEMS R&D grinds away on better gyros Page 22

23 About AMFitzgerald

24 AMFitzgerald creates MEMS and sensor solutions for specialty applications MEMS Innovation MEMS Solutions Technology Strategy Creation of novel devices and IP Paths to manufacturing and market Key insights from MEMS experts Page 24 Stanford PNT Symposium 2017 AMFitzgerald 2017

25 Development services from concept to production AMFitzgerald in-house Strategic partners Custom MEMS development for commercial production Rapid prototyping on state-of-the-art tools Supply chain creation and management Focus on high-performance, specialty silicon devices Headquarters in Burlingame, CA Fab operations at 1500m 2 UCB Marvell Nanolab Page 25 Stanford PNT Symposium 2017 AMFitzgerald 2017

26 Our work is at the leading edge in many markets AMFitzgerald typical annual revenue, by market Aircraft, spacecraft sensors Cardiology guidewires, pacemakers, pumps; diagnostic chips Microphones, pollution detectors Atomic sensors, commercial print heads, quantum computers Fiber optic networking, laser system components, infrared detectors Page 26 Stanford PNT Symposium 2017 AMFitzgerald 2017

27 Company contact information 700 Airport Blvd. Suite 210 Burlingame, CA 94010, USA Phone: +1 (650) 347 MEMS Fax: +1 (650) General Inquiries: Page 27 Stanford PNT Symposium 2017 AMFitzgerald 2017

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