Micro-Technology for Positioning, Navigation and Timing (µPNT)

1. Micro-Technology forPositioning, Navigation and Timing(µPNT) Dr. Andrei M. Shkel

2. Aggregation • Overall goal: • Enable self-contained chip-scale inertial navigation • Reduce SWaP of existing Inertial Measurement Units (IMU) • What we have now: • CSAC, IMPACT, NGIMG, PINS (DSO) - Components • MINT, TUNS (DSO), SoOP (STO) – System Integration • Unaddressed need: • Limited dynamic range • Unacceptable long-term drift • Size, Weight, Power and Cost (no path for chip-scale IMU) • New approaches: • Exploit inertia of elastic waves for increase in dynamic range • Self-calibration on-a-chip for compensation of long-term bias drift • Integration of time and inertial measurement units for cross-calibration and SWaP&C • Why now? • Recently emerged precision manufacturing of 3D structures • Lab demonstration of bias stability improvement via mimicking inertial forces and persistent excitation • Accumulated knowledge in heterogeneous integration and algorithms

3. Durations of DOD Missions Over 70% of missile missions are less than 3 min Precision Engagement with GPS-assisted guidance Ballistic 10 sec 3 min Missile 5 Missile 9 Missile 8 Missile 7 Missile 4 M-16 Missile 2 SEALs Underwater Mission Soldier Walking in Cave Soldier Walking in Open Field New Starts Micro UAV 10,000 Missile 6 Missile 3 Missile 1 Missile 11 HMMWV Missile 10 Grenade Launcher 1,000 1 hr 100 Speed of Platform (km/hr) Personal navigation GPS-assisted 10 Currently Funded 24 hr 1 10 100 1 1,000 Range of Mission (km) Enable self-contained inertial navigation with micro systems

4. µPNT Technology Drivers • Navigation • Guidance Driving Operation Characteristics High Dynamic Range Low Power Consumption Technical Focus Area Components • NGIMG: Navigation Grade • Integrated Micro Gyroscopes • Gyros, clocks, • accels, velocity • sensors • MRIG: Micro Rate Integrating • Gyroscopes • CSAC: Chip Scale Atomic Clock • IMPACT: Integrated Micro Primary • Atomic Clock Technology System Calibration • MINT: Micro Inertial • Navigation Technology • ZUPting, persistent • excitation with • micro stages, • algorithms • PASCAL: Primary and Secondary Calibration on Active Layer • IT-MARS: Information Tethered • Micro Automated Rotary Stages Device Integration 1 1 • Fabrication • approaches, • architectures • TIMU: Deep Integration of Time and Inertial Measurement Unit • - New Starts

5. Precision Engagement Active Guidance Define Orientation Define Target Today: large & expensive sensors on static platforms Vision: small SWaP sensors extended to mobile platforms Today: GPS-assisted Vision: self-contained guidance (no GPS) in fast precision engagement Today: GPS, magnetic compass, and range finder Vision: eliminate magnetic compass with ultra-small gyro compassing solutions

6. µPNT Challenges Challenging dynamic environment, bias drift, ultra miniaturization on system-level • Deep integration of clocks & IMU • SoA clocks and sensors are incompatible, and implemented separately • Multiple non-synchronized frequency sources are used in Navigation system routinely • (power consumption, grows in uncertainty of time-position-orientation) 2 mm 2 mm • Long-term bias drift • Increased surface- to-volume ratio makes micro devices sensitive to surface effects: charging, contamination, out-gassing, trapping • This results in long-term fluctuation of physical parameters, reflected in long-term sensor drift • Fabrication processes • Dissimilar and incompatible with wafer-level parallel fabrication →SWaP & C • Can build small, but cannot build precise (~10-2relative tolerance) → performance • SoA micro-structures are fundamentally flat, non-ideal for high-g environment and fast-agile sensor concepts 2 mm • Sensors for dynamic environment • Frequency miss-match grows proportionally to input rotation rate. • Linearity of response is affected by rotation rate

7. µPNT Technical Approaches Inertia of elastic waves, self-calibration/cross-calibration algorithms, 3D fabrication • Deep integration of clocks & IMU • Develop clocks and sensors around a compatible combination of materials (Si, SiO2, Rb, Cs) • Use a single master clock for time, sync, and signal processing 2 mm 2 mm • Long-term bias drift • Compensate by applying persistent excitation via calibration stage integrated along side with sensors • Fabrication processes • Utilize under-explored process: post-release assembly, chip-level welding, stacking • Explore precision fabrication based on surface tension (~10-6projected tolerance) • 3D processes: blow, stretch, stamp, roll 2 mm • Sensors for dynamic environment • Utilize inertia of elastic waves. Precession of standing waves preserves linearity and extends the dynamic range. • Explore new materialswith large Young Modulus

8. New Approach for Solving Dynamic Range Limitations • Hemispherical Resonance Gyro (HRG) • Highly successful • “Boutique” process New approach Rate Integrating Gyroscope Rate Response Northrop Grumman HRG 3% Classical Rate Gyroscope 20 Hz 40 Hz Input Angular Rate Classical Rate Gyroscope New Approach Rate Integrating Gyroscope Axis of Rotation Elastic wave • HRG on micro scale • Exploits inertial properties of elastic waves in solids • Relies on wafer-scale fabrication of isotropic 3D solids • Results in unprecedented increase in dynamic range Price Range per axis: $50,000-$100,000

9. Self-Calibration On-a-Chip Motivation Approach • Why Now?: • Previously, technology pushed towards the “perfect” sensor • community now realizes the challenges of this approach • Phenomenon of drift not well understood • Re-calibration circumvents knowledge about the cause of drift • New emerging technological advances permit the miniaturization of rate tables for on-chip calibration Output (Voltage) Gyroscope Input (Rotation) Bias Drift (illustration) Ideal response Drifted response • Current options when sensor drifts: • Use inaccurate data • Remove sensor from system • re-calibrate in lab & • re-insert in system • discard & replace Calibration Stage 1. Co-fabricate 2. Excite 3. Extract 4. Reset reference sensor New Approach: • Fabricate sensor directly on calibration stage • Periodically apply reference stimulus (e.g. oscillatory) • Extract reference stimulus and sensor response • Recover new I/O relationship and reset bias

10. µPNT Objective • This program • HG9900 Nav grade IMU • HG1930 MEMS IMU 2 mm 2 mm The program addresses the emerging DOD need to • Decrease reliance on GPS • Increase system accuracy • Reduce co-lateral damage • Increase effective range • Reduce SWAP&C

11. µPNT Organization FY10 FY12 FY13 FY14 FY11 Components Nav-Grade Integrated Micro Gyro (NGIMG) BAA Demo 3D isotropic manufacturing Demo Rate Integrating Gyro SWaP and Performance demonstrated Micro Rate Integrating Gyroscopes (MRIG) System Calibration Micro Inertial Navigation Technology (MINT) Prim. and Sec. Calibration on Active Layer (PASCAL) Demo Sensors on Calibration Stages Demo Improvement in drift characteristics Completely Integrated System Information Tethered Micro Automated Rotary Stages (ITMARS) BAA Device Integration Chip-Scale Atomic Clock (CSAC) Timing and IMU Integration (TIMU) Demo functional T+IMU unit Demo tactical grade performance Demo Nav. grade performance Integrated Micro Primary Atomic Clock Technology (IMPACT) BAA =End of Phase =BAA