Toward Inertial-Navigation-on-Chip (eBook)

Supervisor´s Foreword 7
Acknowledgments 9
Contents 10
Parts of this thesis have been published in the following articles: 12
Chapter 1: Introduction 13
1.1 Inertial Navigation System 13
1.2 Evolution of Gyroscopes 15
1.3 Evolution of MEMS Gyroscopes 18
References 22
Chapter 2: The Physics of Resonant MEMS Gyroscopes 25
2.1 Principle of Operation 25
2.2 Non-ideal MEMS Gyroscope 30
2.2.1 Mechanical Model 30
2.2.1.1 Mode-Matching 32
2.2.1.2 Sense Output Bias 33
2.2.2 Electromechanical Transduction and Interface Circuits 34
2.2.3 Drive-Loop Transduction and Control 35
2.2.4 Sense-Mode Detection 36
2.2.5 Electrostatic Tuning 37
2.2.5.1 Stiffness Mismatch Tuning 38
2.2.5.2 Quadrature Cancellation 40
2.2.6 Electrical Noise and Errors 41
2.3 Performance Parameters 42
2.3.1 Scale-Factor and Bandwidth 42
2.3.2 Angle Random Walk 43
2.3.3 Bias Instability and Long-Term Drift 44
References 46
Chapter 3: Bias Control in Pitch and Roll Gyroscopes 47
3.1 Quadrature Cancellation 47
3.1.1 Slanted Electrode 49
3.1.2 Fabrication Implementation 50
3.2 KOH-Etched Quad-Mass Gyroscope 51
3.2.1 Design of Wet-Etched-Only Gyroscope 51
3.2.2 Simulation Results 54
3.2.3 Fabrication Process 55
3.2.4 Experimental Characterization 56
3.2.4.1 Mode-Matching Behavior 56
3.2.4.2 Gyroscope Performance Characterization 58
3.3 Dissipation and In-Phase Bias Stabilization 61
3.4 Robust Substrate-Decoupled Pitch or Roll Gyroscope 62
3.4.1 Slanted Electrode in DRIE-Based Devices 62
3.4.2 High-Frequency Annulus Gyroscope with Slanted Electrodes 64
3.4.3 Experimental Characterization 65
3.4.3.1 Resonant Behavior 66
3.4.3.2 Gyroscope Characterization 67
References 68
Chapter 4: Scale-Factor Enhancement 70
4.1 Transduction Linearity and Actuation Range 70
4.1.1 Nano-gap Comb-Drive Design 72
4.1.2 Testing Resonator Design 74
4.1.3 Experimental Characterization 75
4.2 Coriolis Sensitivity 77
4.2.1 Mode-Shape Optimization 77
4.2.2 Resonant Framed-Annulus Pitch or Roll Gyroscope 80
4.2.3 Experimental Characterization 81
4.2.3.1 Resonant Behavior 83
4.2.3.2 Gyroscope Response 83
4.2.3.3 Temperature Behavior 85
References 86
Chapter 5: Integrated Inertial Measurement Unit 87
5.1 Quasi-Solid Disk Yaw Gyroscope 87
5.2 Timing and Inertial Measurement Unit 88
5.2.1 3-Axis Gyroscopes 89
5.2.2 3-Axis Accelerometers 89
5.2.3 Timing Resonator 90
5.2.4 Experimental Characterization 91
5.2.4.1 Gyroscope Characterization 92
5.2.4.2 Accelerometer Characterization 93
5.2.4.3 Resonator Characterization 93
5.2.4.4 Summary 93
References 94
Chapter 6: Bias Stability Limit in Resonant Gyroscopes 96
6.1 Electronics and Instrument Limit 96
6.2 Demodulation Phase Error 101
6.3 Performance of Pitch or Roll Gyroscopes 109
6.3.1 Performance Scaling Comparison 109
6.3.2 Nonlinear Tuning Effect 110
Chapter 7: Conclusions and Future Work 113
7.1 Contributions 113
7.2 Future Work 114
7.2.1 Low-Power Resonant Gyroscopes 115
7.2.2 Performance Enhancement in High-Frequency Resonant Gyroscopes 116
7.2.2.1 Chip-Level Ovenization 116
7.2.2.2 System Optimization and ASIC Implementation 117
7.2.2.3 Quality-Factor Optimization 117
References 118
Appendix A: Fabrication Process 119
A.1 Wet-Etching-Based Bulk Micromachining Process 120
A.2 HARPSS+ Process 122
References 125
Appendix B: Numerical Models 126
Appendix B: Numerical Models 126
B.1 Annulus Resonator Mechanical Nonlinearity Estimation 126
B.2 MATLAB Code for Numerical Bias Instability Modeling 128
References 134