Gyro-Free Inertial Navigation Systems Based on Linear Opto-Mechanical Accelerometers.

Area of Science:

• Opto-mechanics
• Inertial Navigation Systems
• Sensor Technology

Background:

• High-sensitivity uniaxial opto-mechanical accelerometers offer precise linear acceleration measurements.
• Arrays of accelerometers can function as gyro-free inertial navigation systems, estimating linear and angular accelerations.

Purpose of the Study:

• To analyze the performance of gyro-free inertial navigation systems using opto-mechanical accelerometers.
• To evaluate systems with varying accelerometer sensitivities and bandwidths.
• To compare performance against MEMS-based inertial sensors and optical gyroscopes.

Main Methods:

• Utilized a six-accelerometer configuration for estimating linear and angular accelerations.
• Employed a linear combination of accelerometer read-outs, including a correcting term for angular velocities.
• Derived performance analytically and through simulations using experimental data for accelerometer noise.

Main Results:

• Cube configuration (0.5 m separation) showed noise levels of 10⁻⁷ m s⁻² (low-frequency) and 10⁻⁵ m s⁻² (high-frequency) at 1s Allan deviation.
• Angular velocity Allan deviation at 1s was 10⁻⁵ rad s⁻¹ (low-frequency) and 5×10⁻⁴ rad s⁻¹ (high-frequency).
• High-frequency opto-mechanical accelerometers outperformed tactical-grade MEMS for <10s (linear) and

Conclusions:

• Opto-mechanical accelerometers show promise for gyro-free inertial navigation, especially when reaching fundamental noise limits.
• Low-frequency opto-mechanical accelerometers approach fiber optical gyroscope precision for angular velocity.
• Further research is needed to address technical limitations like misalignments and initial condition errors for experimental validation.