Fiber-Optic / MEMS Gyroscope
Fiber-Optic Gyroscope + MEMS Backup Triad
The fiber-optic and MEMS gyroscope triad is a two-kilogram inertial sensor package that measures three-axis angular rates for lunar navigation. Operating on the Sagnac effect in optical fiber loops, the primary sensors eliminate moving parts to achieve an Allan deviation under 0.01 degrees per hour while consuming 10 watts. Maintaining autonomous navigation across a 25-year operational lifetime requires silicon MEMS backups and star tracker fixes to correct accumulated bias drift, while the 1/6 g lunar gravity gradient imparts low platform torque. Radiation-hardened ASICs process signals across a 200,000-hour mean time between failures.
Triad of fiber-optic gyroscopes (FOG) backed by MEMS gyros providing angular rate measurement for inertial navigation.
Purpose
Triad of fiber-optic gyroscopes (FOG) backed by MEMS gyros providing angular rate measurement for inertial navigation.
Context
Child of L2-NAV-IMU within the Lunar Ark system
Principles
- ▸FOG: Sagnac effect in fiber loop — no moving parts, long life
- ▸Allan deviation <0.01 deg/hr (tactical grade) achievable
- ▸Triad geometry redundant against single-axis failure
- ▸MEMS backup for fault tolerance
- ▸Rad-tolerant electronics
Typical implementations
- ▸Honeywell HG9900 FOG IMU (heritage)
- ▸Northrop Grumman LN-200 (Mars rovers)
- ▸Thales Top Star FOG (ESA)
- ▸Analog Devices MEMS IMUs (commercial)
Lunar considerations
- ▸No-moving-parts FOG ideal for long mission
- ▸Lunar gravity gradient (1/6 g) low torque on platform
- ▸Long-mission bias drift compensated via star tracker fix
Specifications
Functional
| primary function | Triad of fiber-optic gyroscopes (FOG) backed by MEMS gyros providing angular rate measurement for inertial navigation. |
| allan deg per hr | 0.01 |
| axes | 3 |
Physical
| mass kg | 2 |
| materials | FOG sensor head, Si MEMS gyros, Rad-hard ASIC |
| vacuum compatibility | True |
Operational
| power consumption w | 10 |
| thermal range c | -40, 70 |
| lifetime years | 25 |
| mtbf hours | 200000 |
Interfaces
Provides
- Angular rate triad output
Requires
- FOG laser + electronics (~10 W)
Cite this entry
Lunar Ark Codex. "Fiber-Optic / MEMS Gyroscope" (L3-NAV-IMU-GYRO). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-NAV-IMU-GYRO
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.