System Architecture: GEM Elettronica Polaris FOG-200 Tactical FOG & AHRS
The GEM Elettronica Polaris FOG-200 is GEM Elettronica’s flagship tactical-grade gyrocompass-fog/” class=”seanav-internal-link”>Fiber Optic Gyrocompass (FOG) and Attitude and Heading Reference System (AHRS). Engineered for front-line naval combatants, frigates, corvettes, submarines, hydrographic survey ships, and dynamic positioning DP-3 vessels, the Polaris FOG-200 combines ultra-low-drift optical fiber coils with military-grade quartz accelerometers to deliver sub-tenth-degree heading precision and complete 3D spatial orientation.
Operating completely autonomously without satellite GNSS dependence, the Polaris FOG-200 provides unjammable true North heading, precise roll and pitch (< 0.05°), heave measurement, and dead-reckoning inertial holdover during GPS-denied tactical naval operations.
Technical Specifications: Polaris FOG-200 Tactical AHRS
| Parameter | Specification Details |
|---|---|
| System Classification | Tactical-Grade Naval Fiber Optic Gyrocompass & AHRS (IMO & Military Standards) |
| Core Sensors | Triaxial high-bandwidth Closed-Loop FOG + Triaxial Quartz Accelerometers |
| Settle Time | < 5 minutes dockside alignment; instant stored azimuth alignment mode |
| Static Heading Accuracy | ≤ 0.1° secant latitude (tactical survey grade) |
| Dynamic Heading Accuracy | ≤ 0.15° secant latitude under violent combat maneuvers and sea state 7 |
| Roll & Pitch Accuracy | ≤ 0.05° dynamic RMS across full 360° spatial freedom |
| Heave Measurement | 5 cm or 5% dynamic heave measurement for sonar & weapon stabilization |
| Data Interfaces | Dual IEC 61162-450 Ethernet, MIL-STD-1397 / 1553B options, 8x RS-422 NMEA 0183 (up to 100 Hz) |
| Power Input | 24 V DC (18–36 V DC) primary with 115/230 V AC dual-redundant power supplies |
| Environmental Standards | MIL-STD-810 environmental, MIL-STD-901D shock, MIL-STD-461 EMI/EMC |
Core Units, Modules & Replacement Spare Parts
| Assembly / Module | Part Reference | Technical Details |
|---|---|---|
| Tactical FOG Sensor Block | GEM-FOG200-IMU | Precision triaxial fiber optic coil pack with high-stability optical sources |
| Tactical Navigation Computer | GEM-FOG200-DSP | Multi-core real-time processor executing 36-state Kalman filtering algorithms |
| Military Display & Control Unit | GEM-FOG200-MDU | Night-vision compatible ruggedized bridge/CIC display and control terminal |
| Combat System Interface Card | GEM-FOG200-CSIC | High-speed bus interface supporting NTDS, Ethernet, and serial telemetry |
| Military Dual Power Supply | GEM-FOG200-PSU | Dual-redundant isolated power conditioning module with EMP surge arrestors |
| Heavy-Duty Shock Mount Assembly | GEM-FOG200-SHK | Mil-spec isolation dampers certified to MIL-S-901D Grade A requirements |
Seanav Tactical Field Engineering & Maintenance Support
Seanav Marine provides specialized field engineering support for naval and commercial operators utilizing the Polaris FOG-200:
- Optical Alignment & BITE Diagnostics: Analyzing internal optical loop gain, photodetector sensitivity, and accelerometer bias drifts.
- Combat System & Fire Control Integration: Calibrating high-rate attitude telemetry (up to 100 Hz) into naval combat management, sonar, and radar pedestals.
- DP System Tuning: Interfacing high-precision attitude and heading feeds into Kongsberg or Wärtsilä Dynamic Positioning controllers.
- Inertial Holdover Calibration: Testing dead-reckoning position and heading drift under simulated GPS jamming conditions.
