In inertial navigation, a compass refers to a device used to determine direction relative to the Earth’s magnetic field. It is often integrated with an Inertial Navigation System (INS) to provide heading information, which helps correct drift errors in long-duration navigation.
Types of Compasses in Inertial Navigation
Magnetic Compass – Measures Earth’s magnetic field to determine magnetic north, commonly used in basic navigation systems.
Digital Magnetic Compass (DMC) – Uses magnetometers and accelerometers to calculate heading with compensation for tilt and interference.
Gyrocompass – Uses a fiber optic gyroscope (FOG) or a ring laser gyroscope (RLG) to determine true north by detecting Earth’s rotation. Unlike a magnetic compass, it is unaffected by local magnetic disturbances.
North-Finding INS – Advanced fiber optic or MEMS-based inertial systems that autonomously determine true north without reliance on external magnetic fields.
How a Compass Supports INS Navigation
• Corrects Heading Drift – An INS alone suffers from drift over time; a compass can provide periodic corrections.
• Operates in GPS-Denied Environments – In submarines, underground tunnels, or electronic warfare zones, a gyrocompass or north-finding INS helps maintain accurate heading.
• Enhances Sensor Fusion – Combined with GNSS, accelerometers, and gyroscopes, a compass improves overall navigation accuracy.
