A gyrocompass is a compass with a motorized gyroscope that does not depend on magnetism and registers the direction of true north along the earth's surface.
The gyroscope consists of a spinning wheel within gimbals which allows movement on 3 mutually perpendicular axes – horizontal, vertical, and spin. When the gyro is spun rapidly, it develops gyroscopic inertia (not considering friction.) This causes it to spin in the same plane indefinitely.
The north-seeking gyrocompass that detects absolute direction from the North pole has shown excellent results in curved microtunneling projects.
Trenchlesspedia Explains Gyrocompass
A gyroscope is turned into a gyrocompass by mounting the wheel or rotor on a sphere, called a gyrosphere and supporting the sphere on a vertical ring. To make the gyrocompass seek true north, the gyro must:
- Stay on the plane of the meridian.
- Remain horizontal.
- Stay in position once it reaches north, regardless of where it is mounted.
Since the gyrocompass is not affected by magnetism, it does not vary or deviate. The error is constant and equal around the horizon and can be reduced to less than 1 degree.
The gyro navigation system is best suited for drives with internal diameter (ID) 800 to 1200 mm. The system uses self-leveling, north-seeking gyrocompass to determine the horizontal position and azimuth of the Microtunnel Boring Machine (MTBM.)