The north seeking gyro element of the NAVIGAT 3000 gyro compass system is the fibre optic sensor unit. It is a solid-state design with no moving parts. Designed in strap-down technology, it is attached directly to the vessel, eliminating the use of a gimbal system. The sensor unit contains three fibre optic rate sensors, an accelerometer triade, a navigation- and I/O-processor unit and a power supply.

The three rate gyros are arranged orthogonally and measure thus the rotation of the sensor unit about a vessel’s x, y and z axes. The MEMS-accelerometer triade measures the linear acceleration of the x, y and z axes of the vessel.

Kalman Filter

The above gyro configuration is known as an “analytical platform”. On the basis of the vessel-referenced sensor data and the external speed and position (LAT. & LON.) inputs, the navigation processor uses a complex Kalman Filter algorithm to when seeking true north.

To initialize the Kalman Filter parameters, an alignment procedure is carried out when the system is energized or when an alignment command is received. During the alignment procedure and during normal operation, the Kalman Filter continually and simultaneously performs two essential tasks which make it north seeking, namely horizontal alignment and north orientation. After power-up, the system establishes a virtual plane, the so-called inertial plane.

For more information about Northrop Grumman Sperry Marine’s NAVIGAT 3000 Gyro Compass, please contact us.