An eight-position self-calibration method for a dual-axis rotational Inertial Navigation System

• Eight-position self-calibration for a dual-axis rotational Inertial Navigation System.
• Calibrating g-dependent bias by two more positions with tilt attitudes.
• Improving navigation accuracy by more than 50%.
• Feasible for both static and in-motion environment.

An eight-position self-calibration method for a dual-axis rotational Inertial Navigation System (INS) is provided in this paper. By experiencing two more positions with tilt attitudes than those experienced in a conventional six-position method, not only constant biases, scale factor errors, and misalignment errors, but also g-dependent biases can be calibrated. Field tests indicate that, after the calibration and compensation of the g-dependent biases, both a latitude error and a longitude error remain within a small range over time. In contrast, by using the conventional six-position method, a latitude error is several times larger and a longitude error diverges rapidly over time. Compared with the six-position method, accuracy of the dual-axis rotational INS is significantly improved more than 50% by the eight-position self-calibration method. The self-calibration method is feasible both in static and over a ship at the dockside.