Collaborative Calibration Method for Redundant Dual-Axis RINSs Based on Geometric Constraint in GNSS-Denied Environments

Dual-axis rotational inertial navigation system (DRINS) can achieve self-calibration of error parameters through a reasonable rotation scheme. However, the traditional self-calibration methods rely on the external reference information, which fail in global navigation satellite system (GNSS)-denied environments. In long-endurance marine navigation applications, carriers are usually equipped with multiple sets of DRINS. The geometric relationship between the DRINSs can serve as constraint observation for error parameter estimation. Therefore, this article proposes a collaborative calibration method with the navigation information fusion of dual DRINSs in GNSS-denied environments. Considering scale factor error, installation error, gyro drift, accelerometer bias, and accelerometer size-effect error introduced by the rotation of dual DRINSs, a 66-D Kalman filter is established based on the geometric constraint observation. Then, a novel collaborative calibration scheme is designed through analyzing the principles of error state observability for dual DRINSs. Simulations and experiments show that all error parameters can be precisely estimated by the proposed method with the designed calibration scheme and the calibration accuracy could satisfy the demand of long-endurance marine navigation.