A Novel Spatial Constraint-Based Integration Method of Multiple Single-Axis RINSs for AUV Long-Endurance Autonomous Navigation

Due to the complexity of the marine environment, the accuracy of current underwater navigation systems primarily relies on INSs. However, existing research on multi-INS fusion methods is limited, particularly in addressing the suppression of equivalent biases in the absence of positional references. This paper proposes a fusion method for multiple single-axis redundant RINS based on spatial geometric constraints. By estimating the equivalent biases in the navigation coordinate system, this method effectively suppresses navigation errors. The proposed method has been implemented and validated in the embedded acquisition system of an AUV. Experimental results indicate that the proposed method significantly enhances position and attitude accuracy compared to single RINS navigation, which can be served as an optimized navigation solution under redundant configuration conditions.