A Low-Order Gravity Disturbance Compensation Algorithm Based on Carrier Motion Constraints

Gravity disturbance compensation technology is an important means to further enhance the positioning accuracy of high-precision inertial navigation systems (INSs). In response to the challenges faced by traditional gravity disturbance acquisition methods, which are computationally complex and time-consuming, this article proposes a gravity disturbance calculation and compensation method based on carrier motion constraints. First, using velocity information as a constraint, a conversion model is constructed for the low-frequency signal of gravity disturbance to calculate the low-order spherical harmonic model. This model significantly reduces the time cost required for the gravity disturbance model computation. Second, addressing the misalignment between the actual navigation coordinate system and the ideal navigation coordinate system caused by gravity disturbances, a coordinate system correction algorithm based on the direction cosine matrix of disturbances is proposed. This algorithm enhances the positioning accuracy and reliability of high-precision INSs. Experimental results show that the proposed low-order gravity disturbance compensation algorithm based on carrier motion constraints improves the positioning accuracy by 27.89% compared to traditional algorithms while reducing computation time by 64.84%. This meets the real-time positioning requirements for long-distance navigation conditions, especially suited for UUVs, AUVs, and submarine platforms with limited computational resources, as it optimizes processing efficiency while maintaining high accuracy.