[en] Three-axis magnetometers are widely used in geomagnetic field navigation. However, they are affected by magnetic distortions when installed in vehicles resulting in sensor errors. Magnetic distortions such as an eddy-current field have not been fully considered yet in compensation work. In this paper, an singular value decomposition-based Rauch–Tung–Striebel (R–T–S) fixed-interval smoothing method is proposed to compensate for the distorted field. Compensation parameters, including eddy-current coefficients, are calculated with the magnetic field data generated by a set of 3-D Helmholtz coils. The experiment is carried out to illustrate that the eddy-current field exists when the magnetic flux changes in the body coordinate system. Moreover, the proposed method has excellent performance that greatly suppresses the error to less than 5 nT, which contributes to the accuracy improvement of magnetic field measurement in the dynamic environment. (paper)