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Estimating the Potential Accuracy of Magnetic Navigation Based on Magnetic Survey Data

The paper discusses estimation of the potential accuracy of navigation systems using various parameters of the Earth's magnetic field with the help of the Cramer-Rao bound. For a simple measurement error model, a formula that relates the navigation accuracy and the spatial derivatives of the magnetic field is derived. A spectral method for the continuation of the magnetic field to a higher altitude is described. Using the data of geophysical surveys, the potential accuracy of navigation is estimated at various altitudes and for both field-based and gradient-based navigation systems.