1. A non-transitory computer readable storage medium having a method encoded thereon, the method represented by computer readable programming code executable by a computer to perform the method comprising the steps of: constructing, given knowledge of the Earth's magnetic field vector at a DC frequency, a noise covariance model of fixed and known magnetometer sensor locations; constructing diagonalizing operators for the noise covariance model; determining whitened noise variance; determining an error variance in moment of a vessel having a given range and speed, using known track parameters; and determining an error variance for joint estimation of moment and unknown track parameters of the vessel.