Magnetic detection and localization using multichannel Levinson-Durbin algorithm

摘要

The Levinson-Durbin (LD) algorithm has been used for decades as an alternative to Fast-Fourier Transforms (FFTs) in cases where several cycles of a signal are not available or too expensive to obtain. We describe a new application of this LD algorithm using spectral estimation to locate a magnetic dipole, such as a submarine or magnetic mine, relative to a high-sensitivity probe (i.e. gradiometer/ magnetometer sensor) moving through the magnetic field. The weakness of the FFT is assuming periodic inputs, thus when the sample ends at a different level than the input, the FFT incorrectly inserts a step at the 'break' between cycles; the LD algorithm benefits by assuming that nothing outside the sampling window will change the spectrum. The iterative LD algorithm is also well suited for real-time operations since it can be solved continuously while the probe moves toward the subject. By establishing spectral templates for different measurement paths relative to the source dipole, we use correlation in the spectral domain to estimate the distance of the dipole from our current path. Direction, and thus location, is obtained by simultaneously sending a second probe to complement the information gained by the first probe, together with a multidimensional LD algorithm.