Exploiting polarization of very low frequency scattered fields to localize objects

Most scatterers of very low frequency electromagnetic waves can be treated as equivalent dipoles. When the incident field is a plane wave, polarization of the scattered field can be exploited. In this preliminary report we assume multiple receivers lie in a plane orthogonal to the incident electric field. Receivers are positioned around the circumference of a five-meter radius circle enclosing the region of interest (ROI). Receivers are in the near field and phase of the measurements varies slowly with position, particularly for highly conductive scatterers. From noise-free (simulated) data, coordinates of a single scatterer can be recovered from nulls of the measured data. Accuracy is limited by the density of the receiver positions around the ROI. When multiple scatterers are present, some coordinates can be approximated from amplitude measurements. Additive white noise reduces accuracy of single-scatterer localization by as much as 10% when SNR=10 dB.