1. A subterranean imaging apparatus comprising: an antenna array comprising a plurality of radiating elements, the plurality of radiating elements configured on a land-based vehicle operable to generate electrical signals according to electromagnetic radiation reflected from a subterranean target below a ground surface; and a synthetic aperture radar (SAR) system coupled to the antenna array and operable to: transmit the electromagnetic radiation from a first subset of the plurality of radiating elements; receive the reflected electromagnetic radiation from a second subset of the plurality of radiating elements having a polarity similar to the polarity of the plurality of radiating element of the first subset, the electromagnetic radiation having a frequency that ranges from 0.1 to 2.0 Gigahertz; generate raw images from the received electrical signals; generate a weighting according to phase statistics of pixels in the raw images; and combine the raw images using the weighting to generate a refined image of the subterranean target.