Detection of buried plant

A wideband microwave holographic method for imaging buried objects with high azimuth and range resolution is described. The method incorporates a synthetic aperture approach in pulse radar systems, originally designed for the pulse-echo imaging, to improve azimuth resolution. The resolving capability of the method is discussed in terms of controlling parameters such as the synthetic aperture length, soil conductivity and dielectric constant, and antenna beamwidth. Since the propagation velocity of electromagnetic wave in soil, which varies from soil to soil, is an essential parameter for reconstructing object images by the method, a method of minimum squared error estimation of the propagation velocity from a pulse-echo image is proposed. Results of underground object image reconstruction from real pulse-echo data is reported to demonstrate high estimation accuracy of the propagation velocity and fine resolution of the reconstructed image.