US 7,561,096 B2
	Subsurface imaging radar
Hans Hellsten, Linkoping (Sweden)
Assigned to SAAB AB, Linkoping (Sweden)
Filed on Feb. 08, 2008, as Appl. No. 12/28,301.
Claims priority of application No. 07446004 (EP), filed on Mar. 02, 2007.
Prior Publication US 2008/0246647 A1, Oct. 09, 2008
Int. Cl. G01S 13/90 (2006.01)

U.S. Cl. 342—22  [342/25 A; 342/188; 342/179; 342/180]

30 Claims

1. A subsurface imaging radar device comprising a transmitting unit and a receiving unit, the transmitting unit being arranged to transmit a first radio wave signal in a lobe towards a selected ground area at a selected elevation angle close to a horizontal plane in the ground area so that a significant part of the energy in a vertically polarized signal, with reference to the ground, is successively tapped by refraction into the ground area, wherein the transmitting unit is arranged to transmit the first signal as a signal being polarized, with reference to the ground, so that a significant part of the energy of the first signal is refracted into the ground area, wherein the transmitting unit is arranged to transmit the first signal with a wavelength being longer than the size of selected objects above the surface of the ground area, but short enough for detection of selected objects being subsurface, wherein the transmitting unit being arranged to transmit the first signal with a bandwidth being more than 10% of the centre frequency of the first signal for high range resolution, wherein the radar device is a wavelength resolution limited synthetic aperture radar having an azimuth resolution close to or identical to the wavelength of the first signal in order to obtain high azimuth resolution, the receiving unit being arranged to receive a second signal being the reflected first signal from the selected ground area.