Calibration of the ARL BoomSAR using rigorous scattering models for fiducial targets over ground

The Army Research Laboratory (ARL) synthetic aperture radar (SAR) system is placed atop a boom lift, and therefore the system is termed a 'BoomSAR'. The UWB character of this system, covering a frequency spectrum from 40-1200 MHz, makes accurate polarimetric calibration a nontrivial matter. The response of the standard trihedral fiducial target is poorly understood at VHF and UHF frequencies, for which the wave interaction with the soil can be an important issue. Here we employ a rigorous method-of-moments (MoM) analysis of UWB scattering from a trihedral reflector over ground. The soil is modeled as a lossy, dispersive half space, accounted for rigorously via the half-space Green's function. The numerical algorithm is used to evaluate the angle-dependent, polarimetric frequency dependence of scattering from a trihedral target, at VHF and UHF frequencies. This comprehensive study of UWB scattering from a trihedral over soil is critical for system calibration.