Dependance of monopulse radar boresight error on incident E-field polarization

Boresight error (BSE), the angular difference between a target's actual and radar-indicated position, is influenced by protective radomes used on airborne platforms. Research results have demonstrated a reliable computer modeling technique for predicting the BSE of electrically large radar-radome systems. This technique, based on a ray-trace receive formulation using geometric optics (GO), was extended to investigate the dependance of radome-induced BSE on various combinations of aperture scan angle, element polarization, and incident wave polarization. The results obtained compare very well with available empirical, published, and measured data for the specific scan angles and polarization cases considered. Generally, the BSE exhibits less dependance on incident wave polarization when the aperture elements are linearly polarized and a higher degree of sensitivity when aperture elements are circularly polarized.