A Matlab© based realistic simulation software is developed for Real Beam Ground Mapping (RBGM) mode of a pulsed air-borne radar. The developed software successfully simulates the effects of basic radar parameters for the real beam mapping mode. A zero level Digital Terrain Elevation Data (DiTED) is used for terrain model. Radar return is calculated for a stationary antenna at a given height from the ground and tilt angle. Simulations can represent the effects of terrain occulting, shadowing, incidence angle depended scattering, range attenuation, antenna parameters (pattern, gain, beam width e.g.) and transmitter parameters (frequency, output power, pulse width, PRF e.g.) on radar returns for both sector and circular scans.