A three dimensional (3-D) realistic radar simulation package including imaging radar simulation concept applied to multisensor scenarios is under development as a project between the Electromagnetism and Radar Department of ONERA and OKTAL-SE. Taking advantage of various studies in the domain, this partnership associates the expertise of ONERA in radar phenomenology, wave interaction with targets and clutter, with that of OKTAL-SE in the generation and management of realistic scene databases in the infrared and optical domains using advanced Shooting and Bouncing Rays (SBR) techniques [1, 2, 3]. The objective of this program is to develop simulation tools capable of predicting the behaviour of sensors in a realistic environment. This is achieved by coupling a terrain database completed by radar and optical features and a fast SBR algorithm. This paper is focused on the specification of the radar (i.e. electromagnetic wave interaction) principles. Outputs from the simulations illustrate the effectiveness of the tool in respectively, Synthetic Aperture Radar (SAR) simulations; and in the multisensor evaluation context in airborne applications such as enhanced vision in airport application context.