Over the last decade there, has been an increasing interest in developing vision systems and technologies that support the operation of unmanned platforms for positioning, mapping, and navigation. Until very recently, these developments relied on images from standard CCD cameras with a single optical center and limited field of view, making them restrictive for some applications. Panoramic images have been explored extensively in recent years. The particular configuration of interest to our investigation yields a conical view, which is most applicable for airborne and underwater platforms. Instead of a single catadioptric camera (Gluckman, J.M. and Nayar, S.K., 1999; Swaminathan, R. et al., 2001), a combination of conventional cameras may he used to generate images at much higher resolution (Negahdaripour, S. et al., Proc. Oceans, 2001). We derive complete mathematic models of projection and image motion equations for a down-looking conical camera that may be installed on a mobile platform - e.g. an airborne or submersible system for terrain flyover imaging. We describe the calibration of a system comprising multiple cameras with overlapping fields of view to generate the conical view. We demonstrate with synthetic and real data that such images provide better accuracy in 3D visual motion estimation, which is the underlying issue in 3D positioning, navigation, mapping, image registration and photo-mosaicking.