This study discusses the condition of Wide-Field-Integration (WFI) of optic flow to make it as a realistic guidance and navigation system for space probes. WFI of optic flow is a bio-inspired navigation system mimicking visual processing system of flying insects using their compound eyes. However, in a real system, photoreceptors on a spherical surface used in WFI of optic flow are replaced by pixels on flat image surfaces of cameras, and the camera's field of view is limited. This paper examines the effect of the realistic restrictions for WFI of optic flows on the estimation performance in numerical simulations. The estimation accuracy is evaluated for several parameters: the field of view and the resolution of a camera, which is used instead of photoreceptors. Effects of space probe motion and sensor noises are also evaluated. It is shown that a camera with a wider field of view shows better accuracy, when the total number of pixels (or photoreceptors) is same.