1. A navigation system comprising: an image acquisition device for acquiring a range image of a target vehicle at least one processor; and a memory including a target vehicle model and computer readable program code, the processor and the computer readable program code configured to cause the navigation system to: convert the range image to a point cloud having three dimensions; compute a transform from the target vehicle model to the point cloud; use the transform to estimate the target vehicle's attitude and position for capturing the target vehicle; wherein the processor and the computer readable program code are configured to generate an a priori pose estimate of the target vehicle by: comparing a target vehicle point cloud with the range image point cloud; and generating a score reflecting a fit between the target vehicle point cloud and the range image point cloud; and wherein the processor and the computer readable program code are configured to compare the target vehicle point cloud with the range image point cloud by: creating a range histogram of the range image point cloud and determining an average of coordinate values of pixels in a selected range bin of the histogram; determining a vector from an origin of the target vehicle point cloud to a center of mass of the range image point cloud; rotating the range image point cloud around the target vehicle point cloud and determining the score reflecting a fit between the target vehicle model and the point cloud; and using the rotated range image point cloud having the highest score as the a priori pose estimate of the target vehicle.