This paper summarizes the results we have obtained in searching for an efficient, robust, but accurate method for the estimation of the camera (or spacecraft) position based on image measurements. Based on a sequence of images acquired with a moving camera, the task is to estimate the camera position (extrinsic calibration) from corresponding points (landmarks) in the various frames. Using the noisy estimate of the camera parameters, the 3D scene points can be reconstructed. In the paper we first describe a new calibration method, and show the improvements in terms of accuracy compared to known methods. The method is studied in an application to motion estimation for a spacecraft during the orbit and landing maneuvers.