1. A method of determining a direction of a target in a ground referential, the method comprising: acquiring an image of a scene including the target and a control object using a camera; obtaining position data of the camera and control object using a geo-spatial positioning system; determining a control direction from the camera to the control object in the ground referential using said position data; estimating a camera attitude in the ground referential using the control direction; determining the target direction from the camera to the target using the estimated camera attitude and a pixel position of the target in the image.